Intensified irinotecan-based neoadjuvant chemoradiotherapy in rectal cancer: Four consecutive designed studies to minimize acute toxicity and to optimize efficacy measured by pathologic complete response

Background. The objective of the present study was to analyse toxicity and efficacy of irinotecan-based neoadjuvant chemoradiotherapy by the help of four consecutively planed and prospectively performed phase II studies. Patients and methods. Patients with locally advanced rectal cancer received radiotherapy and concurrently chemotherapy consisting 5-Fu/capecitabine in a continuous or intermittent application and irinotecan in two different total doses (240 vs. 200 mg/m2). Results. Diarrhea CTC grade III was seen in 35% in continuous application of 5-Fu/capecitabine versus 12.5% in intermittent application (p =  0,008). Complete response according to the irinotecan dose during chemoradiotherapy (240 mg/m2 vs. 200 mg/m2) was 24% and 0%. Conclusions. Chemoradiotherapy of the last phase II study with intermittent capecitabine (1500 mg/m2/day, delivered on days 1–14 and 22–35) and irinotecan (4 × 60 mg/m2) concurrently to radiotherapy is a safe treatment with low toxicity and high efficacy.