Clinical features, treatment and outcomes of colorectal mucosa-associated lymphoid tissue (MALT) lymphoma: literature reviews published in English between 1993 and 2017

BACKGROUND: Colorectal mucosa-associated lymphoid tissue (MALT) lymphoma (cMALToma) is rare and comprises only 2.5% of the MALT lymphomas. Its etiology and treatment have not been well established. The aim of this systematic literature review was to try to characterize cMALToma and analyze the risk factors for treatment failure with various therapeutic strategies. METHODS: We retrospectively reviewed 50 case reports from 1993 to 2017 through a PubMed search of English medical literature, describing cMALToma. We included 67 patients from previous case reports and we added 6 patients treated for cMALToma in our multicenter institutes. Risk factor analysis was done for treatment failure, defined as remission failure and recurrence. RESULTS: Of 73 patients diagnosed with cMALToma, tumors were located in 54 patients (74.0%) in the rectum, in 10 patients (13.6%) in the right colon, in 3 patients (4.1%) in the transverse colon, and in 6 patients (8.2%) in the sigmoid colon. In first-line treatment, patients achieved complete remission (CR) with surgery (18/19 cases), local resection (18/19 cases), chemotherapy (12/13 cases), radiation therapy (4/5 cases), antibiotics therapy including Helicobacter pylori eradication (12/15 cases), and no treatment (1/2 cases). Among these, eight cases (10.9%) needed second-line treatment, and there was overall remission failure in 3 cases (4.1%). Of the remaining 70 patients with CR, the tumor recurred in 5 patients (6.8%). The multivariable analysis showed that male sex, multiple tumors, and first-line treatment failure were significantly related to treatment failure (p=0.03, p=0.05, p=0.03, respectively). CONCLUSION: CR of primary cMALToma was achieved using various therapeutic strategies. First-line treatment failure and multiple tumors were associated with treatment failure, although the numbers of cases that failed are too small to draw definitive conclusions.