Seminars in Surgical Oncology 7:339-343 (1991)

Gastric Cancer Mass Survey in Chile

PEDRO LLORENS, MD

From the Gastric Cancer Center, Paula laraquemada Hospital, Santiago, Chile

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A Chilean publication in 1969 reported the 5-year survival rate of gastric cancer to be 12% of operated patients and only 3% of all patients diagnosed with gastric cancer. Encouraged by the excellent results obtained in Japan through a massive study of the population, Chile initiated in 1978 a program for massive detection of gastric cancer. From May 1978 to December 1986, 42,492 persons were screened under this system. Gastric cancer was detected in 0.43% in the massive group, and in 1.27% in the symptomatic group. The rate of early cancer detected per all gastric cancer was 14.69% in the former and 1 1.02% in the latter group. Gastric ulcer was found to be located more in the upper third of the stomach and less in the lower third, which may call attention in comparison with the foreign literature.

KEY WORDS: early gastric cancer, peptic ulcer, massive detection program

STUDY BACKGROUND The high mortality from gastric cancer in Japan places it as the highest risk country and explains its efforts to achieve early diagnosis of this disease and to improve its prognosis [ 1-41. The Japanese Health Ministry or- ganized a National Cancer Research and Treatment Program, which has been developed with excellent re- sults [5-lo].

In 1960 a massive study of gastric cancer was initi- ated in Japan, screening people in their forties or older, although some working groups included people 35 years of age. Many diagnostic centers were created for this purpose, operating independently or affiliated with hospitals. In order to reach people in rural areas, mobile units were employed. Such units were also used in urban areas with a high concentration of people liable to be examined [2,9,1 I].

Gastric cancer is a serious health problem in Chile because of both its high rate of recurrence and its very bad prognosis [12-161. Mortality figures rank Chile together with Japan as the highest risk countries for this disease (Table I). In 1969, a Chilean publication emphasized its very poor prognosis in analyzing 800 gastric cancer cases, of which only 70% could be treated surgically, with a 12% survival rate after 5 years of observation, while the survival for the whole group after 5 years was only 3% [15].

Encouraged by the excellent results obtained in Japan through a massive study-of the population, in May 1978 we started in Chile a program for massive detection of gastric cancer, as soon as the Japanese and Chilean authorities had signed a technical cooper- ation agreement for this purpose [ 14,17-191.

The Japan International Cooperation Agency pro- vided the necessary equipment and permanent and rotating technical assistance for the development of the program at the Gastric Cancer Diagnostic Center located in the Paula Jaraquemada Hospital in San- tiago and a similar center at the Van Buren Hospital in Valparaiso.

Also, during the development of this agreement, Japanese authorities donated mobile equipment spe- cially designed for mass examination for gastric can- cer, which allowed other hospitals in Santiago, i.e., Salvador Hospital, San Juan de Dios Hospital, and the Barros Luco Trudeau Hospital, to join in this research. This mobile unit at the same time enabled the screening of people over the length of the country, from Arica, Antofagasta, and Iquique in the north, to Talca, Chillan, and Concepcion in the south. The re- sults of this massive screening conducted in the Gas-

Address reprint requests to Dr. Pedro Llorens, Centro Diagnostic0 del Cancer0 Gastrico, Hospital Paula Jaraquemada, Santa Rosa No. 1234, Santiago, Chile.

0 1991 Wiley-Liss, Inc.

340 Llorens

TABLE I. Changes of Mortality Rates From Malignant Tumors in Chile, 1960 and 1980

Rate per 100,000

inhabitants Change -

Location 1960 1980 of rate %I

Total 99.9 101.9 2.0 + 2 Stomach 35.8 23.2 - 12.6 -38 Kidney and urinary 2.0 1.3 -0.7 -35

Leukemias 3.9 3.3 -0.6 - 15 Rectum 1.9 1.8 -0.1 -5 Thyroid 0.4 0.4 0 0 Uterus 1.9 8.0 +0.1 + I Esophagus 4.7 5.0 +0.3 + 6 Intestine 2.9 3.2 +0.3 + 10 Prostate 2.8 3.6 +0.8 +33 Lymphatics 2.2 3.0 +0.8 +36 Pancreas 2.1 2.9 +0.8 +38 Skin 0.5 0.7 +0.2 +40 Mamma 3.6 5.2 + 1.6 +44 Larynx 0.5 0.8 +0.3 +60 Bronchopulmonary 5.8 9.7 +3.9 +67 Gallbladder 3.0 6.9 +3.9 + 130

b 1 adder

tric Cancer Diagnostic Center are analyzed in this paper, excluding the Van Buren Hospital and mobile equipment studies.

An interesting epidemiologic fact is the persistent and progressive decrease of mortality risk from gastric cancer, which has been observed in several countries during recent years. In Chile, this change has been outstanding, and it seems that this fact bears no rela- tionship to the diagnosis and treatment of the disease. At the same time, the increase of mortality due to gallbladder cancer and bronchopulmonary cancer is particularly noteworthy [18,20].

In 1970, after some Chilean doctors pursued gradu- ate studies in Japan, the Chilean Association of Early Gastric Cancer was created. With great effort and sometimes having had to overcome serious equipment problems, they were able to diagnose the first cases of early gastric cancer in Chile, which were corroborated by means of the appropriate histopathological tech- niques and following the same systems used in Japan [12,13].

Although this effort represented a significant ad- vance, the early carcinoma percentage was low; even in the best series published, it did not exceed 6 8 % . This low percentage of early cancer diagnosed was probably due to the fact that these studies were per- formed on a symptomatic population and it is also probable that there were some limitations in the early anatomopathologic techniques on which diagnosis was based [12,13].

The program was completely gratis for the popula- tion studied, including people without social security, and it covered all stages of diagnostic and surgical treatment. This allowed reliable statistical results to be obtained, as there were no restrictions for approach- ing different socioeconomic groups and it was possible to perform repeated controls without major limita- tions [ 14,17-191.

METHODS AND RESULTS Persons around 40 years of age were studied, follow- ing a scheme similar to that employed in Japan (Fig. 1). Also persons around 40 years old with symptoms, referred from general medical clinics or from spon- taneous consultation, were included. None were in- cluded who had had surgical gastric treatment, nor those who at the time were under medical treatment due to gastric pathology.

From May 1978 to December 1986,42,492 persons were examined, 33,184 corresponding to the massive group and 9,308 to the symptomatic group (Table 11). In the massive group photofluorographic examination was normal in 75.84% (25,168), while in the sympto- matic group it was normal in 66.35% (6,176).

There were 261 cases diagnosed as gastric carci- noma, 143 of them within the group of massive exami- nation and 118 in the symptomatic group. As ex- pected, the gastric cancer percentage investigated in the massive group (0.430/) was lower than the percent- age in the symptomatic group (1.27%). The percentage of early cancer in the massive group was higher (14.69%) than in the symptomatic group (1 1%), which was consistent with what was to be expected (Table 111). It is important to point out that 29 cases of esoph- agus cancer were diagnosed in the massive group and 23 cases in the symptomatic group. Unfortunately all

MASS SURVEY (INDIRECT X-RAY and INTERVIEW)

X-RAY - d ENDOSCOPY

I- 4 DIAGNOSIS

LESION DISCARDED MEDICAL TREATMENT S~URGICAL TREATMENT

“I/ CONTROL

Fig. 1. 1978 to December 1986.

Flow chart of mass survey of gastric cancer in Chile, May

Gastric Cancer Mass Survey in Chile 341

TABLE 11. Gastric Cancer Mass Survey and Distribution of Symptomatic Cases by Age and Sex (May 1978 to December 1986)

Mass survey Symptomatic

Aee Women Men Total Men Women Total Total

40-49 7,851 4,686 12,537 1,284 1,804 3,088 15,625 50-59 7,562 3,831 11,393 1,228 1,880 3,108 14,501 60-69 2,648 2,133 6,78 1 790 1,258 2,048 8,829 70-79 1,486 737 2,223 381 533 914 3,137 80 or more 148 102 - 250 - 64 - 86 150 400

Total: 21.695 1 1,489 33,184 3,747 5,561 9.308 42.492

TABLE 111. Cancer Pathology Obtained by JICA" Program, May 1978 to December 1986 Gastric Cancer Diagnostic Center, Chilean Health Ministrv

Mass survey YO Symptomatic O/o Total

Number of persons examined 33,184 100.0 9,308 100 42,492 Gastric cancer 143 0.43 118 1.27 26 1

Advanced 122 85.3 105 89.0 227

Esophagus cancer 29 0.09 23 0.25 52 Gastric cancer plus esophagus cancer 172 0.52 141 1.51 313

*JICA, Japan International Cooperation Agency.

Early 21 14.7 13 11.0 34

TABLE IV. Benign Pathology Obtained by JICA Program May 1978 to December 1986: Gastric Cancer Diagnostic Center, Chilean Health Ministry

Mass survey Yo Symptomatic O/o Total Yo

No. of persons examined 33,184 100.0 9,308 100.0 42,492 100.0 Gastric ulcer 760 2.29 49 3 5.30 1,253 2.95 Multiple ulcers 225 0.68 173 1.86 398 0.94 Duodenal ulcer 326 0.98 162 1.74 488 1.15

Total peptic ulcers 1,311 3.95 828 8.90 2,139 5.04 Gastritis 1,302 3.92 405 4.35 1,707 4.02 Duodenitis 334 1.01 108 1.16 442 1.04 Polyps 162 0.49 67 0.72 229 0.54 Esophagitis 148 0.45 84 0.90 232 0.55

Gastric submucosal lesion 284 0.86 112 1.20 396 0.93 Total benign lesions 3,595 10.83 1,634 17.6 5.229 12.31

Other in esophagus 53 0.16 40 0.43 93 0.22

TABLE V. Gastric Ulcer Location According to Mass Survey of JICA and Chilean Health Ministry, May 1978 to December 1986

~~ Mass survey % Symptomatic Yo Total Yo

C 295 38.82 238 48.28 533 42.54 M 26 I 34.34 165 33.47 426 34.00 A - 204 26.84 - 90 18.26 294 23.46

Total: 760 493 1,253

were advanced cases. It is also important to point out the great number of benign diseases diagnosed both in the survey examination group (10.83%), and in the symptomatic group (17.6%) (Table IV).

The rate of gastric and duodenal ulcers in the mas- sive group was extraordinarily high (3.95%). A single gastric ulcer was observed in 2.29%, while multiple

gastric ulcers were found in 0.68%. Duodenal ulcer was diagnosed in 0.98%, and this rate could in reality be higher, due to lack of compression of the device for photofluorographic study. In the symptomatic group, there was a very high rate (8.9%) of peptic ulcer.

In Chile, gastric ulcer frequently presents itself in the upper third, and we think as years go by the rate

342 Llorens

of high location of gastric ulcer in our environment is increasing (Table V). For instance, the author pub- lished in 1975 a rate of 28.35% for gastric ulcer in the upper third; in the medial third it was 55.41%, and in the lower third, 16.23%, while in the massive group presently being analysed, the rate of gastric ulcers in the upper third was 38.82% and in the symptomatic group it was 48.28%. These percentages call for com- parison of our series with those reported in foreign publications [13,18].

False-negatives results, present in any technique, must be considered; they constitute a permanent in- centive to improve examination methods and their interpretation. In our series we have at least two cases of malignancy which were not diagnosed, i.e., a gastric cancer, Borrmann type I, in the upper third. This case was read again in indirect radiology, after endoscopic diagnosis, and the lesion was identified as a slight filling defect. There may be further false-negative cases, but they are very difficult to verify due to lack of periodical re-examination.

DISCUSSION We consider the results of this program, jointly carried out by the Japan International Cooperation Agency and the Chilean Health Ministry, as satisfactory be- cause at a low cost it was possible to detect a high percentage of malignant and benign lesions. We con- sider the indirect type of radiology an examination of excellent quality, high efficiency, and low cost, and this should be taken into account in public health plan- ning. The percentage of early gastric cancer diagnosed in the massive group is the highest in Chile and it is an incentive to go on with this type of research. Regional features in benign pathology, such as the peptic ulcer rate and the frequent location of gastric ulcer in the upper third, have been corroborated in this research [ 13,14,17-191.

The permanent participation of several Japanese professionals in the development of this program en- sures that standards are maintained, that we have ar- rived at our findings in a reliable way, and that they are interpreted from the same viewpoint. Active par- ticipation of many Chilean specialists represents re- search work and postgraduate training, which should be considered some of the most positive achievements of this program.

Results obtained by the employment of mass survey techniques on a group of symptomatic patients, should be considered in planning health assistance in countries with limited economical resources, such as ours. A criticism of programs for mass detection of gastric cancer is their high cost in relation to the per-

centage of pathology detected. This criticism is not justified if such a program is carried out in a sympto- matic population, permitting opportune and appro- priate study of patients. Although this is not an ideal situation, as the best prognosis is obtained with early lesions, preferably in their asymptomatic stages, op- portune diagnosis and treatment with modern surgical techniques, as developed in Japan, represent a definite advantage for our patients.

ACKNOWLEDGMENTS We wish to thank the Japan International Cooperation Agency and the Chilean Health Ministry for their sup- port in the establishment of this program. To the distin- guished Japanese physicians and Technologists who participated in carrying out the gastric cancer survey in Chile, and who generously shared their knowledge and expertise with us, our most sincere gratitude. Our spe- cial thanks for the excellent and devoted labor by medical, paramedical, and administrative personnel of the Gastric Cancer Diagnostic Center, and for the Gastroenterology and Digestive Surgery Services of the Paula Jaraquemada Hospital, that have made possible the realization of this program.

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