Chemoimmunotherapy versus chemotherapy for metastatic malignant melanoma

Malignant melanoma, one of the most aggressive of all skin cancers, is increasing in incidence throughout the world. Surgery remains the cornerstone of curative treatment in earlier stages. Metastatic disease is incurable in most affected people, because melanoma does not respond to most systemic treatments. A number of novel approaches are under evaluation and have shown promising results, but they are usually associated with increased toxicity and cost. The combination of chemotherapy and immunotherapy has been reported to improve treatment results, but it is still unclear whether evidence exists to support this choice, compared with chemotherapy alone. No language restrictions were imposed.

To compare the effects of therapy with chemotherapy and immunotherapy (chemoimmunotherapy) versus chemotherapy alone in people with metastatic malignant melanoma.

We searched the Cochrane Skin Group Specialised Register (14 February 2006), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005), MEDLINE (2003 to 30 January 2006 ), EMBASE (2003 to 20 July 2005) and LILACS (1982 to 20 February 2006). References, conference proceedings, and databases of ongoing trials were also used to locate trials.

All randomised controlled trials that compared the use of chemotherapy versus chemoimmunotherapy on people of any age, diagnosed with metastatic melanoma.

Two authors independently assessed each study to determine whether it met the pre-defined selection criteria, with differences being resolved through discussion with the review team. Two authors independently extracted the data from the articles using data extraction forms. Quality assessment included an evaluation of various components associated with biased estimates of treatment effect. Whenever possible, a meta-analysis was performed on the extracted data, in order to calculate a weighed treatment effect across trials.

Eighteen studies met our criteria and were included in the meta-analysis, with a total of 2625 participants. We found evidence of an increase of objective response rates in people treated with chemoimmunotherapy, in comparison with people treated with chemotherapy. Nevertheless, the impact of these increased response rates was not translated into a survival benefit. We found no difference in survival to support the addition of immunotherapy to chemotherapy in the systemic treatment of metastatic melanoma, with a hazard ratio of 0.89 (95% CI 0.72 to 1.11, p=0.31). Additionally, we found increased hematological and non-hematological toxicities in people treated with chemoimmunotherapy.

We failed to find any clear evidence that the addition of immunotherapy to chemotherapy increases survival of people with metastatic melanoma. Further use of combined immunotherapy and chemotherapy should only be done in the context of clinical trials.