Phytohaemagglutinin responsiveness of peripheral lymphocytes and survival in patients with primary breast cancer.

The response of peripheral blood lymphocytes from 153 breast cancer patients to the T-cell mitogen phytohaemagglutinin (PHA) was measured prior to surgery and patients assigned to either high (Hi/PHA) or low (Lo/PHA) PHA response groups. Patients were followed up for between 8 and 12 years, or until death. Clinical characteristics were similar in Hi/PHA and Lo/PHA groups. In the 96 patients who received no postoperative adjuvant therapy, overall and relapse-free survival was significantly longer in Hi/PHA than in Lo/PHA patients (p less than 0.005, and p less than 0.025 respectively); relative risk of death within 12 years was 0.52 and of relapse was 0.64. In 47 patients who were treated with radiotherapy postoperatively, there was no correlation between the PHA response and overall or relapse-free survival. The implications of these findings for the selection of breast cancer patients for adjuvant treatment following surgery are discussed.