Evidence based medicine in biotherapy for malignant tumor

摘要

Biotherapy for cancer has become one of the most developing fields in the 21st century. Specific biotherapies, such as monoclonal antibodies or vaccine therapy for solid tumors, have been reported to show effects for chemotherapy refractory cancers, such as colon, breast, renal cancers, and melanomas, although solid evidence has not been confirmed by large-scale clinical trials for some of those therapies. Non-specific biotherapies, on the other hand, have been tested in many clinical trials. BCG and levamisole were the first agents to be tested in clinical study, and levamisole, combined with chemotherapy with 5-FU has shown a significant effect on survival for curatively resected colon cancers. In Japan, non-specific immunopotentiators, such as PSK, OK-432, and Lentinan have been widely tested in many clinical studies and randomized clinical trials (RCTs). A significant effect of PSK for survival was demonstrated in an RCT combined with chemotherapy for curatively resected gastric cancers and colorectal cancers. A meta-analysis of RCTs for gastric and colorectal cancer also showed the significant effect of PSK. Likewise, OK-432 has shown a significant effect on survival of lung, and gastric cancers in metaanalyses comparing immunochemotherapy with OK-432 to chemotherapy alone. The lentinan effect on survival was proved in small-size RCTs, and metaanalyses of those trials is underway. In conclusion, biotherapy using either specific or non-specific agents has proven effective for the treatment of cancer by evidenced-based medicine, and further new trials are expected to reconfirm their efficacy.