Patients with decreased core muscle density have higher rates of their cancer spreading to distant parts of the body, reveals study from the University of Michigan Comprehensive Cancer Center.
These findings may also support the idea that the patient's biological response to a tumor is important in controlling the spread of melanoma. Patients whose systems are less able to mount a response may be more prone to their cancer spreading. In fact, young patients in poor health may have worse outcomes than older patients in good shape.
The researchers believe that identifying those patients who are at higher risk of poor outcomes could impact treatment decisions, including the success of new immunotherapy drugs. And potentially, if this degenerative muscle loss, called sarcopenia, can be reversed, patients might have better outcomes.
The study, which appears online in Annals of Surgical Oncology, looked at 101 patients treated for stage III melanoma at the U-M Comprehensive Cancer Center. Researchers examined CT scans for each patient to measure the area and density of a core muscle called the psoas, which runs along both sides of the spine.
They found that patients with lower muscle density had significantly higher rates of their cancer returning - regardless of factors such as the size of the tumor or the patient's age. Every 10 units of decreased muscle density translated to a 28 percent increase in recurrence. In addition, frailer patients had more complications from surgery to remove their cancerous lymph nodes.
Research has previously linked older age to worse outcomes in melanoma. These new results distinguish that it's the underlying vitality of the patient, not age, that really matters.
Many studies have looked at ways to reverse sarcopenia by focusing on diet and exercise.
"The big question is if we could reverse sarcopenia through better nutrition and exercise, would that lead to a decreased risk of recurrence in those patients?" says lead study author Michael S. Sabel, M.D., associate professor of surgery at the U-M Medical School.
In addition, researchers hope this information will help explain the limited success of new immunotherapy or cancer vaccine treatments.
"The data suggests that frailer patients may be less likely to respond to these forms of therapy. It is very possible that prior trials of vaccines or other immune therapies that didn't show an effect would have shown an effect if we had weeded out the patients unlikely to respond to therapy," Sabel says.
Researchers plan next to look at CT scans from patients treated in these trials to analyze whether the treatments were more effective in patients without sarcopenia.
Melanoma statistics: 68,130 Americans will be diagnosed with melanoma this year and 8,700 will die from the disease, according to the American Cancer Society