Durable responses to TAS-102 plus bevacizumab and TACE in salvage-line treatment of KRAS-mutated and MSS metastatic colorectal cancer: a case report.

Patients with KRAS-mutated and microsatellite-stable (MSS) metastatic colorectal cancer (mCRC) often have limited options in salvage-line treatment. Reasonable combination strategy may be a valuable exploration. Here, we report a patient with KRAS-mutated and MSS metastatic rectal adenocarcinoma at stage IVB. After failure of previous standard treatment, a durable stable disease was achieved under the fifth-line treatment of TAS-102 plus bevacizumab and transcatheter arterial chemoembolization (TACE). To date, the patient had a PFS of more than 11.6 months with significantly declined tumor markers, alleviated clinical symptoms and improved quality of life. This case suggests that TAS-102 combined with re-challenged bevacizumab and well-timed TACE intervention is an effective strategy for KRAS-mutated and MSS mCRC, with good tolerance and manageable safety, even following disease progression on prior fruquintinib and regorafenib therapies.