Complete response of MSI‑high metastatic colon cancer following treatment with regorafenib: A case report

Abstract

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.

Radiological complete response with regorafenib for multiple lung metastases of ascending colon cancer: a case report

“…To the best of our knowledge, this is the second case in which radiological CR has been identified in a patient with metastatic CRC who was treated with regorafenib. Few publications have described the detailed clinical course of patients with metastatic CRC that is respondent to regorafenib [ 7 , 11 – 13 ], although some reports have addressed prognostic factors related to outcomes with regorafenib. In the REBACCA trial, survival was independently and unfavorably affected by the following variables: poor performance status, short time from initial diagnosis of metastases to the start of regorafenib, low initial regorafenib dose, > 3 metastatic sites, presence of liver metastases, and KRAS mutations.…”

“…It was highly difficult to determine when to discontinue chemotherapy. The first case of metastatic CRC that showed a CR to regorafenib was considered a CR based on CT, PET-CT, and a tumor marker [ 7 ]. If a lack of recurrence had been indicated by PET-CT in our case, it would have been more suggestive of a CR, and a CR may have been determined earlier.…”

“…The CORRECT and CONCUR trials indicated that regorafenib facilitates overall survival and progression-free survival (PFS) when compared to a placebo in metastatic CRC patients; however, disease control (partial response [PR] plus stable disease) was achieved in 51% of the patients, 4% showed a PR, and none showed a complete response (CR) [ 4 , 6 ]. Hyungjoo et al recently reported the first case of metastatic CRC that showed a CR to regorafenib [ 7 ], representing is the only report showing a CR in a metastatic CRC patient. In this report, we present a case of radiological CR with regorafenib for multiple lung metastases of ascending colon cancer.…”

Colorectal medullary carcinoma: heterogeneous presentations of a rare clinico-pathological entity. Report of two cases

“…16 Reports of complete response of MSI-H metastatic CRC following treatment with regorafenib have been published but the effects on CMC are unknown. 17 Although these tumors tend to be right-sided and therefore at first diagnosis they present at an advanced stage, distant metastases are rare and primary spread is to the liver or to the regional lymph nodes. The circumscribed local invasion may stand behind the positive prognosis.…”

“…16 Reports of complete response of MSI-H metastatic CRC following treatment with regorafenib have been published but the effects on CMC are unknown. 17…”