Can white blood-cell levels predict tumor response in rectal cancer?

This study investigated if a change in white blood cell (WBC) levels before or during chemotherapy and radiation therapy are associated with rectal tumor response. Researchers suggested that a decreased level of WBC is associated with improved tumor response in patients with rectal cancer.

Chemotherapy and radiation therapy before surgery is the standard treatment for patients with locally advanced rectal cancer. Prior studies showed that 10 to 15% of these patients have a complete tumor response after chemotherapy and radiation therapy before surgery. Additionally, good-responders have an improved survival when compared to non-responders. However, predictive factors for tumor response in patients who undergo radiation are yet to be found.

Inflammation has been described as a good prognostic factor and to be associated with improved survival. WBC levels are a good indicator of inflammation. Recent studies showed that WBC count is a prognostic factor for some solid tumors. However, it is not known if WBC has a predictive role in rectal cancer.

This study included 641 patients with rectal cancer who received chemotherapy and radiation therapy before surgery. WBC levels were measured before treatment and every week during the treatment period. Patients were followed-up for an average of 50.1 months.

Off 641 patients, 490 (76.4%) had a high WBC level and 151 (23.6%) had a low WBC level. A complete tumor response was more common in patients with low levels of WBC (23.8%) than in the high WBC group (12.2%). Patients with high levels of WBC had a 58.8% lower chance of a better tumor response. Also, patients with a high level of carcinoembryonic antigen (CEA; a tumor marker) had a 43.4% lower chance of a better tumor response.

The 5-year recurrence-free survival rate (patients alive from treatment to when cancer comes back) was higher (83.3%) in the patients with low WBC when compared to patients with high WBC (67.6%).

The study concluded that low WBC levels during chemotherapy and radiation treatment before surgery can predict a good tumor response.

This study did not account for patients with other diseases that could change their inflammation or WBC levels.