Survival rates and safety associated with chemoradiotherapy followed by surgery and chemoradiotherapy alone for patients with T4 esophageal cancer: a systematic review and meta-analysis.

BACKGROUND: The optimal treatment approach for T4 esophageal cancer is not well established. We aimed to perform a systematic review and meta-analysis to determine the survival rates and safety of chemoradiotherapy followed by surgery (CRT-S) and chemoradiotherapy alone (CRT) in patients with T4 Nany M0 esophageal cancer. MATERIALS AND METHODS: We searched databases for eligible prospective or retrospective studies. The outcomes of interest were overall survival (OS) at 1, 3 and 5 years, treatment-related fistula formation and mortality rates. Meta-analyses were performed using the random effects models separately for studies evaluating CRT-S and CRT. Subgroup analyses were performed based on histology, radiation dose, chemotherapy regimen and duration of the interval between CRT and surgery. RESULTS: We identified 23 studies including 1,119 patients with predominantly squamous cell carcinoma (93%) and adenocarcinoma (3%) histology. The OS rates of patients receiving CRT-S were 65%, 36% and 20% at 1, 3 and 5 years, respectively. The OS rates of patients receiving CRT were 30%, 11% and 10% at 1, 3 and 5 years, respectively. Treatment-related fistula formation rates were 4% for CRT-S and 9% for CRT. Treatment-related mortality rates were 3% for both groups. Subgroup analyses showed that the interval of >2 months between CRT and surgery was associated with significantly improved OS rates at 1, 3 and 5 years. CONCLUSION: Chemoradiotherapy is an efficacious treatment approach for T4 esophageal cancer, with clinically acceptable rates of treatment-related fistula formation and mortality. Tri-modality approach with surgery can be considered in carefully selected patients. Our study findings should be interpreted with caution due to the lack of high-quality evidence. Randomized controlled trials are warranted to confirm these findings.

Palliative radiotherapy for bladder cancer: a systematic review and meta-analysis.

BACKGROUND/PURPOSE: The optimal dose fractionation for palliative radiotherapy (RT) in patients with symptomatic advanced bladder cancer is unclear. This study aimed to determine if a higher dose of RT was associated with improved symptoms response rates. METHODS: We searched PubMed, Central and Embase for eligible studies published from 1990 to 2019. The primary outcomes were symptoms response rates for hematuria, dysuria and frequency. Secondary outcomes included treatment-related adverse events and quality of life. RESULTS: We found one randomized, four prospective and eight retrospective non-comparative observational studies including 1320 patients who received palliative bladder radiotherapy for symptom relief. The dose fractionation schedules varied across studies ranging from 8 Gy single fraction to 60 Gy in 2 to 8 Gy per fraction. The pooled response rates for hematuria, dyuria and frequency symptoms were 74%, 58% and 71% respectively. A higher dose of RT was not associated with improved response rates of hematuria and frequency. However, a higher dose of RT was associated with a longer duration of hematuria response and reduced response of dysuria. Grade 3 gastrointestinal and genitourinary toxicity occurred in up to 26% of patients. Health-related quality of life (HRQOL) outcomes were reported in one study. CONCLUSION: This systematic review demonstrates that a higher dose of bladder RT was not associated with improved response rates of hematuria and frequency symptoms but was associated with reduced response of dysuria. Higher doses of bladder RT was associated with more durable hematuria response. Prospective studies to determine the effects of palliative bladder radiotherapy on HRQOL outcomes are warranted.

Utility of magnetic resonance imaging in determining treatment response and local recurrence in nasopharyngeal carcinoma treated curatively.

BACKGROUND: To determine the optimal timing of the first Magnetic Resonance Imaging (MRI) scan after curative-intent radiotherapy (RT) for nasopharyngeal carcinoma (NPC), and evaluate the role of MRI in surveillance for locoregional recurrence (LRR). METHODS: Patients with non-metastatic NPC treated radically who had at least one post-treatment MRI (ptMRI) done were included for analysis. ptMRI reports were retrospectively reviewed and categorised as complete response (CR), partial response/residual disease (PR) or indeterminate (ID). Patients with LRR were assessed to determine if initial detection was by MRI or clinical means. Univariable and multivariable Cox proportional hazard regression analysis were performed to identify independent factors associated with CR on ptMRIs. RESULTS: Between 2013 and 2017, 262 eligible patients were analysed, all treated with Intensity Modulated Radiotherapy (IMRT). Median time from end of RT to the first ptMRI was 93 days (range 32-346). Of the first ptMRIs, 88 (33.2%) were CR, 133 (50.2%) ID, and 44 (16.6%) PR. A second ptMRI was done for 104 (78.2%) of 133 patients with ID status. In this group, 77 (57.9%) of the subsequent MRI were determined to be CR, 21(15.8%) remained ID and 6 (4.5%) PR. T1 tumour stage and AJCC stage I were associated with increased CR rates on first ptMRI on multivariable analysis. ID status was more likely at 75-105 days (3 months +/- 15 days) vs 106-135 days (4 months +/- 15 days) post RT (OR 2.13, 95% CI 1.16-4.12, p = 0.024). LRR developed in 27 (10.1%) patients; 20 (74.1%) were initially detected through MRI, 3 (11.1%) by nasoendoscopy and 2 (7.4%) by PET-CT. CONCLUSION: MRI is useful for detecting local recurrence or persistent disease after curative-intent treatment. Most patients will need more than one ptMRI to arrive at a definitive status. The rate of ID ptMRI may be reduced by delaying the first scan to around 4 months post RT.

Impact of programmed death-ligand 1 expression on the patients of stage IV non-small cell lung cancer harboring epidermal growth factor receptor mutation: a systematic review and meta-analysis.

BACKGROUND: To determine the impact of programed death-ligand 1 (PD-L1) expression on progression-free survival (PFS) outcomes in stage IV epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) treated with first-line EGFR tyrosine kinase inhibitors (TKIs). MATERIAL AND METHODS: We searched biomedical databases for studies comparing PFS outcomes of PD-L1-positive versus (vs) PD-L1-negative tumors. We assessed the methodological quality of eligible studies using ROBINS-I tool. We employed a two-staged meta-analysis approach by reconstructing individual patient data of each study from the published Kaplan-Meier curves and then pooling the individual hazard ratios (HRs) and weighted mean differences (WMDs) for restricted mean PFS time at 6 (RMPFST6) and 12 (RMPFST12) months using random-effect models. We assessed the quality of summarized evidence using GRADE approach. RESULTS: We identified five non-randomized comparative studies including 435 patients. The overall risk of bias in the methodological quality of included studies was moderate. PD-L1-positive tumors were associated with significantly worse PFS outcomes compared to PD-L1-negative tumors (HR: 2.41, 95% confidence interval (CI): 1.59-3.66, p < .001; WMD in RMPFST6: -1.01, 95% CI: -1.65 to -0.37, p = .002; WMD in RMPFST12: -2.64, 95% CI: -4.40 to -0.88, p = .003). Subgroup analysis showed that the effect of PD-L1 expression on PFS outcomes was greater for studies using older-generation rather than third-generation TKIs (HR: 2.69 vs 1.22, p = .069; WMD in RMPFST6: -1.23 vs -0.07, p = .005; WMD in RMPFST12: -3.29 vs -0.12, p = .003). The quality of summarized evidence was judged to be low. CONCLUSION: There is low certainty in the evidence to suggest that positive PD-L1 expression is associated with inferior disease control and survival outcomes in patients with stage IV EGFR-mutated NSCLC treated with first-line EGFR TKIs.

Frequency of discordance in programmed death-ligand 1 (PD-L1) expression between primary tumors and paired distant metastases in advanced cancers: a systematic review and meta-analysis.

Background: To determine the frequency of discordance in programmed death-ligand 1(PD-L1) expression between primary tumors and paired distant metastases in advanced cancers.Methods: We searched MEDLINE and EMBASE for eligible studies and assessed their methodologic quality using QUADAS-2 tool. We estimated the discordant rates (positive to negative or vice versa) of PD-L1 expression in primary tumors and paired distant metastases using logistic-normal random effects model. We performed subgroup analyses based on the PD-L1 status of primary tumors (positive or negative), location of primary tumors (lung or others) and distant metastases (central nervous system or others), timing of distant metastases (synchronous or metachronous), positivity thresholds of PD-L1 expression (1% or 5%) and types of antibody clones used (E1L3N or SP142).Results: Thirteen eligible studies including 451 cases were identified. The included studies were judged to have low to unclear risk of bias. The pooled estimate of discordant rates in PD-L1 expression was 31% (95% CI= 19-47%), with high heterogeneity across the studies (I2 = 75%). There was no significant effect modification in the discordant rates according to the predefined subgroups.Conclusion: Approximately one-third of advanced cancer cases have discordance in PD-L1 expression between primary tumors and paired distant metastases. A more liberal testing of PD-L1 expression in both primary and metastatic tumors is recommended in order to identify patients who may benefit from immune checkpoint blockade treatment. Further research exploring the mechanisms and its impact are warranted.

Chemoradiotherapy versus chemoradiotherapy plus surgery for esophageal cancer.

BACKGROUND: Please see Appendix 4 for a glossary of terms.The outcome of patients with esophageal cancer is generally poor. Although multimodal therapy is standard, there is conflicting evidence regarding the addition of esophagectomy to chemoradiotherapy. OBJECTIVES: To compare the effectiveness and safety of chemoradiotherapy plus surgery with that of chemoradiotherapy alone in people with nonmetastatic esophageal carcinoma. SEARCH METHODS: We performed a computerized search for relevant studies, up to Feburary 2017, on the CENTRAL, MEDLINE, and Embase databases using MeSH headings and keywords. We searched five online databases of clinical trials, handsearched conference proceedings, and screened reference lists of retrieved papers. SELECTION CRITERIA: We included randomized controlled trials (RCTs) comparing chemoradiotherapy plus esophagectomy with chemoradiotherapy alone for localized esophageal carcinoma. We excluded RCTs comparing chemotherapy or radiotherapy alone with esophagectomy. DATA COLLECTION AND ANALYSIS: Two authors independently selected studies, extracted data, and assessed risk of bias and the quality of the evidence, using standardized Cochrane methodological procedures. The primary outcome was overall survival (OS), estimated with Hazard Ratio (HR). Secondary outcomes, estimated with risk ratio (RR), were local and distant progression-free survival (PFS), quality of life (QoL), treatment-related mortality and morbidity, and use of salvage procedures for dysphagia. Data were analyzed using a random effects model in Review Manager 5.3 software. MAIN RESULTS: From 2667 references, we identified two randomized studies, in six reports, that included 431 participants. All participants were clinically staged to have at least T3 and/or node positive thoracic esophageal carcinoma, 93% of which was squamous cell histology. The risk of methodological bias of the included studies was low to moderate.High-quality evidence found the addition of esophagectomy had little or no difference on overall survival (HR 0.99, 95% CI 0.79 to 1.24; P = 0.92; I² = 0%; two trials). Neither study reported PFS, therefore, freedom from loco-regional relapse was used as a proxy. Moderate-quality evidence suggested that the addition of esophagectomy probably improved freedom from locoregional relapse (HR 0.55, 95% CI 0.39 to 0.76; P = 0.0004; I² = 0%; two trials), but low-quality evidence suggested it may increase the risk of treatment-related mortality (RR 5.11, 95% CI 1.74 to 15.02; P = 0.003; I² = 2%; two trials).The other pre-specified outcomes (quality of life, treatment-related toxicity, and use of salvage procedures for dysphagia) were reported by only one study, which found very low-quality evidence that use of esophagectomy was associated with reduced short-term QoL (MD 0.93, 95% CI 0.24 to 1.62), and low-quality evidence that it reduced use of salvage procedures for dysphagia (HR 0.52, 95% CI 0.36 to 0.75). Neither study compared treatment-related morbidity between treatment groups. AUTHORS' CONCLUSIONS: Based on the available evidence, the addition of esophagectomy to chemoradiotherapy in locally advanced esophageal squamous cell carcinoma, provides little or no difference on overall survival, and may be associated with higher treatment-related mortality. The addition of esophagectomy probably delays locoregional relapse, however, this end point was not well defined in the included studies. It is undetermined whether these results can be applied to the treatment of adenocarcinomas, tumors involving the distal esophagus and gastro-esophageal junction, and to people with poor response to chemoradiation.

Does Prior Respiratory Viral Infection Provide Cross-Protection Against Subsequent Respiratory Viral Infections? A Systematic Review and Meta-Analysis.

The epidemiology of different respiratory viral infections is believed to be affected by prior viral infections in addition to seasonal effects. This PROSPERO-registered systematic review identified 7388 studies, of which six met our criteria to answer the question specifically. The purpose of this review was to compare the prevalence of sequential viral infections in those with previously documented positive versus negative swabs. The pooled prevalence of sequential viral infections over varying periods from 30-1000 days of follow-up was higher following a negative respiratory viral swab at 0.15 than following a positive swab at 0.08, indicating the potential protective effects of prior respiratory viral infections. However, significant heterogeneity and publication biases were noted. There is some evidence, albeit of low quality, of a possible protective effect of an initial viral infection against subsequent infections by a different virus, which is possibly due to broad, nonspecific innate immunity. Future prospective studies are needed to validate our findings.

Stroke Risk in Survivors of Head and Neck Cancer.

Importance: Survivors of head and neck cancers (HNC) have increased risk of stroke. A comprehensive report using standardized methods is warranted to characterize the risk and to inform on survivorship strategy. Objective: To determine the stroke risk in subpopulations of survivors of HNC in Singapore. Design, Setting, and Participants: This national, registry-based, cross-sectional study aimed to estimate stroke risk in subgroups of the HNC population between January 2005 and December 2020. Participants were identified from the Singapore Cancer Registry, the Singapore Stroke Registry, and the Registry of Birth and Deaths using relevant International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) codes. HNC subgroups were defined based on patient demographic, disease, and treatment factors. Data were analyzed from September 2022 to September 2023. Exposure: Diagnosis of HNC. Main Outcomes and Measures: Both ischemic and hemorrhagic stroke were studied. The age-standardized incidence rate ratio (SIRR) and age-standardized incidence rate difference (SIRD) were reported. The Singapore general population (approximately 4 million) served as the reference group for these estimations. Results: A total of 9803 survivors of HNC (median [IQR] age at diagnosis, 58 [49-68] years; 7166 [73.1%] male) were identified. The most common HNC subsites were nasopharynx (4680 individuals [47.7%]), larynx (1228 individuals [12.5%]), and tongue (1059 individuals [10.8%]). A total of 337 individuals (3.4%) developed stroke over a median (IQR) follow-up of 42.5 (15.0-94.5) months. The overall SIRR was 2.46 (95% CI, 2.21-2.74), and the overall SIRD was 4.11 (95% CI, 3.37-4.85) strokes per 1000 person-years (PY). The cumulative incidence of stroke was 3% at 5 years and 7% at 10 years after HNC diagnosis. The SIRR was highest among individuals diagnosed at younger than 40 years (SIRR, 30.55 [95% CI, 16.24-52.35]). All population subsets defined by age, sex, race and ethnicity, HNC subsites (except tongue), stage, histology, and treatment modalities had increased risk of stroke compared with the general population. The SIRR and SIRD were significantly higher among individuals who had a primary radiation treatment approach (SIRR, 3.01 [95% CI, 2.64-3.43]; SIRD, 5.12 [95% CI, 4.18-6.29] strokes per 1000 PY) compared with a primary surgery approach (SIRR, 1.64 [95% CI, 1.31-2.05]; SIRD, 1.84 [95% CI, 0.923.67] strokes per 1000 PY). Conclusions and Relevance: In this cross-sectional study of survivors of HNC, elevated stroke risks were observed across different age, subsites, and treatment modalities, underscoring the importance of early screening and intervention.

Management of advanced prostate cancer in the Asia-Pacific region: Summary of the Asia-Pacific Advanced Prostate Cancer Consensus Conference 2023.

AIM: The aim of the third Asia-Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2023) was to discuss the application in the Asia-Pacific (APAC) region of consensus statements from the 4th Advanced Prostate Cancer Consensus Conference (APCCC 2022). METHODS: The one-day meeting in July 2023 brought together 27 experts from 14 APAC countries. The meeting covered five topics: (1) Intermediate- and high-risk and locally advanced prostate cancer; (2) Management of newly diagnosed metastatic hormone-sensitive prostate cancer; (3) Management of non-metastatic castration-resistant prostate cancer; (4) Homologous recombination repair mutation testing; (5) Management of metastatic castration-resistant prostate cancer. Pre- and post-symposium polling gathered APAC-specific responses to APCCC consensus questions and insights on current practices and challenges in the APAC region. RESULTS: APAC APCCC highlights APAC-specific considerations in an evolving landscape of diagnostic technologies and treatment innovations for advanced prostate cancer. While new technologies are available in the region, cost and reimbursement continue to influence practice significantly. Individual patient considerations, including the impact of chemophobia on Asian patients, also influence decision-making. CONCLUSION: The use of next-generation imaging, genetic testing, and new treatment combinations is increasing the complexity and duration of prostate cancer management. Familiarity with new diagnostic and treatment options is growing in the APAC region. Insights highlight the continued importance of a multidisciplinary approach that includes nuclear medicine, genetic counseling, and quality-of-life expertise. The APAC APCCC meeting provides an important opportunity to share practice and identify APAC-specific issues and considerations in areas of low evidence where clinical experience is growing.

Outcome of 6 fractions of 5.3 Gray HDR brachytherapy in combination with external beam radiotherapy for treatment of cervical cancer.

OBJECTIVE: To review the characteristics, outcomes and toxicities of cervical cancer patients treated with 6 fractions of brachytherapy after external beam radiotherapy (EBRT). METHODS: All patients diagnosed with cervical cancer from 2000 to 2009 who were referred for radical treatment and who received 6 fractions of brachytherapy were retrospectively reviewed. Overall survival (OS), disease free survival (DFS), local control (LC), distant control (DC) rate, acute and late toxicities were the primary endpoints. RESULTS: Thirty-two patients with mainly advanced stage squamous cell carcinoma were identified and reviewed. Patients received EBRT of 45 to 50.4 Gy in 1.8 Gy daily fractions followed by 6 sessions of 3 channel brachytherapy of 5.3 Gy prescribed to point H. Response rates to treatment were good, with no residual disease in 84% six weeks after the completion of treatment. With a median follow up time of 8.1 years, the five-year OS, DFS, LC and distant control rates were 75%, 68.5%, 92.8% and 76.9% respectively. None of the patients developed any G3-4 acute toxicity but one patient who had advanced disease developed G3-4 proctitis with a fistula formation. CONCLUSIONS: HDR brachytherapy utilizing 6 fractions of 5.3 Gy prescribed to point H with concurrent chemo-radiation is superior in terms of OS and LC to regimens that deliver a lower EQD2 dose to point A/H and is associated with very low rates of toxicities.

Outcomes of Patients With Spinal Metastases From Prostate Cancer Treated With Conventionally-Fractionated External Beam Radiation Therapy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate the outcomes of conventionally-fractionated external beam radiation therapy (cEBRT) in the treatment of prostate cancer spinal metastases (PCSM). METHODS: Patients who received palliative cEBRT for PCSM in our institution between 2008 and 2018 were included. Our outcomes were local progression-free survival (LPFS), overall survival (OS), pain response and toxicities graded using CTCAE version 4.03. Univariable and multivariable Cox proportional hazard regressions were performed to identify predictors for LPFS and OS. RESULTS: A total of 100 patients with 132 sites of PCSM were identified, with a median follow-up of 54 months. Fourteen-percent of patients underwent surgical intervention before receiving cEBRT. Eighteen spinal segments (13.6%) had local progression, with a median time to local progression of 8 months. The median LPFS and OS were 7.8 and 9.0 months, respectively. The complete and partial pain response rates were 57% and 39% respectively. The incidence of grade ≥3 acute toxicities was 11%. Better ECOG performance status (0 to 1), castration-sensitive disease, spinal surgery and use of novel antiandrogen agent were identified as significant predictors for improved OS on multivariable analysis. CONCLUSIONS: In our prostate cancer cohort, cEBRT is an effective treatment modality for local palliation of spinal metastases. More aggressive treatment approach should be considered for patients with excellent performance status and castration-sensitive disease in light of their expected longer survival. Further studies are warranted to identify the predictors for radiotherapy response in this population.

Effectiveness of Immune Checkpoint Inhibitors in Patients With Advanced Esophageal Squamous Cell Carcinoma: A Meta-analysis Including Low PD-L1 Subgroups.

Importance: Immune checkpoint inhibitors (ICIs) have improved survival outcomes of patients with advanced esophageal squamous cell carcinoma in both first- and second-line settings. However, the benefit of ICIs in patients with low programmed death ligand 1 (PD-L1) expression remains unclear. Objective: To derive survival data for patient subgroups with low PD-L1 expression from clinical trials comparing ICIs with chemotherapy in esophageal squamous cell carcinoma and to perform a pooled analysis. Data Sources: Kaplan-Meier curves from the randomized clinical trials were extracted after a systematic search of Scopus, Embase, PubMed, and Web of Science from inception until October 1, 2021. Study Selection: Randomized clinical trials that investigated the effectiveness of anti-PD-1-based regimens for advanced esophageal squamous cell carcinoma and that reported overall survival (OS), progression-free survival, or duration of response were included in this meta-analysis. Data Extraction and Synthesis: Kaplan-Meier curves of all-comer populations, subgroups with high PD-L1, and those with low PD-L1 (when available) were extracted from published articles. A graphic reconstructive algorithm was used to calculate time-to-event outcomes from these curves. In studies with unreported curves for subgroups with low PD-L1 expression, KMSubtraction was used to impute survival data. KMSubtraction is a workflow to derive unreported subgroup survival data with from subgroups. An individual patient data pooled analysis including previously reported and newly imputed subgroups was conducted for trials with the same treatment line and PD-L1 scoring system. Data analysis was conducted from January 1, 2022, to June 30, 2022. Main Outcomes and Measures: Primary outcomes included Kaplan-Meier curves and hazard ratios (HRs) for OS for subgroups with low PD-L1 expression. Secondary outcomes included progression-free survival and duration of response. Results: The randomized clinical trials CheckMate-648, ESCORT-1st, KEYNOTE-590, ORIENT-15, KEYNOTE-181, ESCORT, RATIONALE-302, ATTRACTION-3, and ORIENT-2 were included, totaling 4752 patients. In the pooled analysis of first-line trials that evaluated a tumor proportion score (CheckMate-648 and ESCORT-1st), no significant benefit in OS was observed with immunochemotherapy compared with chemotherapy in the subgroup of patients who had a tumor proportion score lower than 1% (HR, 0.91; 95% CI, 0.74-1.12; P = .38) compared with chemotherapy. In the pooled analysis of first-line trials that evaluated combined positive score (KEYNOTE-590 and ORIENT-15), there was a significant but modest OS benefit for immunochemotherapy compared with chemotherapy in the subgroup with a combined positive score lower than 10 (HR, 0.77; 95% CI, 0.62-0.94; P = .01). Conclusions and Relevance: Findings suggest a lack of survival benefit of ICI-based regimens in the first-line setting compared with chemotherapy alone in the subgroup with a tumor proportion score lower than 1%.

Radiation Oncology Research in Asia: Current Status and a Peep Into the Future From the Federation of Asian Organizations for Radiation Oncology.

PURPOSE: This survey was conducted to assess the current research practices among the 14 members of the Federation of Asian Organizations for Radiation Oncology (FARO) committee, to inform measures for research capacity building in these nations. MATERIALS AND METHODS: A 19-item electronic survey was sent to two research committee members from the 14 representative national radiation oncology organizations (N = 28) that are a part of FARO. RESULTS: Thirteen of the 14 member organizations (93%) and 20 of 28 members (71.5%) responded to the questionnaire. Only 50% of the members stated that an active research environment existed in their country. Retrospective audits (80%) and observational studies (75%) were the most common type of research conducted in these centers. Lack of time (80%), lack of funding (75%), and limited training in research methodology (40%) were cited as the most common hindrances in conducting research. To promote research initiatives in the collaborative setting, 95% of the members agreed to the creation of site-specific groups, with head and neck (45%) and gynecological cancers (25%) being the most preferred disease sites. Projects focused on advanced external beam radiotherapy implementation (40%), and cost-effectiveness studies (35%) were cited as some of the potential areas for future collaboration. On the basis of the survey results, after result discussion and the FARO officers meeting, an action plan for the research committee has been created. CONCLUSION: The results from the survey and the initial policy structure may allow facilitation of radiation oncology research in the collaborative setting. Centralization of research activities, funding support, and research-directed training are underway to help foster a successful research environment in the FARO region.

Indirect Treatment Comparison of First-Line CDK4/6-Inhibitors in Post-Menopausal Patients with HR+/HER2- Metastatic Breast Cancer.

Background: CDK4/6-inhibitors have demonstrated similar efficacy and are considered an effective first-line endocrine treatment of patients with hormone-receptor positive (HR+)/human-epidermal-growth-factor-receptor-2 negative (HER2-) metastatic breast cancer (MBC) in the endpoint of progression-free survival (PFS). Amongst these, palbociclib was first to achieve regulatory approval, followed subsequently by ribociclib and abemaciclib. However, recent updates of overall survival (OS) showed inconsistencies in the OS benefit for palbociclib compared with the other two CDK4/6-inhibitors. With the lack of head-to-head comparison studies, our study sought to compare indirect survival outcomes between CDK4/6-inhibitors in this setting using a novel reconstructive algorithm. Methods: Phase III randomized trials comparing first-line aromatase inhibitor with/without a CDK4/6-inhibitor in post-menopausal patients with HR+/HER2- MBC were identified through systemic review and literature search of online archives of published manuscripts and conference proceedings. A graphical reconstructive algorithm was utilized to retrieve time-to-event data from reported Kaplan-Meier OS and PFS plots to allow for comparison of survival outcomes. Survival analyses were conducted with Cox proportional-hazards model with a shared-frailty term. Results: Three randomized phase III trials-PALOMA-2, MONALEESA-2 and MONARCH-3-comprising 1827 patients were included. Indirect pairwise comparisons of all CDK4/6-inhibitors showed no significant PFS differences (all p > 0.05). Likewise, indirect treatment comparison between ribociclib vs. palbociclib (one-stage: HR = 0.903, 95%-CI: 0.746-1.094, p = 0.297), abemaciclib vs. palbociclib (one-stage: HR = 0.843, 95%-CI: 0.690-1.030, p = 0.094) and abemaciclib vs. ribociclib (one-stage: HR = 0.933, 95%-CI: 0.753-1.157, p = 0.528) failed to demonstrate a significant OS difference. Conclusions: Findings from this indirect treatment comparison suggest no significant PFS or OS differences between CDK4/6-inhibitors in post-menopausal patients with HR+/HER2- MBC.

Restaging of rectal cancer with hybrid positron emission tomography magnetic resonance imaging after preoperative chemoradiotherapy.

Introduction: This study determines the sensitivity and specificity of positron emission tomography/magnetic resonance imaging (PET/MRI) parameters in predicting treatment response in patients with localised rectal cancer who have undergone preoperative chemoradiotherapy (CRT). Method: Patients with stage I-III adenocarcinoma of the rectum planned for preoperative CRT followed by surgery were recruited. Patients had PET/MRI scans at baseline and 6-8 weeks post-CRT. Functional MRI and PET parameters were assessed for their diagnostic accuracy for tumour regression grade (TRG). Nonparametric receiver operating characteristic analysis was employed to determine the area under the ROC curve (AUC), and the sensitivity and specificity of each quantile cut-off. Results: A total of 31 patients were recruited, of whom 20 completed study protocol. All patients included had mid or lower rectal tumours. There were 16 patients (80%) with node-positive disease at presentation. The median time to surgery was 75.5 days (range 52-106 days). Histopathological assessment revealed 20% good responders (TRG 1/2), and the remaining 80% of patients had a poor response (TRG 3/4). When predicting good responders, the AUC values for percent maximum thickness reduction and percent apparent diffusion coefficient (ADC) change were 0.82 and 0.73, respectively. A maximum thickness reduction cut-off of >47% and a percent ADC change of >20% yielded a sensitivity and specificity of 75%/95% and 75%/73%, respectively. Conclusion: Parameters such as percent maximum thickness reduction and percent ADC change may be useful for predicting good responders in patients undergoing preoperative CRT for rectal cancer. Larger studies are warranted to establish the utility of PET/MRI in rectal cancer staging.

Risk of Stroke in Nasopharyngeal Cancer Survivors: A National Registry-Based Population Cohort Study.

BACKGROUND AND OBJECTIVES: We aim to determine the risk of stroke and death within 30 days after stroke in nasopharyngeal cancer (NPC) survivors. METHODS: We conducted a population-based cohort study of patients diagnosed with NPC from January 1, 2005, to December 31, 2017. Using the cancer and stroke disease registries and the Singapore general population as the reference population, we report the age-standardized incidence rate differences (SIRDs) ratios (SIRs) and the cumulative incidence of stroke and the standardized mortality rate differences (SMRDs) and ratios (SMRs) for all causes of death within 30 days after stroke for NPC survivors. RESULTS: At a median follow-up of 48.4 months (interquartile range 19.8-92.9 months) for 3,849 patients diagnosed with NPC, 96 patients developed stroke. The overall SIRD and SIR for stroke were 3.12 (95% confidence interval [CI] 2.09-4.15) and 2.54 (95% CI 2.08-3.10), respectively. The SIRD was highest for the age group 70 to 79 years old (8.84 cases per 1,000 person-years, 95% CI 0.46-17.21), while the SIR was highest for the age group 30 to 39 years old (16.41, 95% CI 6.01-35.82). The SIRD and SIR for stage 1 disease were (6.96 cases per 1000 person-years, 95% CI 2.16-11.77) and (4.15, 95% CI 2.46-7.00), respectively. The SMRD and SMR for all cause deaths within 30 days of stroke were (3.20 cases per 100 persons, 95% CI -3.87 to 10.28) and (1.34, 95% CI 0.76-2.37), respectively. DISCUSSION: The overall risk of stroke was markedly elevated in survivors of NPC, especially in stage 1 disease, compared to the general population. The risk of death within 30 days of stroke was not significantly higher for NPC survivors. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence of the increased risk of stroke in survivors of NPC compared to the general population.

Stereotactic body radiation therapy versus conventional external beam radiation therapy for painful bone metastases: A systematic review and meta-analysis of randomized trials.

PURPOSE: To compare the efficacy and safety of stereotactic body radiation therapy (SBRT) and conventional external beam radiation therapy (cEBRT) in patients with previously unirradiated painful bone metastases (BM). METHODS: We searched biomedical databases for eligible randomized controlled trials (RCTs). The outcomes of interest were pain response, local progression, overall survival (OS) and adverse events. We used established tools to assess the quality of the individual trials and certainty of the pooled evidence. We performed meta-analyses using random effects models. RESULTS: Six RCTs were identified. SBRT improved complete pain response rates at 3 months (OR, 3.38; 95% CI, 1.88-6.07; high certainty), reduced local progression rates (OR, 0.19; 95% CI, 0.06-0.62; high certainty) and increased pain flare rates. There were no differences for other outcomes. CONCLUSION: Among patients with previously unirradiated painful BM, SBRT significantly improved complete pain response rates at 3 months, delayed local progression and increased pain flare rates.

Use of the Cancer and Aging Research Group Predictive Model for Chemotherapy-Related Toxic Effects in a Multiethnic, Older Adult Asian Population.

Importance: The Cancer and Aging Research Group (CARG) prediction model for chemotherapy-related toxic effects has been developed but not yet validated in older Asian adults. In view of differences in drug metabolism and toxic effect reporting in the Asian population, the ability of this tool to guide the cancer treatment decision-making process in older Asian adults needs to be assessed. Objective: To examine the validity of the CARG predictive model in a multiethnic Asian cohort of older adults. Design, Setting, and Participants: In this prognostic study, patients of various Asian ethnicities 70 years or older with a solid tumor diagnosis receiving chemotherapy at the National University Cancer Institute, Singapore, were accrued from June 1, 2017, to January 1, 2019. Their risks of chemotherapy-related toxic effects were calculated using the CARG tool. A geriatric assessment was performed, and the treating oncologist (blinded to the CARG scores) was asked to give an estimated likelihood of toxic effects (low, medium, or high). Chemotherapy-related toxic effects were recorded during each clinic visit. Validation of the prediction model was performed by calculating the area under the receiver operating characteristic curve. Multivariate analyses were performed to identify variables in other domains in the geriatric assessment predicting for severe toxic effects. Main Outcomes and Measures: Grade 3 to 5 toxic effects and hospitalization. Results: The study included 200 patients (median age, 74 years [range, 70-89 years]; 110 [55.0%] male; 177 [88.5%] Chinese, 17 [8.5%] Malay, 4 [2.0%] Indian, and 2 [1.0%] other ethnicities [according to Singapore's national system of race classification]). A total of 137 patients (68.5%) experienced grade 3 to 5 toxic effects, and 131 (65.5%) required hospitalization. The area under the receiver operating characteristic curve for the CARG chemotoxicity prediction model was 0.74 (95% CI, 0.67-0.82), retaining good discrimination in the study population. Conclusions and Relevance: This prognostic study conducted in a multiethnic Asian cohort of older adults supports the validity of the CARG predictive model in this population, predicting which older adults are at risk of chemotherapy-related toxic effects.

Quantifying the changes in the tumour vascular micro-environment in spinal metastases treated with stereotactic body radiotherapy - a single arm prospective study.

BACKGROUND: The primary objective was to quantify changes in vascular micro-environment in spinal metastases (SM) patients treated with stereotactic body radiotherapy (SBRT) with multi-parametric dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI). The secondary objective was to study plasma biomarkers related to endothelial apoptosis. PATIENTS AND METHODS: Patients were imaged with DCE-MRI at baseline/1-week/12-weeks post-SBRT. Metrics including normalised time-dependent leakage (Ktrans), permeability surface product (PS), fractional plasma volume (Vp), extracellular volume (Ve) and perfusion (F) were estimated using distributed parameter model. Serum acid sphingomyelinase (ASM) and sphingosine-1-phosphate (S1P) were quantified using ELISA. Clinical outcomes including physician-scored and patient-reported toxicity were collected. RESULTS: Twelve patients (with varying primary histology) were recruited, of whom 10 underwent SBRT. Nine patients (with 10 lesions) completed all 3 imaging assessment timepoints. One patient died due to pneumonia (unrelated) before follow-up scans were performed. Median SBRT dose was 27 Gy (range: 24-27) over 3 fractions (range: 2-3). Median follow-up for alive patients was 42-months (range: 22.3-54.3), with local control rate of 90% and one grade 2 or higher toxicity (vertebral compression fracture). In general, we found an overall trend of reduction at 12-weeks in all parameters (Ktrans/PS/Vp/Ve/F). Ktrans and PS showed a reduction as early as 1-week. Ve/Vp/F exhibited a slight rise 1-week post-SBRT before reducing below the baseline value. There were no significant changes, post-SBRT, in plasma biomarkers (ASM/S1P). CONCLUSIONS: Tumour vascular micro-environment (measured by various metrics) showed a general trend towards downregulation post-SBRT. It is likely that vascular-mediated cell killing contributes to excellent local control rates seen with SBRT. Future studies should evaluate the effect of SBRT on primary-specific spinal metastases (e.g., renal cell carcinoma).

Booster doses of COVID-19 vaccines for patients with haematological and solid cancer: a systematic review and individual patient data meta-analysis.

IMPORTANCE: Patients with cancer have an increased risk of severe disease and mortality from COVID-19, as the disease and antineoplastic therapy cause reduced vaccine immunogenicity. Booster doses have been proposed to enhance protection, and efficacy data are emerging from several studies. OBJECTIVE: To evaluate the proportion of COVID-19 primary vaccination non-responders with cancer who seroconvert after a booster dose. METHODS: PubMed, EMBASE, CENTRAL and medRxiv were searched from 1st January 2021 to 10th March 2022. Quality was assessed using the Joanna Briggs Institute Critical Appraisal checklist. RESULTS: After the eligibility assessment, 22 studies were included in this systematic review and 17 for meta-analysis of seroconversion in non-responders, pooling a total of 849 patients with haematological cancer and 82 patients with solid cancer. Haematological cancer non-responders exhibited lower seroconversion at 44% (95% CI 36-53%) than solid cancer at 80% (95% CI 69-87%). Individual patient data meta-analysis found the odds of having a meaningful rise in antibody titres to be significantly associated with increased duration between the second and third dose (OR 1.02, 95% CI 1.00-1.03, P ≤ 0.05), age of patient (OR 0.960, 95% CI 0.934-0.987, P ≤ 0.05) and cancer type. With patients with haematological cancer as a reference, patients with lung cancer had 16.8 times the odds of achieving a meaningful increase in antibody titres (OR 16.8, 95% CI 2.95-318, P ≤ 0.05) and gastrointestinal cancer patients had 25.4 times the odds of achieving a meaningful increase in antibody titres (OR 25.4, 95% CI 5.26-492.21, P ≤ 0.05). CONCLUSIONS: administration of a COVID-19 vaccine booster dose is effective in improving seroconversion and antibody levels. Patients with haematological cancer consistently demonstrate poorer response to booster vaccines than patients with solid cancer.