Radiation Oncology Training in the Philippines: Bridging Gaps for Improved Cancer Care in Low- and Middle-Income Countries.

PURPOSE: Radiation oncology in the Philippines, a large lower- and middle-income country in Southeast Asia, is facing a critical shortage in manpower, with only 113 radiation oncologists (ROs) over 55 radiotherapy (RT) centers serving 100 million population. Paramount to workforce expansion is ensuring that training programs can produce adequately trained specialists. In this study, we describe the current state of radiation oncology training programs in the Philippines. METHODS: This is a cross-sectional observational analysis of the nine radiation oncology residency training programs in the Philippines. Data were collected from a survey of the program directors, the Philippine Radiation Oncology Society database, and a PubMed literature search. RESULTS: Eight of the nine programs are in the National Capital Region. Since program standardization in 2005, there have been 82 four-year residency graduates, with up to 18 new graduates annually. Faculty-to-trainee ratio ranges from 0.5 to 2.67. In terms of technology, all programs have intensity-modulated RT and high-dose-rate brachytherapy, but only six are equipped with computed tomography-based image guidance and stereotactic capabilities. Clinical education schemes vary per institution regarding curriculum implementation, resident activities, and methods of evaluation. Required resident case logs are not met for lung, GI, genitourinary, bone and soft tissue, and hematologic malignancies. In total, there are only 22 resident-led publications from 10 unique individuals in two training programs. CONCLUSION: Program expansions are warranted to meet the projected demand for ROs in the Philippines, but training programs must first improve key aspects of staffing, technology, clinical education, and research. Addressing training challenges related to resource limitations necessitates local and international collaborations with higher-capacity centers to bridge gaps for continued quality improvement with the aim of ultimately delivering better overall cancer care.

Proton therapy in Asia Pacific: current resources, international disparities and steps forward.

The burden of cancer in Asia Pacific, a region home to over four billion people, is growing. Because of sheer demographics alone, the Asia Pacific region arguably has the highest number of patients who can benefit from protons over conventional x-rays. However, only 39 out of 113 proton facilities globally are in Asia Pacific, and 11 of them are in low- and middle-income countries where 95% of the regional population reside. We draw attention to present resource distribution of proton therapy in Asia Pacific, highlight disparities in access, and suggest steps forward.

Significance of saline nasalirrigation for COVID-19 infection: observations and reflections from nursing care of nasopharyngeal carcinoma.

Background: Coronavirus disease 2019 (COVID-19) has placed a tremendous burden on the world's healthcare systems, prompting medical professionals worldwide to diligently research and experiment with treatment methods to prevent infection and alleviate symptoms. Previous studies have shown the potential of nasal irrigation in reducing viral clearance time and alleviating local symptoms of COVID-19. However, views differ regarding its efficacy in improving systemic symptoms. Thus, we sought to examine whether saline nasal irrigation might play a role in treatment and self-care after COVID-19 infection, but further validation is still necessary. Methods: We conducted a retrospective analysis of 468 patients and 51 healthcare personnel concurrently. The participants were grouped based on whether they received saline nasal irrigation. We used χ2 tests and Fisher's exact tests to assess the differences in the rates of COVID-19 infection and the rates of developing a fever after COVID-19 infection among different groups. Additionally, we used independent samples t-tests and Mann-Whitney U tests to evaluate differences in the maximum fever temperature and fever duration among participants with fever in different groups. Results: The rate of developing a fever after COVID-19 infection was lower (37.7%) in the patients who underwent saline nasal irrigation. Among all febrile patients, there was no difference in the highest fever temperature, but patients who underwent saline nasal irrigation had a shorter fever duration (1.72±1.05 days). Additionally, the rate of COVID-19 infection and the rate of developing a fever were higher, and fever symptoms were more severe in the healthcare worker group than in the patient group. Conclusions: Saline nasal irrigation can alleviate symptoms caused by COVID-19 infection.

Predictive accuracy of machine learning for radiation-induced temporal lobe injury in nasopharyngeal carcinoma patients: a systematic review and meta-analysis.

Background: Radiotherapy is a common treatment for nasopharyngeal carcinoma (NPC) but can cause radiation-induced temporal lobe injury (RTLI), resulting in irreversible damage. Predicting RTLI at the early stage may help with that issue by personalized adjustment of radiation dose based on the predicted risk. Machine learning (ML) models have recently been used to predict RTLI but their predictive accuracy remains unclear because the reported concordance index (C-index) varied widely from around 0.31 to 0.97. Therefore, a meta-analysis was needed. Methods: The PubMed, Web of Science, Embase, and Cochrane Library databases were searched from inception to November 2022. Studies that fully develop one or more ML risk models of RTLI after radiotherapy for NPC were included. The Prediction model Risk Of Bias Assessment Tool (PROBAST) was used to assess the risk of bias in the included research. The primary outcome of this review was the C-index, specificity (Spe), and sensitivity (Sen). Results: The meta-analysis included 14 studies with 15,573 NPC patients reporting a total of 72 prediction models. Overall, 94.44% of models were found to have a high risk of bias. Radiomics was included in 57 models, dosimetric predictors in 28, and clinical data in 27. The pooled C-index for ML models predicting RTLI was 0.77 [95% confidence interval (CI): 0.75-0.79] in the training set and 0.78 (95% CI: 0.75-0.81) in the validation set. The pooled Sen was 0.75 (95% CI: 0.69-0.80) in the training set and 0.70 (95% CI: 0.66-0.73) in the validation set and the pooled Spe was 0.78 (95% CI: 0.73-0.82) in the training set and 0.79 (95% CI: 0.75-0.82) in the validation set. Models with radiomics and clinical data achieved the most excellent discriminative performance, with a pooled C-index of 0.895. Conclusions: ML models can accurately predict RTLI at an early stage, allowing for timely interventions to prevent further damage. The kind of ML methods and the selection of predictors may influence the predictive accuracy.

Abnormal variation and prognostic significance of circulating immune cells in patients with nasopharyngeal carcinoma treated with chemoradiotherapy: a prospective cohort study.

Background: Circulating immune cells are associated with tumor development and poor prognosis in multiple solid tumors. However, the circulating immune-cell profile of nasopharyngeal carcinoma (NPC) remains largely unknown. Therefore, we aimed to determine the changes in immune status and the prognostic significance of circulating immune cells before and after chemoradiotherapy (CRT) in patients, which can provide clinicians with valuable insights to optimize treatment strategies, monitor immune function, and personalize interventions, ultimately improving patient outcomes. Methods: Circulating immune cells before and after CRT in 77 patients with NPC and in 30 healthy controls were measured with flow cytometry. A thorough follow-up was conducted to assess prognosis outcomes, including local failure-free rate (LFFR), distant failure-free rate (DFFR), disease-free survival (DFS), and overall survival (OS). The differences of the subpopulation distribution in the two groups were determined by t-tests or Mann-Whitney tests. The paired t-test or Wilcoxon matched-pairs signed rank test was used to compare differences in lymphocyte subsets before and after CRT. The prognostic significance of lymphocyte subsets was evaluated by Kaplan-Meier analysis and Cox proportional hazards model. Results: Compared with the control group, the NPC group showed significant decreases in the proportions of CD3+ cells, CD4+ T cells, CD8+CD28+ T cells, and CD19+ B cells as well as the CD4+:CD8+ ratio (P<0.05) but a significant increase in the proportion of natural killer (NK) cells (P<0.05). After CRT, the proportions of CD4+ cells, CD8+CD28+ T cells, and CD19+ B cells as well as the CD4+:CD8+ ratio were markedly decreased (P<0.05), while the proportions of CD8+ T cells and NK cells were significantly increased (P<0.05). Multivariate analysis showed that a lower percentage of CD19+ B cells [hazard ratio (HR) 6.550, 95% CI: 1.661-25.831; P=0.007] and a positive test for Epstein-Barr virus (EBV) DNA (HR 0.261, 95% CI: 0.074-0.926; P=0.038) before treatment independently predicted worse 5-year OS (P<0.05). Conclusions: The disproportion of circulating immune cells was observed in patients with NPC before treatment. CRT further aggravated immune dysfunction. Notably, a lower percentage of CD19+ B cells and EBV DNA-positive status before treatment were independent predictors of a worse prognosis. Thus, the measurement of circulating immune cells may help elucidate immune function status and predict the outcomes of patients with NPC.

The Role of postoperative external beam radiotherapy for differentiated thyroid carcinoma: A Systematic review and meta-analysis.

The indications for external beam radiotherapy (RT) in differentiated thyroid carcinomas (DTC) are still undefined. The objective of this study was to synthesize current evidence defining the role of postoperative RT in patients with DTC. A systematic review and meta-analysis were done. Included studies compared oncologic outcomes and toxicity of RT vs no RT in patients with DTC. Nine studies were included, two prospective and seven retrospective cohorts. RT improved 5-year locoregional recurrence-free survival but not overall survival and distant metastasis failure-free survival. The locoregional control benefit was seen in patients at increased risk for recurrence, including those with advanced age, locoregionally advanced disease, gross or microscopic residual tumor, and structural invasion. Serious RT-related acute and late toxicities were rare. Available evidence suggests that postoperative RT can improve locoregional control in high-risk DTC with acceptable toxicity. Further prospective studies are warranted.

Reirradiation for Recurrent Nasopharyngeal Carcinomas: Experience From an Academic Tertiary Center in a Low- to Middle-Income Country.

PURPOSE: The objectives of this study were to report the oncologic outcomes and the treatment-related toxicities after reirradiation (re-RT) for recurrent nasopharyngeal carcinoma (rNPC) at our institution and to apply a recently published prognostic model for survival in rNPC in our cohort. PATIENTS AND METHODS: Thirty-two patients with rNPC treated at the authors' institution with re-RT were retrospectively reviewed. Treatment modalities for re-RT were intensity-modulated radiotherapy (n = 14), three-dimensional conformal radiotherapy (n = 9), single-fraction stereotactic radiosurgery (n = 6), fractionated stereotactic radiotherapy (n = 2), and high dose rate intracavitary brachytherapy (n = 1). Twenty-seven patients received re-RT with curative intent, whereas five patients were treated palliatively. RESULTS: Median follow-up time was 15.5 months (range, 1 to 123 months) for the entire cohort and 20 months (range, 3 to 123 months) for patients treated with curative intent. For the entire cohort, median locoregional recurrence-free survival (LRRFS) was 14 months, with actuarial 1- and 2-year LRRFS estimates of 67.5% and 44.0%, respectively. Median overall survival (OS) time was 38 months, with actuarial 1- and 2-year estimates of 74.2% and 57.2%, respectively. For patients treated with curative intent, median LRRFS was not reached. Actuarial 1- and 2-year LRRFS estimates were 68.2% and 54.5%, respectively. Median OS time after curative intent re-RT was 42 months, with actuarial 1- and 2-year estimates of 75.4% and 63.8%, respectively. One- and 2-year OS estimates based on risk stratification were 68.6% for high risk compared with 80.8% for low risk and 34.3% for high risk compared with 70.7% for low risk, respectively ( P = .223). Three patients (9.4%) developed symptomatic temporal lobe necrosis. There was no reported grade 5 treatment-related toxicity. CONCLUSION: Results of the study suggest that re-RT is an effective and safe salvage treatment strategy for rNPC. Re-RT to a maximum equivalent dose in 2-Gy fractions of 60 Gy may yield good LRRFS and translate to prolonged OS.

Evidence on Effectiveness of Upper Neck Irradiation Versus Whole Neck Irradiation as Elective Neck Irradiation in Node-Negative Nasopharyngeal Cancer: A Meta-Analysis.

PURPOSE: Nasopharyngeal carcinoma (NPC) is a central tumor with a rich lymphatic network and a propensity for bilateral cervical lymph node metastasis. There is an orderly pattern of lymph node involvement in NPC. There is no current standard for prophylactic neck irradiation in node-negative or limited retropharyngeal (RP) node-positive NPC. This study aims to synthesize the current evidence on upper neck irradiation (UNI) versus whole neck irradiation (WNI) as prophylactic neck irradiation in node-negative or limited RP node-positive NPC. MATERIALS AND METHODS: A search of relevant articles was done from 2000 to October 2015. Critical appraisal and meta-analysis of the eligible studies were undertaken to assess the effectiveness of UNI versus WNI as prophylactic neck irradiation in node-negative or limited involved RP node NPC. RESULTS: Only one randomized controlled trial investigated the use of prophylactic UNI versus WNI and showed no confirmed nodal relapse in both arms. Pooled analysis of four retrospective studies showed no significant difference in nodal recurrence, whether in-field or out-of-field recurrence. There was also no significant difference in terms of 5-year distant metastasis-free and overall survival. CONCLUSION: In node-negative or limited RP node-positive NPC, the current evidence shows the possibility of treating only the upper neck (levels II, III, and VA) without compromising nodal control, distant metastasis, and overall survival. As a result of the scarcity of data, more randomized clinical trials are warranted in this subset of patients.

Interfraction Variation and Dosimetric Changes in Patients With Cervical Cancer Treated With Intracavitary Brachytherapy.

PURPOSE: Intracavitary brachytherapy is integral in the treatment of cervical cancer. Because of interfraction variation, the current standard is replanning with every fraction. This study aimed to determine whether there was a difference in relative dosimetry if the source position and dwell time of the first fraction were applied to subsequent fractions. MATERIALS AND METHODS: The authors performed a retrospective review of charts and films from 2007 to 2012. Eligible cases were patients with cervical cancer treated with brachytherapy with the same dose prescription to point A. Replanning was done on the first set of orthogonal plates. Source position and dwell time were subsequently applied to the remaining fractions using actual films. RESULTS: Twenty-nine patients were included in this study. The results showed that cervical, rectal, and bladder dose between the actual plan and the hypothetical plan were not statistically different. In the hypothetical plan, the source activity and dwell time of the first plan were applied to the orthogonal films of the subsequent fractions and showed no significant difference in all dose points. CONCLUSION: The results of this study showed proof of concept of the safety of using the source position and dwell time of the first plan for subsequent fractions. Until further studies are performed (also using three-dimensional planning software), the concept should be considered investigational because of the small sample size of the study. Until such research is performed, it is still strongly recommended that replanning be performed with every fraction whenever it is feasible.

A novel applicator design for intracavitary brachytherapy of the nasopharynx: Simulated reconstruction, image-guided adaptive brachytherapy planning, and dosimetry.

PURPOSE: In nasopharyngeal cancer, brachytherapy is given as boost in primary treatment or as salvage for recurrent or persistent disease. The Rotterdam nasopharyngeal applicator (RNA) allows for suboptimal reduction of soft palate radiation dose, based on image-guided brachytherapy plans. Building on the RNA, we propose a novel design, the Benavides nasopharyngeal applicator (BNA). METHODS AND MATERIALS: The virtual BNA was reconstructed on two cases (one T1, one T2) previously treated with intracavitary brachytherapy using the RNA. Dose was prescribed to the high-risk clinical target volumes (CTVs) and optimization was such that high-risk CTV D90 ≥ 100% of prescribed dose (PD), intermediate-risk-CTV D90 ≥ 75% PD, and soft palate D2cc ≤ 120% PD. The optimized RNA and BNA image-guided brachytherapy plans were compared in terms of CTV coverage and organs-at-risk sparing. RESULTS: Optimization objectives were more easily met with the BNA. For the T1 case, all three planning objectives were easily achieved in both the RNA and BNA, but with 18-19% lower soft palate doses with the BNA. For the T2 case, the CTV planning objectives were achieved in both the RNA and BNA, but the soft palate constraint was only achieved with the BNA, with 38-41% lower soft palate doses. CONCLUSIONS: Compared to the RNA, the BNA permits easier optimization and improves therapeutic ratio by a significant reduction of soft palate doses, based on simulation using a proposed system for CTV/organs-at-risk delineation, prescription, and optimization for image-guided adaptive brachytherapy. Clinical piloting using a prototype is necessary to evaluate its feasibility and utility.

Effectiveness of honey on radiation-induced oral mucositis, time to mucositis, weight loss, and treatment interruptions among patients with head and neck malignancies: A meta-analysis and systematic review of literature.

BACKGROUND: Mucositis is a disabling effect of radiotherapy in head and neck cancers. There is no current standard on management of radiation-induced mucositis. Honey has been shown to reduce radiation-induced mucositis. METHODS: A systematic review and meta-analysis were undertaken to assess the ability of honey in reducing the severity of oral mucositis, time to mucositis, weight loss, and treatment interruptions. RESULTS: Eight studies were included and showed that honey was significantly better in lowering the risk for treatment interruptions, weight loss, and delaying time to mucositis, but not severity of mucositis. CONCLUSION: There is current evidence that honey is beneficial for patients with head and neck cancers by decreasing treatment interruptions, weight loss, and delaying the onset of oral mucositis, but not in decreasing peak mucositis score. In light of the results, honey is a reasonable treatment for radiation-induced mucositis, but more randomized clinical trials (RCTs) should be done. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1119-1128, 2016.

Preliminary assessment of nasopharyngeal carcinoma incidence in the Philippines: a second look at published data from four centers.

In endemic regions such as southern China and Southeast Asia, the annual incidence of nasopharyngeal carcinoma (NPC) ranges from 3 to 30 per 100,000. In the Philippines, the estimated incidence in 2010 was 1.2 per 100,000. However, this rate is based on data collected from registries covering only two regions in the country. Here, we report the findings from our study to better approximate the incidence of NPC in the Philippines. Between September 1, 2011 and August 31, 2012, data were collected from 49 patients from 4 different institutions-University of Santo Tomas, Makati Medical Center, Philippine Oncology Center Corporation, and Cardinal Santos Memorial Medical Center-using a NPC screening questionnaire. Crude incidence was 0.09 per 100,000. Age-standardized incidences using Segi and WHO standards were 2.08 and 1.79 per 100,000, respectively. Of the 49 patients, 31 were males and 18 were females, and 71% of patients were between 30 and 59 years old. WHO types II and III represented 22% and 78% of the subjects, respectively, and 75.5% of cases were locally advanced (stages III-IVB). Although the age-standardized incidence from the 4 institutions was numerically higher than the published age-standardized incidence (2.07 per 100,000 vs. 1.2 per 100,000), two-proportion z-test showed no significant difference between them (P = 0.68). A more concerted effort is needed for a better approximation of the country's NPC disease burden.