Incidence of second neoplasms in patients with MALT lymphoma: No increase in risk above the background population

Background: Lymphomas of mucosa associated lymphoid tissue (MALT) are a spe cial type of extranodal lymphoma, possibly related to chronic antigenic sti mulation. Increased cancer susceptibility may also contribute to the develo pment of MALT lymphoma (MALToma). It has been suggested that patients with MALToma have an increased incidence of other malignancies. Patients and methods: We retrospectively reviewed the histology and clinica l records of 147 patients with MALToma, including 51 cases of gastric MALTo ma. The incidence of any second malignancy was confirmed with a provincial registry. The relative rates of cancer, excluding MALToma, were calculated relative to the background population of the same age group and secular yea r. Results: A total of 41 tumors occurred in 32 patients (21%), including 22 s olid tumors. The incidence of solid tumors in the gastric MALToma group was 15%. Seven patients had two or more second malignancies. Cancer occurred b efore diagnosis of MALToma in 29 cases, concurrent with MALToma in three, a nd after MALToma in nine. Follow-up of the surviving patients is short (med ian 17.6 months). The relative rate from birth of a second malignancy was 0 .86 in the whole group (90% confidence interval (CI): 0.62-1.16) and 0.95 ( 90% CI: 0.55-1.54) in the gastric MALToma group. The rates were roughly the same if skin cancers were excluded. Conclusions: The incidence of second cancers in this series is similar to p revious reports. However, when compared to an age-matched population follow ed for the same period of time, MALToma patients do not appear to have a st atistically significant increased rate of cancers.