Survival Patterns among Chronic Lymphocytic Leukemia and Other Lymphoma Patients with Family History of Lymphoma.

Background. A role for genetic factors in chronic lymphocytic leukemia (CLL) is unequivocal based on evidence from multiply affected families, from case series, twin and case-control studies, and population-based registry studies. Similar characteristics have been observed for non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL). Population-based studies have found CLL, NHL and HL to co-occur in families. A few hospital-based series have explored survival outcomes in familial vs. sporadic CLL patients based on the hypothesis that genetic mechanisms involved in the causation of familial lymphomas might influence survival, however these have been based on small numbers with inconsistent findings. We have conducted a large study in Scandinavia including more than 41,000 lymphoma patients to quantify survival outcomes among familial vs. sporadic patients.

Methods. We used the population-based central Cancer and Multigenerational Registries in Sweden and Denmark to identify all CLL (n=7749), NHL (n=25801), and HL (n=7476) patients diagnosed 1958–2001, with linkable first-degree relatives. All relatives were linked with the Cancer Registries to obtain information on CLL, NHL, and HL. Using Cox proportional hazard models, we calculated hazard ratios (HRs) and 95% confidence intervals (CIs) as measures of overall survival for CLL, NHL, and HL patients with vs. without family history of lymphoma.

Results. We found 85 (1.1%) CLL, 207 (0.8%) NHL, and 96 (1.3%) HL patients with family history of lymphoma. Overall survival was similar for CLL (HR=1.24, 95% CI 0.93–1.67), NHL (HR=0.97, 95% CI 0.80–1.16), and HL (HR=0.78, 95% CI 0.51–1.19) patients with vs. without family history of lymphoma. Risk-estimates were similar when we calculated overall survival by age at lymphoma diagnosis (above vs. below median age), year at diagnosis (before vs. after 1987), and by sex. Consistent with the literature, including all CLL, NHL and HL patients, older age (p<0.001) and male gender (p<0.001) was associated with poorer survival. However, when analyses were restricted to patients with family history of lymphoma, only older age (p<0.005) remained significant.

Conclusions: Survival patterns were similar for CLL, NHL, and HL patients with vs. without family history of lymphoma, suggesting that familial lymphomas do not have an altered clinical course. Overall, there is no evidence at this time to modify therapeutic strategies for patients with CLL, NHL, or HL based solely on family history.