RT Journal Article SR Electronic T1 Phase II Study of Preoperative Chemoradiotherapy With S-1 Plus Oxaliplatin for Locally Advanced Rectal Cancer (PerSeUS-RC01) JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 6247 OP 6257 DO 10.21873/anticanres.15445 VO 41 IS 12 A1 NOBUHISA MATSUHASHI A1 TAKAO TAKAHASHI A1 CHIHIRO TANAKA A1 KAZUNORI YAWATA A1 MAKOTO YAMADA A1 YOSHINORI IWATA A1 SHIGERU KIYAMA A1 CHIKA MIZUTANI A1 JESSE YU TAJIMA A1 TAKUMA ISHIHARA A1 KAZUHIRO YOSHIDA YR 2021 UL http://ar.iiarjournals.org/content/41/12/6247.abstract AB Background/Aim: We report the end results of a study evaluating the safety and efficacy of preoperative chemoradiotherapy with S-1 plus oxaliplatin. Patients and Methods: Eligible patients had histopathologically confirmed locally advanced rectal carcinoma (LARC; cT3-T4, any N). They received oral S-1 (80 mg/m2/day on days 1-5, 8-12, 22-26, and 29-33) and oxaliplatin by infusion (50 mg/m2/day on days 1, 8, 22, and 29) along with radiotherapy (1.8 Gy/day, total dose: 45 Gy/25 fractions). A chemotherapy gap was included in the third week of radiotherapy. The study endpoint was pathological response rate (Grade 2, 3). Secondary endpoints included rates of pathologic complete response (pCR), R0 resection, disease-free survival (DFS), overall survival (OS), local and distant recurrence, and safety and relative dose intensity. Results: The study enrolled 23 patients at three Centres in Gifu, Japan. All patients received chemoradiotherapy, and 22 underwent surgery. Rates of pathological response, R0 resection, and pathological down-staging were 56.5% (13/23), 95.7% (22/23), and 63.6% (14/22), respectively. There were no grade 4 adverse events, but grade 3 events occurred in 21.7% of patients. The cumulative 3-year local recurrence rate was 8.7%. Distant metastasis occurred in 10 (43.5%) patients, 2 (8.7%) from local recurrence and 2 from secondary pancreatic cancer and lung cancer. There were 8 patients with lung metastasis, 2 with liver metastasis, one with ovarian metastasis, and one with bone metastasis. Three-year rates of DFS and OS were 51.1% (median follow-up 34.3 months) and 91.1% (45.2 months), respectively. Conclusion: The study showed high pathological response rate without severe toxicity and good follow-up results. Unexpectedly, however, this regimen could not control local recurrence and distant metastasis. Nevertheless, adding oxaliplatin to preoperative chemoradiotherapy with S-1 in patients with LARC appears feasible and may safely result in better local control than standard treatment. The study suggests adding treatment with induction chemotherapy in consideration of CEA level and N factor.