PSK immunotherapy in cancer patients--a preliminary report.
A clinical trial was conducted by the Department of Radiation Oncology, Mackay Memorial Hospital, between 1981 and 1986, using PSK (Krestin) as an adjuvant immunotherapy to assess its potential benefit in cancer patients. The protocol called for a daily administration of 1 gram tid of PSK orally for at least a month upon completion of primary treatment for the tumor. A total of 67 patients were included in this study; 13 patients were excluded from evaluation because of noncompliance with the protocol. When three cases of toxicity were noted, PSK was discontinued for the three patients. Among the different groups of patients, nasopharyngeal carcinoma patients under PSK immunotherapy showed a significantly better survival when compared with historical controls (28% vs 17% five-year survival rate, p less than 0.05, generalized Wilcoxon test). It is therefore concluded that PSK can serve as an important adjunct in the treatment of nasopharyngeal carcinoma.