Radiotherapy and head and neck cancer. Role of lymphocyte respontse and clinical stage.

The mean number of lymphocytes, response to phytohemagglutinin (PHA), and response to concanavalin A (Con A) in whole-blood cultures for 106 patients with head and neck cancer were 83%, 73%, and 64%, respectively, of values for healthy control individuals. During radiotherapy, lymphocyte counts declined to 44% and PHA and Con A responses declined to about one third of control values. Lymphocyte counts slowly increased after treatment to 77% of control values after two years, but responses to mitogens remained at about 40%. Responses to PHA and Con A for 38 patients who lived beyond 18 months were significantly greater before and after treatment than responses for 39 patients who died within 18 months. In general, a poor pretreatment response to PHA and Con A correlated with a poor clinical course, whereas responses near the control level indicated a good clinical course.