Improvement of survival in patients with primary cutaneous diffuse large B-cell lymphoma, leg type, in France.

IMPORTANCE: Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT), occurs in elderly patients and has been considered as a lymphoma with a poor prognosis, with estimated 5-year specific survival rates of approximately 50%. The hypothesis of an improvement in prognosis over time has not been studied.
OBJECTIVES: To evaluate this hypothesis in a large series of patients and investigate factors associated with prognosis as well as improvement in the prognosis. DESIGN, SETTING, AND PARTICIPANTS: A retrospective multicenter study was conducted including dermatology departments belonging to the French Study Group on Cutaneous Lymphoma. Participants were 115 patients with PCDLBCL-LT diagnosed between 1988 and 2003 (period 1) or between 2004 and 2010 (period 2). MAIN OUTCOMES AND MEASURES: Age, sex, period of diagnosis, number of skin lesions, tumor stage, tumor location (leg vs nonleg), lactate dehydrogenase level, type of therapy (with or without a combination of rituximab and polychemotherapy [PCT]), and outcome were recorded. Baseline characteristics and outcome were compared according to period of diagnosis and type of therapy. Prognosis factors were identified by univariate and multivariate survival analyses.
RESULTS: The mean age of the patients was 76.9 years, and 47% of the patients were older than 80 years. The 3- and 5-year specific survival rates improved between period 1 and period 2, from 55% to 74% and from 46% to 66%, respectively (P = .01). Patients had similar baseline characteristics during both periods, but rituximab-PCT regimens were administered to 88.5% of the patients in period 2 vs 16.7% in period 1 (P < .001). The 3- and 5-year specific survival rates were 80% and 74%, respectively, in patients who received a rituximab-PCT regimen compared with 48% and 38% in those who received less-intensive therapies. No significant difference was observed between both groups in age and baseline prognostic factors. In multivariate analysis, treatment without rituximab-PCT was the only adverse prognostic factor (odds ratio, 4.6 [95% CI, 2.4-9.1]; P < .001), whereas the number of skin lesions (P = .06) and location on the leg (P = .07) had only borderline significance. CONCLUSIONS AND RELEVANCE: A major improvement in the survival of patients with PCDLBCL-LT has occurred over time in France, mainly as a result of the use of intensive rituximab-PCT regimens in most patients, including very elderly ones. Until further prospective clinical trials are conducted, such regimens should be considered as the standard of care in these patients.