Brazilian researchers have found that the addition of immunotherapy to chemotherapy for treating malignant skin cancer does not improve survival rates.

However, the combined treatment can generate some serious side effects in patient's body, the researchers revealed.

"No difference was seen in survival rate and toxic effects were increased, when immunotherapy was added to chemotherapy, researchers wrote in recent issue of The Cochrane Library.

The study, involving 2,625 patients, was conducted at the research center Onco-Evidencias in Sao Paolo.