Radiation therapy in indolent primary cutaneous B cell lymphoma: a single institute experience.

To report the clinical results after definitive radiotherapy (RT) for indolent primary cutaneous B cell lymphoma (pcBCL). The data concerning all patients treated for indolent pcBCL with RT with a curative intent between 1992 and 2012 were reviewed. All cases were (re)classified according to the World Health Organization (WHO) guidelines. A total of 42 patients with biopsy-proven primary cutaneous follicle center lymphoma (pcFCL) and primary cutaneous marginal zone lymphoma (pcMZL) were included. The median follow-up is 9.5 years. Treatment with RT resulted in complete response (CR) in all patients. Eight patients showed one or multiple relapses confined to the skin. No in-field recurrences were observed. For the entire cohort, the 10-year relapse-free survival (RFS) and overall survival (OS) were 71.1% and 87.1%, respectively. Univariate (UA) and multivariate (MA) analysis revealed extra-trunk primary lesion (MA) and multiple lesions (UA) as unfavorable prognostic factors. The 5-year RFS rate for patients with trunk lesion was 89.4% versus 66.9% for those with other location (p = 0.02). The 5-year RFS rates were 83.5 and 57.1% in case of single and multiple lesions (p = 0.04). An excellent survival can be achieved with definitive RT in indolent pcBCL. Patients with multiple and extra-trunk primary cutaneous lesions probably warrants intensification of therapy. Prospective studies are mandatory.