Using a combination of fruquintinib, raltitrexed, and S-1 as a third-line treatment for metastatic colorectal cancer with co-existence of Hodgkin lymphoma: a case report.

Background: Patients with metastatic colorectal cancer (mCRC) beyond second line treatment have a poor prognosis. Fruquintinib, regorafenib, trifluridine/tipiracil (TAS-102), panitumumab and cetuximab combined with single-agent chemotherapy regimens are currently recommended as third-line therapies for patients exhibiting disease progression. Effective late-line therapies for mCRC are urgently needed. The FRESCO randomized clinical trial (RCT) prompts fruquintinib as a third-line treatment in advanced colorectal cancer (CRC). A phase II study in our center reported the efficacy and safety of S-1 plus raltitrexed for the treatment of chemo-refractory mCRC. The combination of the fruquintinib, raltitrexed, and S-1 has not been reported in mCRC. Case Description: This case report presents a patient with mCRC who received third-line treatment with fruquintinib, raltitrexed, and S-1. A 54-year-old male presenting with hematochezia was admitted to West China Hospital of Sichuan University in June 2017 and underwent surgery for a tumor between the rectum and sigmoid colon. Postoperative pathology identified adenocarcinoma (wild-type RAS/RAF, no PIK3CA mutation), and the patient was diagnosed with mCRC (pathological stage, pT3pN1apM0). The mFOLFOX6 regimen was administered. The patient was subsequently diagnosed with Hodgkin lymphoma in May 2018 and treated with the ABVD regimen after multidisciplinary discussions. Liver metastases (intestinal-type adenocarcinoma) were detected in November 2018, and second-line therapy with the FOLFIRI regimen was initiated in January 2019. Lung metastases were identified in September 2019, so the patient was treated with a combination of raltitrexed, S-1, and fruquintinib. A partial response (PR) was detected in November 2019, and the patient underwent resection of the hepatic lesion on November 5, 2020. Computed tomography (CT) images in November 2021 revealed a stable disease; thus, raltitrexed was discontinued, and S-1 and fruquintinib were maintained. The treatment is still responding until the last follow-up (December 2022). Conclusions: The case was characterized by the simultaneous existence of mCRC and Hodgkin lymphoma, which required management by a multidisciplinary team. Third-line therapy with fruquintinib, raltitrexed, and S-1 achieved a PR that permitted surgical resection and enabled a relatively long progression-free survival. The findings suggest that the three agents regimen might be clinically effective as late-line therapy for mCRC.