"Melanoma is unfortunately one of the few cancers that has become more common over the last few decades, and when it becomes metastatic, there are very few treatment options," says Ravi Rao, M.B.B.S., Mayo Clinic oncologist and lead investigator of the study. "This is a good step towards better treating this cancer. We hope to continue to find treatment options that extend and improve life expectancy for patients." This study appears to have found one such option, with nearly half of the patients that received PC experiencing a clinical benefit of stable disease (19 percent) or tumor size reduction (26 percent).
The National Cancer Institute reports a 2.4 percent increase in the incidence of melanoma between 1992 and 2002. New cases are diagnosed in about 60,000 people each year in the United States, and almost 8,000 die because of metastasized melanoma. Because they know that most therapies provide palliative as opposed to curative options, researchers at Mayo Clinic Cancer Center consider developing more effective curative treatment options to be a priority.
Dr. Rao and his co-investigators examined the records of 31 MM patients at Mayo Clinic who were treated with the PC combination between March 2003 and January 2005. These patients had previously received (and failed) an average of two treatments, including vaccine/immunotherapy. Interestingly, the researchers found that this combination benefited even those patients in whom temozolomide (currently the most commonly used chemotherapy drug for melanoma) failed.
Because the data was collected from the records of patients treated previously and was not part of a set treatment regimen, the schedule and dosage of PC varied. However, the researchers believe that using the drugs weekly (compared to once every three weeks) makes the combination more tolerable, and the researchers prefer that option.
"Other recent studies in the U.S. and Germany looking at combinations that included PC, indicated that there is some clinical benefit from this combination," says Dr. Rao. "Combined with our results, we believe that the PC combination truly has a beneficial role, especially for patients who've had poor results from other treatment options.
"However, this study is retrospective in nature, and further studies are needed to fully understand the impact of this combination on the survival of patients with metastatic melanoma," he says. Dr. Rao also notes that several additional trials using this drug combination are being planned, including some at the Mayo Clinic Cancer Center.
Others involved in the study included Shernan Holtan, M.D.; James Ingle, M.D.; Gary Croghan, M.D., Ph.D.; Lisa Kottschade; Edward Creagan, M.D.; Judith Kaur, M.D.; Henry Pitot, M.D.; and Svetomir Markovic, M.D., Ph.D.
For more information on melanoma treatment and research at Mayo Clinic, go to www.mayoclinic.org/melanoma.
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Cancer