Long-term outcomes following stereotactic body radiotherapy boost for oropharyngeal squamous cell carcinoma

Abstract

Background/purpose: To determine the efficacy and toxicity profile of a stereotactic body radiotherapy (SBRT) boost as a first line treatment in patients with oropharyngeal squamous cell carcinoma (OPSCC). Materials and methods: We performed a retrospective cohort study in 195 consecutive OPSCC patients with T1-small T3 disease, treated at Erasmus MC between 2009 and 2016 with a SBRT (3 Â 5.5 Gy) boost after 46 Gy IMRT. Primary endpoints were disease-specific survival (DSS) and Grade !3 toxicity (Common Terminology Criteria). The Kaplan-Meier method and Cox regression model were applied to determine rates and risk factors. Results: The median follow-up was 4.3 years. Treatment compliance was high (100%). Rates of 5-year DSS and late grade !3 toxicity were 85% and 28%, respectively. Five-year overall survival was 67%. The most frequently observed toxicities were mucosal ulceration or soft tissue necrosis (n ¼ 30, 5 year 18%), dysphagia or weight loss (n ¼ 18, 5 year 12%) and osteoradionecrosis (n ¼ 11, 5 year 9%). Current smoker status (hazard ratio [HR] ¼ 2.9, p ¼ .001) and Charlson Comorbidity Index !2 (HR ¼ 1.9, p ¼ .03) were was associated with increased toxicity risk. Tooth extraction prior to RT was associated with increased osteoradionecrosis risk (HR ¼ 6.4, p ¼ .006). Conclusion: We reported on outcomes in the largest patient series to date treated with a hypofractionated boost for OPSCC. Efficacy was good with survival rates comparable to conventionally fractionated (chemo)radiotherapy. Grade !3 toxicity profiles showed high rates of soft tissue necrosis and osteoradionecrosis. Strategies to mitigate severe toxicity risks are under investigation to improve the tolerability of the SBRT boost.

Dental extraction, intensity-modulated radiotherapy of head and neck cancer, and osteoradionecrosis

“…Dental extractions can enhance ORN and dental extraction prior to IMRT seems to come with a reduced risk compared to dental extraction after IMRT in the present review of the literature. Our observation is in line with the prevailing opinion and current practice, but in contrast to recent reports [9][10][11]. The statistical difference in OR and RR was not large enough to be conclusive.…”

“…After analysis and correspondence with authors, eligibility criteria were applied and 87 articles were excluded: 24 articles included patients without IMRT or IMRT was used in less than 20 patients; in 25 studies, distinguishing between patients treated with IMRT or other techniques was not possible for the entire cohort, only for specific subgroups, and absolute figures regarding ORN cases and extractions for IMRT were impossible; in 36 articles, there were incomplete data on dental extractions and individual ORN; the remaining 2 studies marked “other reasons” only reported on ORN grade ≥ 3 [ 10 ]. After the eligibility assessment, 7 studies that met our eligibility criteria were suitable for inclusion (Table 1 ).…”

“…In earlier studies, tooth extractions after RT have been reported to be associated with a high risk of ORN [8]. However, some authors observed that dental extractions prior to RT do not prevent ORN completely [9][10][11]. Currently, there is no conclusive evidence that dental extractions before irradiation offer a significant risk reduction for the development of ORN compared to dental extractions after RT, and there are no randomized controlled trials [12].…”

Stereotactic radiotherapy as planned boost after definitive radiotherapy for head and neck cancers: Systematic review

“…The countries represented in this study were Korea ( n = 1), Japan ( n = 1), China ( n = 1), Taiwan ( n = 1), India ( n = 1), Mexico ( n = 1), United States ( n = 2), and Netherlands ( n = 1) 18–26 . Overall, studies ranged from the years 2006–2020, with a median follow‐up time range from 8–56 months.…”

High-dose stereotactic radiotherapy boost in the treatment of squamous cell carcinoma of the head and neck region

“…This paper confirms that a combination of SBRT and IMRT can lead to successful outcomes, but side effects were the most serious problem of this treatment. Most soft tissue necrosis appears during the 12 months after the completion of RTH [ 11 ]. In the same follow-up period, we did not detect any serious side effects associated with the SBRT boost.…”