Short-term outcomes of preoperative chemoradiotherapy with S-1 for locally advanced rectal cancer

The purpose of the present study was to evaluate the short-term results of preoperative chemoradiation therapy with S-1 for locally advanced rectal cancer. A total of 32 patients with advanced rectal cancer who had been treated with preoperative chemoradiotherapy with S-1 and underwent surgical resection between May 2012 and December 2019 were analyzed. Advanced rectal cancer of clinical stage II and III was diagnosed in 13 (41%) and 19 (59%) patients, respectively. Therapeutic toxicities of anemia (24 patients; 75%), anal pain (22 patients; 69%) and skin and subcutaneous tissue disorders (19 patients; 59%) were frequently observed in all grades. Grade ≥3 leukopenia, anemia, neutrophil count reduction, platelet count reduction and diarrhea were identified in 2 (6%), 1 (3%), 1 (3%), 1 (3%) and 1 (3%) patients, respectively. A total of 29 patients (91%) completed this therapy without any change to the protocol or dosage. R0 resection was performed in 100% of the patients, and no postoperative mortality was observed. Pathological complete response was observed in 9 cases (28.1%). This therapy can be considered for cases of locally advanced rectal cancer due to its acceptable toxicity and relatively high antitumor effect.