Enhancing quality assurance in radiotherapy for gynaecological cancers: implementation of an on-demand peer review process.

OBJECTIVES: Ensuring high-quality radiotherapy requires peer-reviewing target volumes. The Royal College of Radiologists recommends peer review specifically for individual target volumes in cases of gynaecological cancers. This study presents the outcomes of implementing an on-demand peer review system for gynaecological cancers within our institute. METHODS: The peer review process was planned for gynaecological cancer cases intended for curative radiotherapy. After junior clinical oncologists (COs) completed the segmentation, two senior COs specializing in gynaecological cancers conducted the peer review. All peer review outcomes were recorded prospectively. The audit process compliance, the proportion of patients requiring major and minor modifications in target volumes, the direction of changes, and the factors influencing these changes were reported. RESULTS: A total of 230 patients were eligible, and out of these, 204 (88.3%) patients underwent at least one peer review. Among the patients, 108 required major modifications in their target volumes. P-charts revealed a stabilization in the need for major modifications at the end of three months, indicating that 38.2% and 28% of patients still required major modifications for the nodal and primary CTV, respectively. Multivariable analysis demonstrated that major modifications were associated with the use of extended field radiotherapy and radical radiation in non-cervical primary cases. CONCLUSIONS: An on-demand peer review system was feasible and resulted in clinically meaningful, major modifications in the target volumes for 53% of patients. ADVANCES IN KNOWLEDGE: Gynaecological cancers require ongoing peer review to ensure quality of care in radiotherapy. A flexible on-demand system not only ensures that patient treatment start is not delayed but also has an important educational role for junior trainees.

ICON-P - A double-blind evaluation of quality improvements with individualized CONstraints from low-cost knowledge-based radiation therapy planning in prostate cancer.

Purpose: /Objective(S)A low-cost, prior knowledge-based individualized dose-constraint generator for organs-at-risk has been developed for prostate cancer radiation therapy (RT) planning. In this study, we aimed to evaluate the feasibility and improvements in organs-at-risk (OAR) doses in prostate cancer RT planning using this tool served on a web application. Materials And Methods: A set of previously treated prostate cancer cases planned and treated with generic constraints were replanned using individualized dose constraints derived from a library of cases with similar volumes of target, OAR, and overlap regions and served on the web-based application. The goal was to assess the reduction in mean dose, specified dose volumes (V59Gy, V56Gy, V53Gy, V47Gy, and V40Gy), and generalized equivalent uniform dose (gEUD) to the rectum and bladder. Planners and assessors were blinded to the initial achieved doses and penalties. Sample size estimation was based on improvement in V53Gy for the rectum and bladder with a paired evaluation. Results: Twenty-four patients were replanned. All the plans had a PTV D95 of at least 97% of the prescribed dose. The individualized OAR constraints could be met for 87.5% of patients for all dose levels. The mean dose, V59Gy, V53Gy, and V47Gy for the bladder was reduced by 7.5 Gy, 1.12%, 5.51%, and 10.53% respectively. Similarly for the rectum, the mean dose, V59Gy, V53Gy, V47Gy and was reduced by 5.5 Gy, 4.34%, 6.97%, and 11.61% respectively. All dose reductions were statistically significant. The gEUD of the bladder was reduced by 2.47 Gy (p < 0.001) and the rectum by 3.21 Gy (p < 0.001). Conclusion: Treatment planning based on individualized dose constraints served on a web application is feasible and leads to improvement at clinically important dose volumes in prostate cancer RT planning. This application can be served publicly for improvements in RT plan quality.

Alleviating Morbidity From Locally Advanced Breast Cancer Using a Practical and Short Radiation Therapy Regimen: Results of the HYPORT Palliative Studies.

PURPOSE: Locally advanced breast cancers lead to debilitating local symptoms. Treatment of these women encountered commonly in less resourced countries is not backed by strong evidence. We formulated the  HYPORT and HYPORT B phase 1/2 studies to evaluate the safety and efficacy of hypofractionated palliative breast radiation therapy. METHODS AND MATERIALS: Two studies (35 Gy/10 fractions; HYPORT ) and (26 Gy to breast/32 Gy tumor boost in 5 fractions; HYPORT B) were designed with increasing hypofractionation to save overall treatment time from 10 to 5 days. We report the acute toxicity, symptomatic, metabolic response, and quality of life (QOL) changes after radiation therapy. RESULTS: Fifty-eight patients, the majority of whom were pretreated with systemic therapy, completed the treatment. No grade 3 toxicity was reported. Response assessment at 3 months showed improvement in ulceration (58% vs 22%, P = .013) and bleeding (22% vs 0%, P = .074) within the HYPORT study. Similarly, in the HYPORT B study, ulceration (64% and 39%, P = .2), fungating (26% and 0%, P = .041), bleeding (26% and 4.3%, P = .074), and discharge (57% and 8.7%, P = .003) was reduced. Metabolic response was noted in 90% and 83% of patients, respectively, in the 2 studies. Improvement in the QOL scores were evident in both studies. Only 10% of the patients relapsed locally within 1 year. CONCLUSIONS: Palliative ultrahypofractionated radiation therapy to the breast is well tolerated, is effective, and results in a durable response with improved QOL. This could be considered a standard for locoregional symptom control.

Evaluating Quality Indicators of Glioblastoma Care: Audit Results From an Indian Tertiary Care Cancer Center.

PURPOSE: There are limited reports of quality metrics in glioblastoma. We audited our adherence to quality indicators as proposed in the PRIME Quality Improvement study. METHODS: This is a retrospective audit of patients treated between 2017 and 2020. After postsurgical integrated diagnosis, patients received radiotherapy (RT) with concurrent and adjuvant temozolomide (TMZ). Multiparametric magnetic resonance imaging at predefined times guided management. Numbers with proportions for indices were calculated. Survival was estimated using the Kaplan-Meier method. RESULTS: One hundred six patients were consecutively treated. The median age was 55 years (interquartile range of 47-61 years) with a male preponderance (68%). Ninety-six (90.6%) patients underwent subtotal resection, and 10 (9.4%) biopsy alone. Isocitrate dehydrogenase was wild-type in 96 (91%), and O6-methylguanine-DNA methyltransferase was unmethylated in 70 (66.0%) patients. Telomerase reverse transcriptase promoter was mutated in 64 (60.4%), and TP53 was mutated in 22 (20.8%). Concurrent radiation and TMZ were planned for 104 (98.1%), and radiation alone for 2 (1.9%). The median time to concurrent RT-TMZ was 36 days (interquartile range 30-44 days). All patients planned for RT-TMZ completed treatment, but only 81 (76%) completed adjuvant TMZ. Sixty-three (59%) completed six cycles, 18 (17%) received less than six cycles, and 25 (24%) did not receive adjuvant TMZ. At a median follow-up of 24 months (range 21-31 months), the median (95% CI) progression-free survival and overall survival were 11 (95% CI, 9.4 to 13.0) and 20.0 (95% CI, 15 to 26) months, respectively. CONCLUSION: Our patients met quality indices in most domains; outcomes are comparable with global results. Metrics will be periodically evaluated to include new standards and assess continuous service appropriateness.

Design and Development of a Medical Image Databank for Assisting Studies in Radiomics.

CompreHensive Digital ArchiVe of Cancer Imaging - Radiation Oncology (CHAVI-RO) is a multi-tier WEB-based medical image databank. It supports archiving de-identified radiological and clinical datasets in a relational database. A semantic relational database model is designed to accommodate imaging and treatment data of cancer patients. It aims to provide key datasets to investigate and model the use of radiological imaging data in response to radiation. This domain of research area addresses the modeling and analysis of complete treatment data of oncology patient. A DICOM viewer is integrated for reviewing the uploaded de-identified DICOM dataset. In a prototype system we carried out a pilot study with cancer data of four diseased sites, namely breast, head and neck, brain, and lung cancers. The representative dataset is used to estimate the data size of the patient. A role-based access control module is integrated with the image databank to restrict the user access limit. We also perform different types of load tests to analyze and quantify the performance of the CHAVI databank.

Xerostomia quality of life and resource requirements following parotid sparing adaptive radiotherapy in head and neck cancers: Results of a prospective cohort study (Study ID CTRI/2017/11/010683).

BACKGROUND AND PURPOSE: Parotid sparing adaptive radiotherapy (PSART) is resource intensive to implement. Selection criteria for using ART and its impact on quality of life (QoL) is poorly reported. This has been addressed in our study. MATERIALS AND METHODS: Patients planned for curative radiotherapy for Head Neck Cancers were recruited following informed consent in a prospective cohort study. PSART was planned if the mean dose to index parotid(s) increased by 2% from the baseline approved plan. To assess the resource requirements of PSART manpower and time required for treatment planning both for initial as well as PSART was documented. Patient reported QoL using QualiXeQLS and EORTC QLQ C30 and HN35 were obtained pre radiotherapy, and at 3 and 9 months post radiotherapy. RESULTS: Of the ninety patients accrued, 87 were evaluable. 45 (51%) received PSART based on the prespecified criteria. The average time spent in contouring (276 min versus 133 min) and treatment planning (293 min versus 108 min) were almost doubled when PSART was implemented. XeQoL scores at 3 months were significantly worse in those receiving PSART (mean 2.3 vs 1.2, p 0.002). Despite this, xerostomia related QoL recovered to near baseline scores by 9 months after receiving PSART. CONCLUSION: Implementation of PSART is resource intensive. The proposed cutoff for implementing PSART identifies a higher risk population that have worse xerostomia related quality of life. This study lays the foundation for a randomized trial to determine the efficacy of PSART on xerostomia related QoL.

Can the CROSS protocol be safely implemented in real world scenario with broader eligibility criteria? Experience from a tertiary care centre in India.

BACKGROUND: The Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) trial established a new benchmark in the management of oesophageal cancer with neoadjuvant chemoradiation followed by surgery with a marked benefit for squamous cell carcinomas (SCCs). We evaluate if the CROSS protocol can be safely implemented with a broader eligibility criteria in a real-world setting. METHODS: A retrospective analysis of 80 patients of SCC oesophagus was performed, who were treated with neoadjuvant chemoradiation with radiation therapy (RT) to 41.4 Gy/23 Fr/4.5 weeks and weekly paclitaxel and carboplatin, followed by surgery at our institute between 2012 and 2019. Eligibility for the use of this regimen was expanded beyond the limits of size and stage allowed in the CROSS trial. RESULTS: The median age of this cohort was 57 years (range: 39-78 years). Most of the patients (77/80; 96.3%) had T3 disease and 25% patients (20/80) had N2/N3 disease. Thirty-three patients (41.3%) had the disease beyond CROSS eligibility criteria. All patients completed planned course of RT and five cycles of weekly chemotherapy were received by 61 patients (76.2%). Overall pathological complete response (pCR) could be achieved in 33 patients (41.3%). Among 33 CROSS ineligible patients, 14 (42.4%) had pCR. Acute grade 3 dysphagia and grade ≥ 3 neutropenia were seen in seven cases (8.3%) and nine cases (10.7%), respectively. At a median follow-up of 16 months, 1-year and 2-year overall survival (OS) were 84.4% (95% confidence interval (CI): 73.5%-91.1%) and 76.3% (95% CI: 63.2%-85.2%), respectively, for the entire cohort. For CROSS ineligible patients, 1-year and 2-year OS were 82% (95% CI: 61.8%-92.2%) and 72.7% (95% CI: 50.4%-86.2%), respectively. On univariate analysis, patients who had pathologically N0 disease had significantly better 2-year OS (85.7% versus 48.4%; p = 0.03) as compared to pathologically N+ patients. On univariate and multivariate analysis, there was no significant difference in OS and progression free survival between CROSS eligible and CROSS ineligible patients. CONCLUSION: CROSS protocol can be safely implemented for carefully selected patients of SCC oesophagus outside clinical trial settings with expanded eligibility criteria.

Real-world results of definitive chemoradiation in carcinoma oesophagus: can SCOPE1 results be replicated outside trial setting?

BACKGROUND: Definite concurrent chemoradiation is the standard of care for locally advanced unresectable oesophageal cancers. However, heterogeneity exists in the practice of concurrent chemoradiation approaches. Here we describe the efficacy and toxicities of the standard arm of SCOPE1 protocol implemented at our institute. METHODS: Treatment records of 36 patients with unresectable oesophageal cancers treated with concurrent chemoradiation between January 2015 and June 2019 were audited. Treatment was based on the standard arm of SCOPE1 protocol (neoadjuvant and concurrent platinum and capecitabine with external beam radiation to a dose of 50 Gy/25 fractions/5 weeks). The electronic hospital information system and oncology information system were queried to obtain information on patient characteristics and treatment delivery patterns. RESULTS: Out of 36 patients, 35 had squamous cell carcinomas. 25% of the patients (9/36) were 70 years or older. 66.7% of patients (24/36) had T4 disease, and 16 (44.4%) had N2-N3 nodal disease at presentation. A total of 30 patients (83.3%) could not undergo surgery because of the location and locoregional extent of the disease. The median follow-up of the entire cohort and the surviving patients was 10 months (range 3-51 months) and 13 months (range 4-51 months), respectively. The median overall survival (OS) of the entire cohort was 28 months. The 2-year local progression-free survival and OS were 71.2% (95% CI: 48.5%-85.3%) and 57.4% (95%CI: 29.6%-77.6%), respectively. Commonly observed acute Grade 3 toxicities were dysphagia (22.2%) and thrombocytopenia (19.4%). CONCLUSION: The outcomes of the SCOPE1 protocol have been validated for the first time in a different geographical, racial and ethnic population. Implementation of the standard arm of SCOPE1 protocol is feasible in our setting with acceptable adverse effects and good treatment compliance. Results are comparable to the results of the published trial.

Intensity modulated radiotherapy in anal canal squamous cell carcinoma: Implementation and outcomes.

OBJECTIVE: Concurrent chemoradiotherapy (CCRT) is the standard curative treatment option for nonmetastatic anal squamous cell carcinoma (SCC). Intensity modulated radiotherapy (IMRT) can reduce doses delivered to bowel and skin and reduce toxicities associated with conventional fields. Here, we present our institutional data on dosimetry, toxicity, and clinical outcomes with IMRT for anal cancer. MATERIALS AND METHODS: We analyzed 23 patients of anal SCC treated with curative-intent CCRT/radiation therapy alone, utilizing IMRT, between August 2011 and December 2016. The standard prescription dose was 54 Gy/27Fr/5.5 weeks, delivered in two phases, and concurrent chemotherapy with 5-fluorouracil and mitomycin-C. Acute and late toxicities and dosimetric data were compiled and analyzed. RESULTS: The median age was 65 years. Fourteen (60.7%) patients had Stage IIIC disease. Eighteen patients received concurrent chemotherapy. No patient had any treatment breaks. Grade 3 acute perianal dermatitis was recorded in 11 (47.8%) patients. Proctitis, diarrhea, and cystitis were limited to Grade 1 in 73.9%, 47.8%, and 8.6% patients, respectively. The only late Grade 2+ toxicities were gastrointestinal toxicities in 4 (17.4%) patients. Twenty (87%) patients had complete response at 6 months. The 3-year local control, nodal control, and distant metastases-free survival were 85.9%, 86.6%, 84.7%, respectively, with 3-year disease-free survival and overall survival of 63.4% and 81%, respectively. CONCLUSION: In this report on IMRT in anal cancer from India, treatment was well tolerated with lower acute toxicity than reported in other prospective studies. Long-term results are at par with other published studies.

Research Goal-Driven Data Model and Harmonization for De-Identifying Patient Data in Radiomics.

There are various efforts in de-identifying patient's radiation oncology data for their uses in the advancement of research in medicine. Though the task of de-identification needs to be defined in the context of research goals and objectives, existing systems lack the flexibility of modeling data and normalization of names of attributes for accomplishing them. In this work, we describe a de-identification process of radiation and clinical oncology data, which is guided by a data model and a schema of dynamically capturing domain ontology and normalization of terminologies, defined in tune with the research goals in this area. The radiological images are obtained in DICOM format. It consists of diagnostic, radiation therapy (RT) treatment planning, RT verification, and RT response images. During the DICOM de-identification, a few crucial pieces of information are taken about the dataset. The proposed model is generic in organizing information modeling in sync with the de-identification of a patient's clinical information. The treatment and clinical data are provided in the comma-separated values (CSV) format, which follows a predefined data structure. The de-identified data is harmonized throughout the entire process. We have presented four specific case studies on four different types of cancers, namely glioblastoma multiforme, head-neck, breast, and lung. We also present experimental validation on a few patients' data in these four areas. A few aspects are taken care of during de-identification, such as preservation of longitudinal date changes (LDC), incremental de-identification, referential data integrity between the clinical and image data, de-identified data harmonization, and transformation of the data to an underlined database schema.

A Web-based Dose-volume Histogram Dashboard for Library-based Individualized Dose-constraints and Clinical Plan Evaluation.

Traditional methods of treatment planning and plan evaluation involve the use of generic dose-constraints. We aimed to build a web-based application to generate individualized dose-constraints and plan evaluation against a library of prior approved plan dose-volume histograms (DVH).A prototype was built for intensity modulated radiation therapy (IMRT) plans for prostate cancer. Using exported DVH files from the Varian and Accuray treatment planning systems, a library of plan DVHs was built by data extraction. Given structure volumes of a patient to be planned, a web based application was built to derive individual dose-constraints of the planning target volume (PTV) and organs-at-risk (OAR) based on achieved doses in a library of prior approved plans with similar anatomical volumes, selected using an interactive dashboard. A second web application was built to compare the achieved DVHs of the newly created plan against a library of plans of similar patients.These web application prototypes are a proof of principle that simple freely available tools can be built for library based planning and review.

Geographic disparities in access to cancer clinical trials in India.

INTRODUCTION: The current study was aimed at quantifying the disparity in geographic access to cancer clinical trials in India. METHODS: We collated data of cancer clinical trials from the Clinical Trial Registry of India and data on state-wise cancer incidence from the Global Burden of Disease Study. The total sample size for each clinical trial was divided by the trial duration to get the sample size per year. This was then divided by the number of states in which accrual was planned to get the sample size per year per state (SSY).For interventional trials investigating a therapy, the SSY was divided by the number of incident cancers in the state to get the SSY per 1,000 incident cancer cases. The SSY data was then mapped to visualise the geographical disparity. RESULTS: We identified 181 ongoing studies, of which 132 were interventional studies. There was a substantial inter-state disparity-with a median SSY of 1.55 per 1,000 incident cancer cases (range 0.00-296.81 per 1,000 incident cases) for therapeutic interventional studies. Disparities were starker when cancer site-wise SSY was considered. Even in the state with the highest SSY, only 29.7% of the newly diagnosed cancer cases have an available slot in a therapeutic cancer clinical trial. Disparities in access were also apparent between academic (range: 0.21-226.60) and industry-sponsored trials (range: 0.17-70.21). CONCLUSION: There are significant geographic disparities in access to cancer clinical trials in India. Future investigations should evaluate the reasons and mitigation approaches for such disparities.

Prioritizing Delivery of Cancer Treatment During a COVID-19 Lockdown: The Experience of a Clinical Oncology Service in India.

PURPOSE: A COVID-19 lockdown in India posed significant challenges to the continuation of radiotherapy (RT) and systemic therapy services. Although several COVID-19 service guidelines have been promulgated, implementation data are yet unavailable. We performed a comprehensive audit of the implementation of services in a clinical oncology department. METHODS: A departmental protocol of priority-based treatment guidance was developed, and a departmental staff rotation policy was implemented. Data were collected for the period of lockdown on outpatient visits, starting, and delivery of RT and systemic therapy. Adherence to protocol was audited, and factors affecting change from pre-COVID standards analyzed by multivariate logistic regression. RESULTS: Outpatient consults dropped by 58%. Planned RT starts were implemented in 90%, 100%, 92%, 90%, and 75% of priority level 1-5 patients. Although 17% had a deferred start, the median time to start of adjuvant RT and overall treatment times were maintained. Concurrent chemotherapy was administered in 89% of those eligible. Systemic therapy was administered to 84.5% of planned patients. However, 33% and 57% of curative and palliative patients had modifications in cycle duration or deferrals. The patient's inability to come was the most common reason for RT or ST deviation. Factors independently associated with a change from pre-COVID practice was priority-level allocation for RT and age and palliative intent for systemic therapy. CONCLUSION: Despite significant access limitations, a planned priority-based system of delivery of treatment could be implemented.

De-Identification of Radiomics Data Retaining Longitudinal Temporal Information.

We propose a de-identification system which runs in a standalone mode. The system takes care of the de-identification of radiation oncology patient's clinical and annotated imaging data including RTSTRUCT, RTPLAN, and RTDOSE. The clinical data consists of diagnosis, stages, outcome, and treatment information of the patient. The imaging data could be the diagnostic, therapy planning, and verification images. Archival of the longitudinal radiation oncology verification images like cone beam CT scans along with the initial imaging and clinical data are preserved in the process. During the de-identification, the system keeps the reference of original data identity in encrypted form. These could be useful for the re-identification if necessary.

Incidence and patterns of retropharyngeal lymph node involvement in oropharyngeal carcinoma.

INTRODUCTION: The aim was to evaluate in oropharyngeal carcinoma the: (1) incidence and predictors of retropharyngeal (RP) lymph node (LN) involvement, (2) pattern of ipsilateral/bilateral/contralateral-only RP LNs (3) location of RP LNs in relation to contouring guidelines. METHODS: Single centre retrospective analysis of 402 patients with oropharyngeal carcinoma treated non-surgically between 2010 and 2017. All patients had a baseline FDG PET-CT and contrast-enhanced MRI and/or CT. All cases with reported abnormal RP LNs underwent radiology review. RESULTS: Abnormal RP LNs were identified in 40/402 (10%) of patients. On multivariate analysis, RP LN involvement was associated with posterior pharyngeal wall/soft palate primaries (OR 10.13 (95% CI 2.29-19.08), p = 0.002) and contralateral cervical LN involvement (OR 2.26 (95% CI 1.05-4.86), p = 0.036). T stage, largest LN size, levels of ipsilateral LN level involvement, HPV and smoking status did not predict risk. 5/402 (1.2%) patients had bilateral RP involvement. 3/402 patients (0.7%) had contralateral-only RP LNs. All patients with contralateral RP LNs had contralateral neck nodes or primary cancers extending across midline. In 5/40 (12.5%) cases with involved RP LNs, the RP LNs were superior to hard palate/upper edge of body of C1 vertebra. CONCLUSIONS: RP LNs were identified in 10% of oropharyngeal carcinoma patients, and were associated with contralateral neck disease and/or posterior pharyngeal wall/soft palate primary. Contralateral RP LN involvement was rare and associated with contralateral neck disease and/or primary crossing midline, suggesting potential for omission from target volumes for selected patients. Involvement of RP LNs close to the skull base highlights the need for generous elective outlining.

Second-look PET-CT following an initial incomplete PET-CT response to (chemo)radiotherapy for head and neck squamous cell carcinoma.

OBJECTIVES: The limited positive predictive value of an incomplete response on PET-CT following (chemo)radiotherapy for head and neck squamous cell carcinoma (HNSCC) means that the optimal management strategy remains uncertain. The aim of the study is to assess the utility of a 'second-look' interval PET-CT. METHODS: Patients with HNSCC who were treated with (chemo)radiotherapy between 2008 and 2017 and underwent (i) baseline and (ii) response assessment PET-CT and (iii) second-look PET-CT following incomplete (positive or equivocal scan) response were included. Endpoints were conversion rate to complete response (CR) and test characteristics of the second-look PET-CT. RESULTS: Five hundred sixty-two patients with HNSCC underwent response assessment PET-CT at a median of 17 weeks post-radiotherapy. Following an incomplete response on PET-CT, 40 patients underwent a second-look PET-CT at a median of 13 weeks (range 6-25) from the first response PET-CT. Thirty-four out of 40 (85%) patients had oropharyngeal carcinoma. Twenty-four out of 40 (60%) second-look PET-CT scans converted to a complete locoregional response. The primary tumour conversion rate was 15/27 (56%) and the lymph node conversion rate was 14/19 (74%). The sensitivity, specificity, positive predictive value and negative predictive value (NPV) of the second-look PET-CT were 75%, 75%, 25% and 96% for the primary tumour and 100%, 92%, 40% and 100% for lymph nodes. There were no cases of progression following conversion to CR in the primary site or lymph nodes. CONCLUSIONS: The majority of patients who undergo a second-look PET-CT convert to a CR. The NPV of a second-look PET-CT is high, suggesting the potential to avoid surgical intervention. KEY POINTS: • PET-CT is a useful tool for response assessment following (chemo)radiotherapy for head and neck squamous cell carcinoma. • An incomplete response on PET-CT has a limited positive predictive value and optimal management is uncertain. • These data show that with a 'second-look' interval PET-CT, the majority of patients convert to a complete metabolic response. When there is doubt about clinical and radiological response, a 'second-look' PET-CT can be used to spare patients unnecessary surgical intervention.

Retropharyngeal Lymph Node Involvement in Oropharyngeal Carcinoma: Impact upon Risk of Distant Metastases and Survival Outcomes.

The influence of retropharyngeal lymph node (RPLN) involvement on prognosis in oropharyngeal carcinoma remains poorly defined. The aim of this study was to assess the impact of RPLN involvement upon outcomes. A single-centre retrospective analysis of 402 patients with oropharyngeal carcinoma treated nonsurgically between 2010 and 2017 was performed. All had a baseline 2-[fluorine-18]-fluoro-2-deoxy-d-glucose (FDG) PET-CT and contrast-enhanced MRI and/or CT. RPLN status was determined by radiology review of cases with reported abnormal RPLN. Multivariate backwards logistic regression was used to examine impact on outcomes of factors. Abnormal RPLNs were identified in 40/402 (10%) of patients. Median follow up was 42.9 months. RPLN involvement was associated with inferior 3 year outcomes for overall survival (OS) (67.1% vs. 79.1%, p = 0.006) and distant metastases-free survival (DMFS) (73.9% versus 88.0%, p = 0.011), with no significant difference in local control (81.6% vs. 87.7%, p = 0.154) or regional control (80.7% vs. 85.4%, p = 0.252). On multivariate analysis abnormal RPLN, no concurrent chemotherapy and ongoing smoking were associated with inferior DMFS and OS, while advanced T stage was also associated with inferior OS. In summary, RPLN involvement, present in 10% of patients, was an independent prognostic factor for the development of distant disease failure translating into inferior OS. These findings need confirmation in future studies.

Acute toxicity and its dosimetric correlates for high-risk prostate cancer treated with moderately hypofractionated radiotherapy.

AIMS: To report the acute toxicity and the dosimetric correlates after moderately hypofractionated radiotherapy for localized prostate cancer. METHODS: A total of 101 patients with localized prostate cancer were treated with image-guided intensity-modulated radiation therapy. Patients were treated to 65Gy/25Fr/5 weeks (n = 18), or 60Gy/20Fr/4 weeks (n = 83). Most (82.2%) had high-risk or pelvic node-positive disease. Acute toxicity was assessed using Radiation Therapy Oncology Group (RTOG) acute morbidity scoring criteria. Dose thresholds for acute rectal and bladder toxicity were identified. RESULTS: The incidence of acute grade 2 GI toxicity was 20.8%, and grade 2 genitourinary (GU) toxicity was 6.9%. No Grade 3 to 4 toxicity occurred. Small bowel toxicity was uncommon (Gr 2 = 4%). The 2Gy equivalent doses (EQD2) to the rectum and bladder (α/ß = 3) calculated showed that the absolute doses were more consistent predictors of acute toxicities than the relative volumes. Those with grade 2 or more GI symptoms had significantly higher VEQD2-60Gy (13.2 vs 9.9cc, p = 0.007) and VEQD2-50Gy (20.6 vs 15.4cc, p = 0.005). Those with grade 2 or more GU symptoms had significantly higher VEQD2-70Gy (30.4 vs 18.4cc, p = 0.001) and VEQD2-65Gy (44.0 vs 28.8cc, p = 0.001). The optimal cutoff value for predicting grade 2 acute proctitis, for VEQD2-60Gy was 9.7cc and for VEQD2-50Gy was 15.9cc. For grade 2 GU symptoms, the threshold values were 23.6cc for VEQD2-70Gy and 38.1cc for VEQD2-65Gy. CONCLUSIONS: Hypofractionated radiotherapy for prostate cancer is well tolerated and associated with manageable acute side effects. The absolute dose-volume parameters of rectum and bladder predict for acute toxicities.