ABSTRACT
<b>Purpose</b> : The purpose of this study was to determine how frequently cancer patients would be missed if primary care clinics do not participate in the Japanese National Cancer Survey, and to describe the characteristics of those cancer patients who would be missed.<br><b>Methods</b> : This research is a case series study. We collected cancer patients who were identified in Ryuocho-Kokuminkenkouhoken Clinic and Yuge medical clinic for 26 years and were registered in the Shiga Cancer survey. We then extracted the records of those cancer patients who would be potentially missed from the national cancer registry and investigated the background.<br><b>Results</b> : The total number of cancer patients registered was 441. Of these, 28 (6.3%) patients who did not admit to the hospitals may be missed from the national cancer registry ; ten patients had their cancer diagnosed at an advanced stage and died at home without hospital admission. Two further cases had treatment for cancer (endoscopic resection) completed in the primary care clinic without hospital admission. Twelve patients only attend the hospital outpatient clinic for investigation and died at home without admission. And four patients received only CT scan examination and didn't attend the hospital outpatient clinic and died at home without admission.<br><b>Conclusion</b> : Primary care clinics that deal with the cancer patients treated completely in the clinics or home terminal care should participate in the Japanese National Cancer survey.