High Relapse Rate in Patients with MALT Lymphoma Warrants Lifelong Follow-up

Background: B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) is thought to be an indolent disease, with a good prognosis following various forms of treatment. Little, however, is known about the rate and pattern of relapse following successful treatment. Patients and Methods: We have analyzed time to and pattern of relapse in patients with MALT lymphoma, along with investigation of t(11;18)(q21;q21), t(1;14)(p22;q32), and t(14;18)(q32;q21) involving IGH/MALT1, trisomy 3, and trisomy 18. Eighty-six patients achieving complete remission (CR) after initial therapy with sufficient follow-up data were available. Primary site of disease was the stomach (n = 36), salivary gland (n = 19), ocular adnexa/orbit (n = 12), lung (n = 8), thyroid (n = 5), breast (n = 3), liver (n = 2), and skin (n = 1). Results: Thirty-two patients (37%) relapsed between 14 and 307 months (median 47 months) after initial CR. Ten relapses were local, whereas the remaining patients relapsed in a distant organ. Eight of 36 gastric versus 24 of 50 nongastric MALT lymphomas (P = 0.02) relapsed. Five patients had a second recurrence 26 to 56 months after a second CR. Relapse rates were not related to forms of initial treatment. Chromosomal aberrations were detected in 14 of 28 (50%) relapsing patients, and chromosomal alterations were identical at diagnosis and relapse. No significant association of any of the genetic changes investigated with relapse was found. Interestingly, patients with t(11;18)(q21;q21) had a significantly longer median time to relapse (76 months) than patients without this translocation (29 months; P = 0.012). Conclusions: In view of the late relapses seen in our series, lifelong observation of all patients treated for MALT lymphoma seems to be required.