Overall Survival as an Endpoint in Cutaneous T-Cell Lymphoma

To the Editor:

In a recent issue of Blood, Jones and Wilson1 and Kurzrock et al2 exchange differing views as to the value of total skin electron beam radiation (TSE) in the management of cutaneous T-cell lymphoma (CTCL). Much attention is given to overall survival rates; I believe this attention is misplaced.

CTCL is overall an indolent lymphoma. Patients who fail on initial treatments such as topical therapy, PUVA, and TSE are then usually treated with a number of systemic agents. Thus, their long-term survival is greatly influenced by the efficacy, or lack thereof, of the subsequent therapy. There is little doubt that a greater reduction of tumor burden by one treatment versus another will contribute to long-term survival, but the survival duration will still be confounded by whatever subsequent therapy might be used.

In their report on TSE for CTCL,3 Jones et al provide data with regard to relapse-free as well as overall and cause-specific survival. However, with regard to topical therapy, relapse-free survival has limited significance because patients treated topically commonly relapse after discontinuing treatment following clearing and then re-respond to the same treatment. Additionally, recent experience shows that multiple courses of TSE can be used.4 

I concur with the view of Dillman5 that: “Unless one is limiting trials to patients with overwhelming disease who will receive no additional cancer therapy, or to a patient population for whom there will be no other trials and there are no known effective treatments, measurement of overall survival is probably an inappropriate endpoint for any type of treatment.” I favor “failure free survival” as the most meaningful endpoint for evaluation of treatment.