Nagato-machi and Wada-mura Nagano prefecture, are mountainous farm villages, with a population of about 8, 000. Over the past years, depopulation has progressed at a steady pace. The trend is still continuing and the average age of the populace is following an upward curve.
Since 1971, mass screening for early detection of stomach cancer has been conducted on a regular basis in Nagato-machi and Wada-mura.
While looking back upon the past 10 years, we made an attempt to analyze the cases of gastrectomy performed since 1978. Some of the cancer cases had been detected by the mass screening and the rest had been detected among the outpatients.
(1) The ratio of those who receive the mass screening tests to the total number of eligible inhabitants stood somewhere around 6% during the initial years, rose to the 10% level in 1976, and went up further to the 20% level in 1978, when stomach exams were started as part of the adult disease prevention scheme by the local health center of both town and village. However, the ratio of the elderly persons (65 and above) who come in for the checkup has been, and still is, notably low. This is one of the serious problems yet to be solved. It is serious in light of the fact that the average age of those outpatients who have been found contracting gastric cancer is 66.
(2) Since 1978, fiberscopy has been incorporated into the intensive examination course following the primary screening. During the past three years, seven cases of stomach cancer have been detected. The detection ratio was 0.23%. Six out of the seven cases were diagnosed as early stomach cancer.
(3) Between September 1978 and March 1981, 53 stomach cancer patients were treated in our hospital. Of the number, 10 had been screened by the mass survey and 43 had been diagnosed at the outpatient clinics. Except for three outpatients, 50 cases were operated.
We have reviewed the outcome of operations and prognoses of the operated cases and the following observations have been obtained
The average age of the patients who had been screened by the mass medical checkup is 62.0, and that of the outpatients is 64.9.
Eighty percent of the screened patients had no complaints.
Out of the outpatients, 75% had not undergone screening at any time previously.
Six patients out of the 50 had received screening five times or more. Five out of the six cases had early stomach cancer.
Curative operation could be performed on all of the patients who had been found in mass screening, but was possible in only 65% of the cases detected in the outpatient clinics.
Histologically, it was found, cancer had invaded no further than the submucosal layer in 80% of the screened patients as against 20% of the outpatients.
Metastasis to the lymph node had not taken place in 60% of the screened patients as against 40% of the outpatients.
As for the progress of cancer, 90% of the cases screened by mass survey had been at stage II or below as against 40% of the outpatients.
As of October 1981, 11 cases of the outpatients had died from cancer.