The addition of immunotherapy to chemotherapy for malignant skin cancer that has spread does not improve survival rates, researchers have found, and patients have more serious side effects, such as anemia, when the two treatments are combined.
Malignant melanoma develops when cancer grows in the cells responsible for skin color, and is one of the most aggressive forms of skin cancer. Having unusual moles, exposure to sunlight and being fair-skinned are thought to place people at higher risk.
The use of oral or injected chemotherapy drugs to kill melanoma cancer cells can be effective if the cancer is diagnosed early, but once it has spread — metastasized — it is almost always fatal.
According to the National Cancer Institute, each year about 53,600 people in the United States are diagnosed with melanoma and 7,400 die from it. The incidence of melanoma has risen an alarming 3 percent a year since 1981, according to the Centers for Disease Control and Prevention.
Researchers have hoped that a combination of immunotherapy — treatment that bolsters or stimulates patients' immune systems — and chemotherapy might be an option for people with malignant melanoma.
Authors led by Andre Sasse, M.D., at the research center Onco-Evidencias in Sao Paolo, Brazil, reviewed 18 studies of 2,625 patients who were treated with either chemotherapy alone or a combination of chemo- and immunotherapy.
"No difference was seen in survival rate and toxic effects were increased" when immunotherapy was added to chemotherapy, the researchers write.
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The review examined two kinds of immunotherapy combined with chemotherapy, interferon and interleukin-2. Of the 11 studies that reported on side effects from chemoimmunotherapy, eight showed blood disorders and flu-like symptoms resulting from the combined treatment. In four studies that used interleukin-2 without interferon, patients had more blood side effects after treatment.
Jedd Wolchok, M.D., an oncologist at Memorial Sloan-Kettering Cancer Center, said that it is difficult to tease out which of the two immunotherapy agents might be responsible for the side effects to patients' blood.