title: Incidence of second neoplasms in patients with MALT lymphoma: no increase in risk above the background population.
abstract: BACKGROUND
  Lymphomas of mucosa associated lymphoid tissue (MALT) are a special type of extranodal lymphoma, possibly related to chronic antigenic stimulation. Increased cancer susceptibility may also contribute to the development of MALT lymphoma (MALToma). It has been suggested that patients with MALToma have an increased incidence of other malignancies.
  
  
  METHODS
  We retrospectively reviewed the histology and clinical records of 147 patients with MALToma, including 51 cases of gastric MALToma. 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 year.
  
  
  RESULTS
  A total of 41 tumors occurred in 32 patients (21%), including 22 solid tumors. The incidence of solid tumors in the gastric MALToma group was 15%. Seven patients had two or more second malignancies. Cancer occurred before diagnosis of MALToma in 29 cases, concurrent with MALToma in three, and after MALToma in nine. Follow-up of the surviving patients is short (median 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 previous reports. However, when compared to an age-matched population followed for the same period of time, MALToma patients do not appear to have a statistically significant increased rate of cancers.
authors.affiliation: Division of Medical Oncology, British Columbia Cancer Agency and the University of British Columbia, Vancouver, Canada.
authors.forename: W Y
authors.initials: WY
authors.lastname: Au
authors.forename: R D
authors.initials: RD
authors.lastname: Gascoyne
authors.forename: N
authors.initials: N
authors.lastname: Le
authors.forename: D S
authors.initials: DS
authors.lastname: Viswanatha
authors.forename: R J
authors.initials: RJ
authors.lastname: Klasa
authors.forename: R
authors.initials: R
authors.lastname: Gallagher
authors.forename: J M
authors.initials: JM
authors.lastname: Connors
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia / Q000453:epidemiology; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D015994:Incidence; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D012878:Skin Neoplasms / Q000453:epidemiology; D013274:Stomach Neoplasms / Q000453:epidemiology; D015996:Survival Rate