Blood Test Predicts Prognosis in Aggressive Skin Cancer

A routine blood test may help predict survival in patients with an aggressive form of skin cancer known as Merkel cell carcinoma.

The enumeration of the absolute lymphocytes count (ALC) in the blood is routinely monitored and patients with Merkel cell carcinoma who had low numbers of lymphocyte do not live as long after treatment as those with higher lymphocyte counts.

Physicians at Fox Chase Cancer Center (Philadelphia, PA, USA) reviewed medical records of 64 patients treated for Merkel cell carcinoma between 1992 and 2010. All patients had had their blood analyzed the month before surgery, chemotherapy, or radiation. Merkel cell carcinoma is a rare and aggressive type of skin cancer, usually striking older people and those with weakened immune systems.

Approximately two-thirds of patients had a normal ALC. Along with having longer overall survival; 67% of the patients were much more likely to be disease-free 60 months later than the 24% with a low ALC. The difference between the groups was remarkable. Among people whose ALC was below the cutoff of 1,500 cells/cubic millimeter of blood, half survived 25 months or less after surgery, chemotherapy, or radiation. Among those with ALCs in the normal range, half lived close to 100 months or more following treatment. Disease-free survival was also much longer in patients with higher ALCs.

Matthew Johnson, MD, a resident physician and lead author of the study, said, "Since ALC has been tied to prognosis in other types of cancer, we were expecting to see some difference between patients with high and low counts, but it was definitely a bigger difference than what we were anticipating. Doctors routinely check a patient's ALC as part of a standard blood count. They just typically don't know how to interpret those particular results. However, if a patient's ALC is particularly low, there's little the doctor would do differently to treat Merkel cell carcinoma, since such an aggressive cancer is always treated aggressively. But many patients believe it's helpful to know their prognosis.” ALC provides patients with some information about how long they may have left. The study was presented on October 3, 2012, at the American Society for Radiation Oncology’s 54th Annual Meeting held in Boston (MA, USA).

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