Society’s portrayal of a cancer patient often involves hair and weight loss, a gaunt, pale face, and a general look of illness. This image is common, not only due to the cancer, but to its modern treatments: chemotherapy and radiation. While sometimes effective, they indiscriminately destroy healthy cells in addition to cancer cells, leaving patients with daunting side effects. The search for more effective, tolerable therapies has led scientists back to something that has naturally evolved to target and kill abnormal cells — the immune system.
“Your immune system is so smart, it makes sense that it is able to fight cancer cells,” says Roxana Dronca, M.D., a cancer researcher at Mayo Clinic in Rochester, Minnesota.
Researchers have made strides in cancer immunotherapy, but an important issue remains: predicting which patients will respond to the therapies. Dr. Dronca and her colleagues have discovered a potential answer to this issue for a promising immunotherapy called PD-1 blockade.
Dr. Dronca’s group found that the number of tumor-targeting immune cells in the blood correlated with whether patients with metastatic melanoma, a serious skin cancer, responded to PD-1 blockade. The finding may help clinicians make informed decisions about how to best treat these patients, and may be a time-, side-effect-, and money-saver for the patients themselves. Ongoing studies at Mayo aim to test this finding in additional patients, as well as different types of cancers.
As for the excitement about the potential of immunotherapy? Take it from someone who works with it on the basic science and clinical sides.
“It’s amazing,” says Dr. Dronca, “I think it’s actually, as the FDA has labeled it, a breakthrough in cancer therapy. It’s very exciting, and has changed the lives of many of my patients.”