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

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.

To evaluate this hypothesis in a large series of patients and investigate factors associated with prognosis as well as improvement in the prognosis.

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).

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.

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.

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.