Abstract
Evaluation of the circumferential resection margin (CRM) of locally advanced rectal cancer is an important prognostic factor for predicting local recurrence rate and distant metastasis and is currently the standard practice mainly in Western countries. In Japan, however, CRM assessment is not commonly performed and thus has not been sufficiently studied. Therefore, we aimed to evaluate CRM using a histopathological specimen processing method developed independently by our department. Ten patients with locally advanced rectal cancer who underwent surgery between January 2022 and March 2024 were included in the study. Although preoperative treatment was given to all the 10 patients, CRM was measurable in all cases using this method. As a result, one patient was found to be CRM-positive. The average number of lymph nodes dissected was 14, and the average distal margin (DM) was 20 mm, which was comparable to those of the current pathological specimen processing method. It is imperative to establish the global standard CRM assessment method in Japan. This also should be done in a way that aligns with the current guidelines for specimen processing methods outlined in the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (JCCRC). Our method was able to minimize the burden on pathologists and lower gastrointestinal surgeons as much as possible while enabling more accurate CRM measurement. In the future, it will be necessary to accumulate more cases, identify potential problems, and prospectively evaluate the effectiveness of this method in a multicenter collaborative study.
