June 2 (Reuters) - Treatment with Bristol Myers Squibb's immunotherapies Opdivo and Yervoy prior to surgery for patients whose skin cancer had spread to lymph nodes had better outcomes than those who did not get the drugs before node removal procedures, according to data from a late-stage trial released on Sunday.

The study of 423 patients with stage 3 melanoma found that 83.7% of patients who received the immunotherapies before their surgery were alive without the disease worsening after 12-months.

The 12-month event-free survival rate in the patients who did not receive the so-called neoadjuvant treatment, but were treated with Opdivo for a year afterward, was 57.2%, researchers reported at the American Society of Clinical Oncology (ASCO) meeting in Chicago.

Around 58% of patients in the treatment arm had a complete pathologic response, meaning there was no sign of cancer in the removed lymph nodes, and they did not receive additional treatment.

The rest of the patients either received more Opdivo or Novartis' targeted drugs Tafinlar and Mekinist.

"This will likely change our practice," ASCO President Dr. Lynn Schuchter said in an interview.

"Many patients can just be treated with a very limited course, albeit it has a little more toxicity, but not have to complete a whole year... That's a really good outcome," she said. The study was sponsored by the Netherlands Cancer Institute and the Melanoma Institute Australia and funded by Bristol Myers Squibb and the National Health and Medical Research Council Australia. (Reporting by Michael Erman Editing by Bill Berkrot)