Background: Developed as a biological response modifier (BRM), lentinan mitigates patients' symptoms by boosting the immune system. In combination with S-1 (tegafur, gimeracil, oteracil), lentinan is reported to mitigate adverse reactions to therapy for unresectable recurrent gastric cancer and prolong survival. However, there are few reports from actual clinical practice, and precise methods of using lentinan have not yet been established. This study retrospectively examined the usefulness of lentinan in patients.
Patients and methods: The subjects of this study were 39 patients who were diagnosed with unresectable gastric cancer, based on preoperative examinations or findings at laparotomy in our Department. These patients underwent S-1/paclitaxel therapy. Nineteen of the patients received lentinan while 20 did not, and these two groups of patients were compared.
Results: There were no significant differences in patients' characteristics such as the male:female ratio, age at the start of chemotherapy, and staging classification of the 19 patients receiving lentinan and the 20 patients not receiving lentinan. Comparison of the two groups revealed no significant differences in overall survival time, but comparison of the duration of therapy revealed that therapy tended to be longer for the group taking lentinan than the group not taking lentinan. Adverse events were noted in 61.5% (24 patients) of the total patients group; such events tended to occur less frequently in the group receiving lentinan.
Conclusion: Lentinan inclusion in therapy did not seem to prolong survival. Nevertheless, the duration of therapy tended to be longer for patients taking lentinan. This may be due to the fact that adverse events tended to occur less frequently in these patients during therapy. A decline in the incidence of adverse events increases the duration of therapy and improves the patients' quality of life (QOL); it may also prolong survival. Optimal methods of using lentinan need to be established.