Long-term survival in patients with metastatic melanoma treated with DTIC or temozolomide

Abstract

Background: Patients with metastatic melanoma typically have a poor outcome; however, a small proportion of patients achieve long-term survival (LTS). It is unclear how often LTS is related to sensitivity to chemotherapy.

Methods: All patients with metastatic melanoma treated with either dacarbazine (DTIC) or temozolomide (TMZ) at the British Columbia Cancer Agency (BCCA) from January 1, 1988 to February 1, 2006 were identified through the BCCA pharmacy electronic database, which was then linked to the surveillance and outcomes unit to identify patients with LTS, defined as survival > or =18 months following chemotherapy.

Results: In total, 397 patients were treated with either DTIC (n = 349) or TMZ (n = 48) and 43 patients (10.8%) were identified with LTS. Two additional patients with LTS were added prior to 1988 for a total of 45 patients. The 5-year overall and progression-free survival rates for patients with LTS were 33% and 16%, respectively. In total, 16% had a complete response (CR) to chemotherapy, which was the only factor identified that correlated with survival in the multivariate analysis. However, most patients with LTS had an incomplete response to chemotherapy.

Conclusions: LTS occurs in select patients who achieve a CR to chemotherapy. However, this occurs in only a minority of patients and, in most cases, the longer survival is likely the result of indolent disease biology or host factors.

Figure 1.

Identification of long-term survivors with metastatic melanoma treated with dacarbazine (DTIC) or temozolomide. ^aNot included in determination of frequency of long-term survivors.

Figure 2.

Long-term survival in patients with metastatic melanoma treated with DTIC or temozolomide: (A) Progression-free survival; (B) Overall survival.

Figure 3.

Survival according to response to chemotherapy: (A) Progression-free survival; (B) Overall survival. %Abbreviations: CR, complete remission; PD, progressive disease; PR/SD, partial remission/stable disease.