[Laparoscopic Abdominoperineal Resection after Preoperative Chemoradiotherapy for Adenocarcinoma Associated with Anal Fistula]

A 72-year-old man had a chief complaint of anal pain and difficulty in defecation. He was diagnosed with adenocarcinoma by biopsy from a tumor of the anal canal. A computed tomography scan revealed neither regional lymph node metastasis nor distant metastasis. Hence, he was diagnosed with cT3N0M0, cStage Ⅱa anal canal cancer. Preoperative capecitabine- based chemoradiotherapy(CRT)(50.4 Gy in 28 fractions of 1.8 Gy each)was implemented. Digital rectal examination and imaging evaluation 8 weeks after preoperative CRT revealed that the tumor had shrunk. Fifteen weeks after preoperative CRT, laparoscopic abdominoperineal resection was performed. The pathological findings showed mucinous adenocarcinoma associated with anal fistula. At present, 12 months after the operation, no local recurrence and distant metastasis has been detected under follow-up evaluations.

[A Case of High-Frequency Microsatellite Instability in Colorectal Cancer with MSH2 Mutation Detected Using Gene Panel Testing with a Next-Generation Sequencer]

Here, we report about a woman in her 30s who had peritoneal dissemination and multiple colon cancer with high-frequency microsatellite instability(MSI-H). Her father, paternal grandfather, and maternal grandmother had a history of colorectal cancer treatment. Thus, Lynch syndrome was suspected. We performed R0 resection for peritoneal dissemination and subsequent peritoneal dissemination. A 435-gene panel testing using a next-generation sequencer identified MSH2 and other mutations in the tumor. Hence, we speculated that she could have a germline mutation of MSH2, which causes Lynch syndrome. In the future, if she wishes to receive genetic counseling and undergo germline testing for variants to confirm the diagnosis of Lynch syndrome, we will perform them after receiving informed consent.

Verification of the Japanese staging system for rectal cancer, focusing on differences with the TNM classification

PURPOSE

The 9th Japanese Classification of Colorectal Cancer (9th JSCCR) has two main differences from the TNM classification (8th AJCC): first, main or lateral lymph node metastasis is classified as jN3; second, tumor nodules (ND) are treated as lymph node metastasis. In this study, we verified the 9th JSCCR for rectal cancer, focusing on the differences with the 8th AJCC.

METHODS

This retrospective analysis involved 212 patients with stage I-III rectal cancer. ND was evaluated using whole-mount sections. We evaluated the relapse-free survival of each staging system, and compared the prognostic significance of the different staging systems using the Akaike information criterion (AIC) and Harrell's concordance index (c-index).

RESULTS

Main or lateral lymph node metastasis was detected in nine of 212 (4%) patients. ND was detected in 79 of 212 (37%) patients. The best risk stratification power was observed in the 9th JSCCR (AIC, 759; c-index, 0.708) compared with the 7th JSCCR (AIC, 771; c-index, 0.681), 8th JSCCR (AIC, 768; c-index, 0.696), and the 8th AJCC (AIC, 766; c-index, 0.691).

CONCLUSIONS

The 9th JSCCR, which includes the concepts of jN3 and ND, is useful for the risk stratification of rectal cancer, and the contributes to precise decision-making for follow-up management and adjuvant therapy.

[A Case of Long-Term Survival after Resection for Metachronous Liver and Lung Metastases of Rectal Cancer Associated with Familial Adenomatous Polyposis]

A 37-year-old man was admitted to our hospital for the treatment of familial adenomatous polyposis and rectal carcinoma. He underwent total colectomy with ileoanal anastomosis(pT3N1M0, pStage Ⅲa)followed by adjuvant therapy with S-1. Three months after primary surgery, CT and MRIrevealed liver metastases(S5, S6). Laparoscopic partial hepatectomy was performed. Two years after primary surgery, new liver metastases(S2, S8)were found and we performed open partial hepatectomy and administered mFOLFOX6. Three years and 5 months after primary surgery, right lung metastases(S6, S9) were detected and the patient underwent a thoracoscopic-assisted right lung wedge resection. Repeated resection of metastases might have contributed to the long-survival in our case.