Cardiovascular toxicities of androgen deprivation therapy in Asian men with localized prostate cancer after curative radiotherapy: a registry-based observational study.

BACKGROUND: Androgen deprivation therapy (ADT) and radiotherapy (RT) are the mainstay treatment for localized prostate cancer and recurrence after surgery. Cardiovascular (CV) toxicity of ADT is increasingly recognized, and the risk relates to pre-existing risk factors and ADT modalities. Despite ethnic differences in the prevalence of CV risk factors and variations of CV mortality, data on ADT-related cardiotoxicities in the Asian population remain inconclusive. Our registry-based study investigated ADT-related major adverse cardiovascular events (MACE) after primary or salvage RT. METHODS: Our study combined two prospectively established registry databases from National Cancer Center Singapore and National Heart Center Singapore. The primary endpoint is time to first MACE after treatment. MACE is defined as myocardial infarction, stroke, unstable angina, or cardiovascular death. Two types of propensity score adjustments, including ADT propensity score as a covariate in the multivariable regression model and propensity score weighting, were applied to balance baseline features and CV risk factors between RT alone and RT + ADT groups. RESULTS: From 2000 to 2019, 1940 patients received either RT alone (n = 494) or RT + ADT (n = 1446) were included. After a median follow-up of 10 years (RT) and 7.2 years (RT+ ADT), the cumulative incidence of MACE at 1, 3 and 9 years was 1.2, 5 and 16.2% in RT group, and 1.1, 5.2 and 17.6% in RT + ADT group, respectively. There were no differences in the incidence of MACE between 2 groups (HR 1.01, 95% CI 0.78-1.30, p = 0.969). Pre-treatment CV risk factors were common (80%), and CV disease (15.9%) was the second leading cause of death after prostate cancer (21.1%). On univariate analysis, older age, Indians and Malays, pre-existing CV risk factors, and history of MACE were associated with higher MACE risk. After propensity score adjustments, there remained no significant differences in MACE risk between RT + ADT and RT group on multivariable analysis. CONCLUSIONS: In our registry-based study, ADT is not associated with increased risk of major cardiovascular events among Southeast Asian men with prostate cancer after curative radiotherapy.

Clinical and dosimetric predictors of physician and patient reported xerostomia following intensity modulated radiotherapy for nasopharyngeal cancer - A prospective cohort analysis.

BACKGROUND AND PURPOSE: To compare physician and patient reported xerostomia and correlate xerostomia with dosimetric and clinical parameters for nasopharyngeal cancer (NPC) patients treated with intensity modulated radiotherapy (IMRT) and chemotherapy. PATIENTS AND METHODS: We analyzed the data of 172 patients with locally advanced NPC. Xerostomia was evaluated via physician-rated xerostomia based on RTOG morbidity score (E1), patient-rated dry mouth (E2) and patient-rated sticky saliva (E3) based on EORTC QLQ-HN35 questionnaire. Primary endpoint was the presence of moderate to severe xerostomia at 2-year after completion of IMRT. RESULTS: The levels of physician reported xerostomia (E1) were consistently lower than patient reported dry mouth (E2) over time. The incidence of patients with xerostomia at 3-month post RT was 58% based on E1, 70% based on E2, and 51% based on E3. The corresponding incidence rates at 2-year post RT was 26% (E1), 36% (E2) and 21% (E3). The incidence of patients with xerostomia at 1-year post RT was close to that at 2-year post RT for all the 3 endpoints. The average Dmean of parotid glands was 41.5 Gy (range: 31.0 Gy-65.9 Gy, median: 40.7 Gy). No dosimetric parameters were significantly associated with xerostomia. CONCLUSION: Significant proportion of patients still experienced long term xerostomia with IMRT. Dose-effect relationships between xerostomia and the parotid glands were not observed in this study.

Impact of comorbidity on tolerability and survival following curative intent intensity modulated radiotherapy in older patients with nasopharyngeal cancer.

OBJECTIVE: This study aimed to evaluate the predictive factors for survival and acute toxicities in older patients with NPC treated with curative intent IMRT. MATERIALS AND METHODS: Older patients aged 65 years and above with non-metastatic NPC treated with curative intent IMRT between 2003 and 2013 were retrospectively analysed. Variables examined were gender, age, overall stage, chemotherapy use, Eastern Cooperative Oncology Group (ECOG) performance status and comorbidity. The comorbidity severity was determined by adult comorbidity evaluation (ACE-27). We considered hospitalization or placement of feeding tube during and up to one month post radiotherapy as surrogate endpoint for significant acute toxicities. Other endpoints examined were: OS (overall survival), DFS (disease free survival), DSS (disease specific survival). RESULTS: A total of 185 patients were eligible for analysis. Median age was 70 (65-86 years). Most of the patients presented with Stage III and IVA/B (n = 127, 68.7%), of good performance status of ECOG 0-1 (n = 176, 95.1%) and had low comorbidities with ACE-27 score of 0-1 (n = 141, 76.2%). Chemotherapy was delivered to 84 patients (45.4%). OS, DFS, and DSS were 64.5%, 51.4%, and 72.8% respectively. High comorbidity burden but not chemotherapy had significant impact on OS and DFS in patients with advanced stage. Fifty patients (27%) required tube feeding or hospitalization during the course of RT. Males, chemotherapy use and ECOG score ≥2 were significant predictors of tube feeding or hospitalization during RT. CONCLUSION: Curative IMRT was associated with excellent survival outcomes in older patients with NPC. Comorbidity but not chemotherapy was associated with prognosis in advanced stage. Careful monitoring and intensive support should be instituted in older males with ECOG score ≥2 receiving chemo-radiotherapy.

Comparison between 4-MV and 6-MV radiotherapy in T1N0 glottic cancer.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to report the outcomes of a retrospective consecutive cohort study of patients with T1N0M0 glottic carcinoma treated with 4-MV or 6-MV radiotherapy. STUDY DESIGN: Retrospective case-control study. METHODS: This was a retrospective review of all patients with T1N0M0 glottic carcinoma treated with radiotherapy between January 2000 and December 2012 in the Department of Radiation Oncology at National Cancer Center Singapore. A total of 124 patients were included. Clinical endpoints of interest were: local control (LC), overall survival (OS), and disease-specific survival (DSS). Other prognostic factors for LC were also analyzed: age, gender, smoking status, T substage, dose fraction, field size, anterior commissure involvement, total dose, and overall treatment time. RESULTS: Six-megavolt photon radiotherapy was used in 73 patients and 4-MV photon radiotherapy in 51 patients. Median follow-up was 4.9 years. The 5-year LC and OS were as follows: 4 MV, 91.6% and 83.4%; 6 MV, 88.8% and 82.8%; and the 5-year LC, OS, and DSS for all patients were 90.4%, 83.3%, and 98.3%. There was no significant difference in LR and OS between 4-MV and 6-MV radiotherapy (P = .92, P = .16, respectively). In the univariate analysis of LC, none of the prognostic factors was statistically significant. Twenty patients (23%) developed second primary cancers, the majority in the lungs. CONCLUSIONS: Six-megavolt photon radiotherapy yields comparable results to 4-MV photons. Bolus and computed tomographic simulation are useful to ensure adequate dose coverage of target volume. Follow-up postradiotherapy should incorporate chest imaging, smoking cessation advice, and thyroid function test. LEVEL OF EVIDENCE: 4 Laryngoscope, 127:1061-1067, 2017.