Prognosis of primary thyroid lymphoma: demographic, clinical, and pathologic predictors of survival in 1,408 cases.

BACKGROUND: There is a paucity of data regarding prognosis of primary thyroid lymphoma (PTL), with only case reports and institutional series reported. This is the first population-based study of PTL in the United States.

METHODS: PTL patients were identified in the SEER database. Bivariate (chi(2), Kaplan-Meier, and log rank) and multivariate (Cox proportional hazards) analyses were used to assess the associations between patient characteristics and survival.

RESULTS: A total of 1,408 patients were identified over 32 years of follow-up (median, 3.75 years). Mean age was 66 years; 75% were female and 93% white. Overall, 98% had non-Hodgkin's lymphoma; 68% had diffuse large B-cell, 10% follicular, 10% marginal zone, and 3% small lymphocytic. A total of 88% had stage I-II disease. Median survival was 9.3 years. On bivariate analysis, older age, single marital status, stage II-IV disease, histology (large B-cell, follicular, or other non-Hodgkin's), earlier year of diagnosis, lack of prior malignancies, and no radiation/surgery predicted worse survival. Age >or=80 years, advanced stage, no radiation/surgery, and large B-cell or follicular histology predicted worse prognosis in multivariate analysis.

CONCLUSION: Older age, advanced stage, histologic subtype, and lack of radiation/surgical treatment are associated with worse survival. Thyroid resection offers benefit only for patients with stage I disease. Management of PTL requires multidisciplinary collaboration.