Impact of radiation on tooth loss in patients with head and neck cancer: a retrospective dosimetric-based study.

OBJECTIVE: To characterize the dental adverse events after head and neck radiation therapy (HNRT) and to investigate the impact of regional radiation dose upon tooth loss outcomes. STUDY DESIGN: A retrospective dosimetric-based analysis was conducted to assess dental events affecting post-HNRT extracted teeth and the impact of 3 different radiation doses (<30 Gy, 30-60 Gy, and >60 Gy) upon tooth loss. In addition, post-HNRT extractions outcomes and mean parotid glands dosimetry and salivary changes were analyzed. RESULTS: Sixty-six patients who underwent HNRT were included in the analysis. Radiation caries was the most frequent (67.8%) post-HNRT dental adverse event, and maxillary molars ipsilateral to the tumor were lost earlier compared with the others (P < .001). The odds ratio for post-HNRT tooth extraction risk was approximately 3-fold higher for teeth exposed to >60 Gy (confidence interval, 1.56-5.35; P < .001), followed by an increased risk of delayed healing and osteoradionecrosis (ORN) in sites receiving doses above 50 Gy. CONCLUSIONS: Radiation caries was the major cause of dental extractions after HNRT, and the dosimetric analysis suggested that a high dose of radiation may negatively impact the dentition of survivors of head and neck cancer, increasing the risk of tooth loss and ORN.

Hypofractionated radiotherapy in breast cancer: a 10-year single institution experience.

BACKGROUND: Moderately post-operative hypofractionated radiotherapy (HYPO-RT) for breast cancer is a safe and effective strategy as seen in large prospective trials. This study aimed to assess overall and disease-free survivals, local control, and acute and late toxicities in patients treated with HYPO-RT. MATERIALS AND METHODS: Data from patients submitted to post-operative HYPO-RT, with or without boost, were evaluated retrospectively. Demographic, disease, and treatment characteristics were collected. RESULTS: From March 2009 to December 2016, 393 patients were treated. Breast-conserving surgery was performed in 94.7%, immediate reconstruction after mastectomy in 6 (1.5%). Most patients (91.2%) had initial stage (0 to IIA), and chemotherapy was performed in 42.0%, HYPO-RT was mainly performed in 15 or 16 daily fractions of 267 cGy and 265 cGy, respectively. The median follow-up was 5.7 years. There were 25 deaths (6.4%) and 17 (4.3%) local recurrences. At 5 and 10 years, the overall survival, local control, and disease-free survival were, respectively, 96.0% and 79.3%, 99.2% and 94.9%, 96.6%, and 91.9%. Acute grade 3 or 4 dermatitis was observed in 0.9%. Late grade 1 or 2 occurred in less than 3% of the patients. CONCLUSION: HYPO-RT is a safe and effective radiotherapy regimen with excellent disease control and overall survival rates, with low acute and late toxicity rates.

Prospective validation of a core curriculum progress assimilation instrument for radiation oncology residentship.

OBJECTIVES: To develop a tool that could assess residents' knowledge beyond simple information gathering and evaluate its reliability. METHODS: An assessment tool of 40 objective questions and at least one essay-based question was developed to assess residents' comprehension of general radiation oncology accordingly to validated training curricula beyond level 2 in the Bloom scale. With randomized content, questions were developed such as to be classified as at least 2 in the Bloom scale, so that reasoning and not only information gathering could be assessed. Criteria validation was made using the Classical Test Theory to describe difficulty and discrimination of each item. Reliability was tested by internal consistency using the Cronbach alpha test. RESULTS: Between 2016 and 2019, 24 residents were assessed. Six different versions of the test were made with a total of 240 objective questions and 18 essay-based questions. Five of the six versions were deemed valid and reliable. Comparisons between 1st (PGY-1) and 3rd (PGY-3) year residents were made. Consistently, PGY-3 residents had scores 150% higher than PGY-1 residents. Only two different PGY-3 reached the most complex level of answers in the essay-based questions. The results demonstrated that the major part of the acquired knowledge and retention occurs in the first six months of training rather than in all the following period. CONCLUSION: The instrument can be considered valid. This developed instrument also raised the hypothesis that residents may not assess and analyze their acquired knowledge beyond the application level.