Standardization of surgical treatment for advanced lower rectal cancer and efforts for future individualization

[Introduction] The principle of locally advanced rectal cancer is total mesorectal excision (TME) and bilateral lateral dissection (LLND). In western contries, preoperative chemoradiationtherapy (CRT) followed by TME alone is performed. Although preoperative CRT is thought to be good in local control, the survival rate is not improved. [Subjects / Methods] Expecting survival rate implovement, we perform neoadjuvant chemotherapy (NAC) for locally advanced rectal cancer. NAC with Doublet or Triplet regimens was performed. Subjects were 67 cases from 2011 to 2020. The male-female ratio was 46:21 and the age was 19-76 (median 64). [Results] The selection ratio of Doublet / Triplet was 45:22 and the completion rate of NAC was 61/67 (91.0%). Grade 1b or better was observed in 32 cases. Although recurrence was observed in 14 cases, cancer deaths have remained in 2 cases. There was no difference between Doublet / Triplet in histological effect and recurrence / survival time. [Conclusion] These results suggest that preoperative and postoperative adjuvant chemotherapy for locally advanced rectal cancer can be safely performed. Presently, we are conducting comprehensive analyses of genes in biopsy specimens before and after NAC treatment using next generation sequencing to define the biomarkers of patient factors for therapeutic effects and to measure stratification of patients to perform NAC.