ABSTRACT
Background: Radiation-induced hypothyroidism (RIH) is common after neck irradiation, and biochemical evaluation of thyroid function is recommended periodically for early diagnosis and treatment. This study aimed to evaluate the predictors of RIH after completion of adjuvant radiotherapy (RT) for primary oral squamous cell carcinoma (OSCC). Methods: This is a retrospective study involving 195 patients who received RT after surgery for OSCC between August 2011 and December 2016. Thyroid function tests were obtained every 6 months and patients were considered to be hypothyroid if thyroid-stimulating hormone level was >5 mIU/mL. Results: The study cohort comprised 130 men with a median age of 52 years (range 21–77 years). About 107 (54.87%) patients developed hypothyroidism, with a median of 21 months (range 2–67 months) for the development of RIH. Women [41 (63.1%) versus 66 (50.8%), p=0.035], addition of chemotherapy [36 (63.2%) versus 71 (51.4%), p= 0.019], and higher cumulative dose to the thyroid gland (median dose 4690 cGy versus 2981 cGy, P < 0.001) resulted in higher incidence of RIH on univariate analysis. On multivariate Cox regression analysis, female sex (P = 0.042), bilateral irradiation (P = 0.046), and cumulative dose to the thyroid (P = 0.001) were factors associated with increased risk of developing RIH. Conclusion: The addition of chemotherapy, high dose of radiation to the thyroid gland, bilateral irradiation, and female sex were at higher risk of developing RIH. However, more studies are required to identify the dose-volume constraints of the thyroid gland
ABSTRACT
Context: Stereotactic body radiotherapy (SBRT) is increasingly being used for early-stage lung cancer and lung oligometastases. Aims: To report our experience of setting up lung SBRT and early clinical outcomes. Settings and Design: This was a retrospective, interventional, cohort study. Subjects and Methods: Patients were identified from multidisciplinary tumor board meetings. They underwent four-dimensional computed tomography-based planning. The ROSEL trial protocol, the Radiation Therapy Oncology Group (RTOG) 0236, and the UK-Stereotactic Ablative Body Radiotherapy Consortium guidelines were used for target volume and organs-at-risks (OARs) delineation, dosimetry, and plan quality assessment. Each SBRT plan underwent patient-specific quality assurance (QA). Daily online image guidance using KVCT or MVCT was done to ensure accurate treatment delivery. Statistical Analysis Used: Microsoft Excel 2010 was used for data analysis. Results: Fifteen patients were treated to one or more lung tumors. One patient received helical tomotherapy in view of bilateral lung oligometastases at similar axial levels. All the remaining patients received volumetric modulated arc therapy (VMAT)-based treatment. The prescription dose varied from 40 to 60 Gy in 5–8 fractions with alternate-day treatment. The mean and median lung V20 was 5.24% and 5.16%, respectively (range, 1.66%–9.10%). The mean and median conformity indexes were 1.02 and 1.06, respectively (range, 0.70–1.18). After a median follow-up of 17 months, the locoregional control rate was 93.3%. Conclusions: SBRT was implemented using careful evaluation of OAR dose constraints, dosimetric accuracy and plan quality, patient-specific QA, and online image guidance for accurate treatment delivery. It was safe and effective for early-stage nonsmall cell lung cancer and lung metastases. Prospective data were collected to audit our outcomes
ABSTRACT
INTRODUCTION: Radical radiotherapy (RT) with curative intent, with or without chemotherapy, is the standard treatment for inoperable, locally advanced nonsmall cell lung cancer (NSCLC). MATERIALS AND METHODS: We retrospectively reviewed the data for all 288 patients who presented with inoperable, locally advanced NSCLC at our institution, between May 2011 and December 2016. RESULTS: RT alone or sequential chemoradiotherapy (SCRT) or concurrent chemoradiotherapy (CCRT) was used for 213 patients. Median age was 64 years (range: 27–88 years). Stage-III was the biggest stage group with 189 (88.7%) patients. Most patients with performance status (PS) 0 or 1 received CCRT, whereas most patients with PS 2 received RT alone (P < 0.001). CCRT, SCRT, and RT alone were used for 120 (56.3%), 24 (11.3%), and 69 (32.4%) patients, respectively. A third of all patients (32.4%) required either volumetric-modulated arc radiotherapy (VMAT) or tomotherapy. Median follow-up was 16 months. The median progression-free survival and median overall survival (OS) were 11 and 20 months, respectively. One-year OS and 2-year OS were 67.9% and 40.7%, respectively. Patients treated using CCRT lived significantly longer with a median survival of 28 months, compared with 13 months using SCRT and RT alone (P < 0.001). On multivariate analysis, OS was significantly affected by age, stage group, treatment approach, and response to treatment. CONCLUSION: RT including CCRT is feasible, safe, and well tolerated in our patient population and results in survival benefits comparable with published literature. CCRT should be considered for all patients with inoperable, locally advanced NSCLC, who are fit and have good PS.