RAS mutant transverse colon cancer with multiple liver metastases achieving long-term disease-free survival with postoperative maintenance therapy with aflibercept + FOLFIRI and four repeated radical resections: a case report.

Background: Management of patients with colorectal liver metastases (CRLMs) requires a multidisciplinary approach. For patients with progression of RAS mutant tumors, the choice of angiogenesis inhibitors can be controversial. Here, we report a patient with RAS mutant CRLMs achieving long-term disease-free survival with repeated R0 resections and perioperative treatment, especially aflibercept + FOLFIRI (5-fluorouracil, levofolinate, irinotecan), which may have prevented long-term recurrence.

Case presentation: The patient was a 37 year-old woman diagnosed with RAS mutant transverse colon cancer with 19 LMs. As the metastases were limited to the liver, we introduced systemic chemotherapy aiming at conversion surgery. After six cycles of bevacizumab + FOLFOXIRI (5-fluorouracil, levofolinate, oxaliplatin, irinotecan), we performed partial hepatectomy for all LMs, and left hemicolectomy for the primary tumor after another four cycles of bevacizumab + FOLFIRI. Three months after surgery, the patient presented with massive ovarian metastases with carcinomatous ascites. We conducted bilateral oophorectomy, and initiated aflibercept + FOLFIRI therapy considering the possibility of resistance to bevacizumab. The patient was recurrence-free for 2 years during aflibercept + FOLFIRI treatment. After its discontinuation, two distant metastases developed. Both were resectable and the patient achieved recurrence-free survival of 2 years and 3 months after the last operation (6 years since initiation of treatment), without additional chemotherapy.

Conclusions: We believe that multidisciplinary treatment aimed at complete resection could lead to long-term survival even in patients with repeated recurrence of CRLMs. Aflibercept + FOLFIRI could be effective in controlling metastasis of RAS mutant colon cancer even after treatment with bevacizumab.