Can platelet-lymphocyte ratio be used to assess the effects of chemotherapy on breast cancer patients?

The ratio of platelets to lymphocytes in the blood is a known independent marker for predicting the outcomes in breast cancer patients. Platelets are cells in the body containing the largest quantity of growth factors. These growth factors are produced in large quantities by cancer cells and help the cancer grow and spread. Lymphocytes are cells that are part of the immune system, and they fight to stop cancer growth. If there are too many platelets compared to lymphocytes, then this is a high platelet-lymphocyte ratio (PLR). In many types of cancer a high PLR has been thought to indicate a less favorable outcome compared to a low PLR.

Few studies have examined the relationship between the PLR and sensitivity to chemotherapy. Whether the PLR is a predictor of the therapeutic effects of chemotherapy in breast cancer patients is unclear.

This study included 177 breast cancer patients with early-stage breast cancer. They were treated with chemotherapy drugs followed by surgery. The PLR was measured in each patient. 67 patients were found to have a high PLR and 110 patients had a low PLR.

The low PLR group included significantly more patients over the age of 56 and postmenopausal women than the high PLR group. The low PLR group had a better response rate to the chemotherapy and longer survival rates compared to the high PLR group. The study also found that patients with high PLR and cancer spread to the lymph nodes had less favorable outcomes.

The study concluded that a low PLR was more sensitive to the effects of chemotherapy, suggesting that it could be used to predict the effects of chemotherapy in breast cancer patients. 

There was no control arm in the study.