In Japan, The Japanese Association of Clinical Cancer Centers (JACCCs) was established in 1965 by systematizing cancer-treatment-oriented hospitals. The core center of JACCCs is the National Cancer Center in Tokyo. In 1984, JACCCs created The “Improvement for Clinical Cancer Centers in Japan” Study Group (The Study Group) which has subsequently routinely evaluated the effectiveness of the therapy that is provided. In general, the 5-year (relative) survival rate is employed as an indicator of the treatment efficacy. The present survey used the PC software program KAP developed by Chiba Cancer Center in Japan, to calculate 5-year observed survival rates and the 5-year relative survival rates using Ederer II methods. The overall 5-year relative survival rates in patients with stomach (15,353 patients), colon (5,054), rectum (3,695), lung (10,153), breast (11,302) and cervix of the uterus (6,336) were 68.7%, 72.2%, 69.4%, 28.1%, 86.1% and 81.1%, respectively. The survival rates discussed so far are principally observed survival rates. The 5-year relative survival rate for those institutions that specialize in cancer treatment should become an index for Japanese cancer treatment.