Regorafenib has been demonstrated to prolong survival in patients with metastatic colorectal cancer refractory to standard chemotherapy. However, overall survival is limited to 2.5 months. The present report describes a unique case of metastatic colon cancer, which showed a complete response to regorafenib. A 54-year-old woman was diagnosed with right colon cancer obstruction with peritoneal seeding. The patient underwent laparoscopic right hemicolectomy, and the pathology was T4aN2bM1, moderately differentiated adenocarcinoma with high microsatellite instability (MSI-H) and wild-type KRAS/NRAS. The first-line chemotherapy was fluorouracil, leucovorin and irinotecan with cetuximab. After 12 cycles, recurrence at the anastomotic site was identified. The patient underwent palliative colectomy, and superior mesenteric artery (SMA) lymph node metastases were evident. The patient received second-line chemotherapy of fluorouracil, leucovorin and oxaliplatin with bevacizumab. Progression of metastasis to the right common iliac lymph nodes was detected after only four cycles of therapy. Thereafter, the patient received regorafenib as third-line therapy, starting with 160 mg for two cycles and reducing the dose thereafter, for a total of 17 cycles. The previously confirmed SMA lymph node metastasis had disappeared after the seventh cycle, and the right common iliac lymph node metastasis was not visible on CT after the 16th cycle. The patient decided to terminate regorafenib and has not experienced recurrence 2 years since treatment cessation. This is the first report of refractory metastatic colon cancer with MSI-H showing a complete response to regorafenib. Further studies are required to investigate the efficacy of regorafenib in refractory metastatic colon cancer with MSI-H and to elucidate the mechanism of remission.

BackgroundThere is no consensus as to how much ileal resection is sufficient when performing a right hemicolectomy for right colon cancers. Locally advanced caecal cancer has the highest incidence of peri‐ileal lymph node metastasis. Therefore, this study investigated whether the 10 cm ileum resection suggested by the Japanese Society for Cancer of the Colon and Rectum is oncologically safe in stage II and III caecal cancer.MethodsThe prospectively collected medical records of stage II and III caecal cancer patients who underwent a right hemicolectomy with at least D2 lymph node dissection were reviewed retrospectively. The patients were divided into two groups according to the length of proximal ileal resected: group 1 (≤10 cm) and group 2 (>10 cm). Factors contributing to the 5‐year overall survival (OS) were analysed.ResultsThe study enrolled 89 patients with pathological stage II or III caecal cancer. The >10 cm group tended to be younger (P = 0.0938) with higher pathological N stages (P = 0.0899) than the ≤10 cm group. The 5‐year OS did not differ between the two groups. No significant difference was found between the two groups according to stage. Age (HR = 1.06, 95% CI = 1.02–1.10, P = 0.0069) and N2 stage (HR = 5.38, 95% CI = 1.90–15.28, P = 0.0016) were significantly associated with OS in both uni‐ and multivariate analyses.ConclusionsThere was no OS benefit to resecting >10 cm of ileum in either stage II or III caecal cancer patients. Hence, we suggest that the ‘10 cm rule’ is sufficient for stage II and III caecal cancer patients.

Purpose: Peritoneal carcinomatosis (PC) has been considered a terminal condition and cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIEPC) is regarded as an alternative therapeutic option. This study aimed to evaluate the 30-day clinical outcomes of CRS/HIPEC and the feasibility of the surgery by investigating the morbidity and mortality in Inje University Hospital. Methods: Data were retrospectively collected from 19 patients with PC who underwent CRS/HIPEC at Inje University Hospital in 2018. We evaluated pre-, intra-operative parameters and postoperative clinical outcomes and early complications. Results: The mean operating time was 506.95 minutes and the mean blood loss was 837.11 mL. Six cases (31.58%) had morbidity of grade III or above. A longer operating time (≥ 560 minutes, P=0.038) and large blood loss (≥ 700 mL, P=0.060) were positively correlated with grade III or worse postoperative complications. Conclusion: Our early experience with CRS/HIPEC resulted in a 31.58% morbidity rate of grade III and above, with risk factors being longer operating time and greater intraoperative blood loss. As the surgical team's skills improve, a shorter operating time with less intraoperative blood loss could result in better short-term outcomes of CRS/HIPEC.