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PURPOSE: Patients with p16 positive tonsillar cancer (p16 + TC) have an excellent prognosis and long-life expectancy. Deintensification of therapy is a prevalent topic of discussion. Proton radiotherapy is one way to reduce radiation exposure and thus reduce acute and late toxicity. The aim is to evaluate treatment outcomes and toxicity of postoperative treatment with intensity-modulated proton therapy (IMPT). METHODS: Between September 2013 and November 2021, 47 patients with p16 + TC were treated postoperatively with IMPT. Median age was 54.9 (38.2-74.9) years, 31 were males and 16 were females. All patients had squamous cell carcinoma and underwent surgery as a primary treatment. Median dose of radiotherapy was 66 GyE in 33 fractions. Bilateral neck irradiation was used in 39 patients and unilateral in 8. Concomitant chemotherapy was applied in 24 patients. RESULTS: Median follow-up time was 4.2 (0.15-9.64) years. Five-year overall survival, relapse free survival and local control were 95.7%, 97.8% and 100%. The most common acute toxicities were dermatitis and mucositis, with grade 2 + in 61.7% and 70.2% of patients. No acute percutaneous gastrostomy insertion was necessary and intravenous rehydration was used in 12.8% of patients. The most common late toxicity was grade 1 xerostomia in 70.2% of patients and grade 2 in 10.6% of patients. Subcutaneous fibrosis of grades 2 and 3 occurred in 17.0% and 2.1% of patients, respectively. One patient developed late severe dysphagia and became PEG-dependent. CONCLUSION: IMPT for the postoperative treatment of p16 + TC is feasible with excellent efficiency and acceptable acute and late toxicity.
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BACKGROUND: We retrospectively analyzed the 5-year biochemical disease-free survival (bDFS) and occurrence of late toxicity in prostate cancer patients treated with pencil beam scanning (PBS) proton radiotherapy. METHODOLOGY: In the period from January 2013 to June 2018, 853 patients with prostate cancer were treated with an ultra-hypofractionated schedule (36.25 GyE/five fractions). The mean PSA value was 6.7 (0.7-19.7) µg/L. There were 318 (37.3%), 314 (36.8%), and 221 (25.9%) patients at low (LR), favorable intermediate (F-IR), and unfavorable intermediate risk (U-IR), respectively. Neoadjuvant hormonal therapy was administered to 197 (23.1%) patients, and 7 (0.8%) patients had adjuvant hormonal therapy. The whole group of patients reached median follow-up time at 62.7 months, and their mean age was 64.8 (40.0-85.7) years. The bDFS rates and late toxicity profile were evaluated. RESULTS: Median treatment time was 10 (7-38) days. Estimated 5-year bDFS rates were 96.5%, 93.7%, and 91.2% for low-, favorable intermediate-, and unfavorable intermediate-risk groups, respectively. Cumulative late toxicity (CTCAE v4.0) of G2+ was as follows: gastrointestinal (GI)-G2: 9.1%; G3: 0.5%; genitourinary (GU)-G2: 4.3%, and no G3 toxicity was observed. PSA relapse was observed in 58 (6.8%) patients: 16 local, 22 lymph node, 4 bone recurrences, and 10 combined sites of relapse were detected. Throughout the follow-up period, 40 patients (4.7%) died, though none due to prostate cancer. CONCLUSION: Ultra-hypofractionated proton beam radiotherapy is an effective treatment for low- and favorable intermediate-risk prostate cancer, with long-term bDFS rates comparable to other techniques. It is promising for unfavorable intermediate-risk prostate cancer and has acceptable long-term GI and favorable GU toxicity.