DISCUSSION
toxicity, SIB, anal canal cancer, human papilloma virus
RECURRENCE, ADVERSE EVENTS, DISEASE, HUMAN PAPILLOMA VIRUS, TUMOR PROGRESSION
In the current study, all the patients received two cycles of 5-FU, and MMC and completed the planned radiotherapy dose. The 2-year DFS was 77.4% (95% CI, 58.4–88.5%), which was similar to that reported in previous studies evaluating the efficacy of chemoradiotherapy with 5-FU and MMC for patients with SCCAC (List of characteristics in previous and current studiesAbbreviations: OS, overall survival; DFS, disease free survival; LC, locoregional control; CFS, colostomy-free survival; RT, radiotherapy; CRT, chemoradiotherapy; 5-FU, 5-fluorouracil; MMC, mitomycin-C; yr, year
In the current study, local recurrence at the time of analysis was observed in five patients, and four of the five patients who could not achieve CR experienced residual primary tumor progression. The 2-year LC rate was 83.9%. These results were similar to those of previous studies [Acute hematologic toxicity caused by chemoradiotherapy with 5-FU and MMC was significantly higher than that caused by 5-FU and CDDP in the RTOG 98–11 trial (61% vs 42%, The optimal dose of chemoradiotherapy for SCCAC remains controversial. In the UKCCCR and ACCORD03 trials, a total dose of ≥60 Gy was administered with center split [In Japan, a reduced dose of 5-FU (700–800 mg/mThe number of patients statistically required for this study was 36; however, only 31 patients were enrolled as the supply of MMC was suspended from October 2019 onward. Therefore, we could not conclude whether the results of this study were positive or negative. Furthermore, various radiotherapy techniques such as 3DCRT, IMRT with the two-step technique, and IMRT with SIB were included, and biomarkers such as human papilloma virus and p16 were not routinely screened. Further studies are needed to establish the optimal dose of radiotherapy according to risk factors, such as T/N stage and biomarker levels and an optimal radiotherapy technique, including dose constraints for organs at risk.The required number of eligible patients was not reached in the current study. However, this multicenter phase II study showed excellent compliance and demonstrated that chemoradiotherapy with 59.4 Gy plus a reduced dose of 5-FU (800 mg/mIn conclusion, good DFS with a low rate of late adverse events was observed. Chemoradiotherapy with 5-FU and MMC and administration of a total dose of 59.4 Gy for patients with anal canal cancer was an effective definitive treatment.