Purpose: Helical tomotherapy (HT) has been recently introduced in the neoadjuvant treatment of locally advanced rectal cancer. Aim of this study is to report the toxicity and local control rates of a large series of locally advanced rectal cancer patients treated with neoadjuvant chemotherapy and HT under daily image guidance followed by surgery.
Methods: Data from 117 locally advanced rectal cancer patients treated at two Swiss Radiotherapy departments were collected and analyzed. Radiotherapy consisted of 45 Gy (1.8 Gy/fraction, 5 fractions/week delivered in 5 weeks) to the regional pelvic lymph nodes. Seventy patients also received a simultaneous integrated boost (SIB) up to 50 Gy to the tumor and involved nodes (2 Gy/fraction, 5 fractions/week delivered in 5 weeks). Chemotherapy consisted of capecitabine 825 mg/m2, twice daily, during the irradiation days. After a median interval of 59 days [95% confidence interval (CI) 53-65 days), all patients underwent surgery.
Results: Median follow-up was 45 months (range 4-90 months). The overall rate of acute grade 2-4 toxicity was 18.8% (n = 22). Four patients (3.4%) presented a grade 3 dermatitis (n = 1) or diarrhea (n = 3), and 1 (0.8%) demonstrated grade 4 rectal toxicity. No patients presented with grade ≥ 3 hematologic toxicity. Six patients (5.1%) had late grade 3 gastrointestinal toxicity. The 4-year local control rate was 88.4% (95% CI 87.5-88.5%).
Conclusions: Neoadjuvant chemoradiotherapy delivered with HT under daily image guidance is well tolerated and shows a high 4-year local control rates.
Keywords: Helical tomotherapy; Image-guided radiotherapy; Neoadjuvant chemoradiotherapy; Rectal cancer; Toxicity.