The previously cited factors of peculiarities of the lesion and lack of follow-up, technique, and limited competence of the examiner apply to gastroscopy as well as to x-ray and cytologic studies.

Certain areas of the stomach are relatively "blind" at times for the gastros-copist, including:

1. The pylorus

2. The lesser curvature surface of the antrum

3. Parts of the cardia and adjacent lesser curvature

4. Parts of the posterior wall

5. The fundus adjacent to the diaphragm

It should be emphasized that the word "blind" is used here in a relative sense. There is wide variation in the manner and degree to which the stomach can be visualized.

Exploratory Laparotomy

Not infrequently the only way in which a diagnostic dilemma can be resolved is by means of surgical exploration, direct visualization, and possibly frozen section of the lesion in question. Not only should the physician be prepared to make a recommendation for such a course of action occasionally, but he must also be certain that it is done promptly. If the initial steps to diagnosis have been carried out without delay and no diagnosis is possible, it is unwise to dissipate precious weeks or months in fruitless repetitions of equivocal studies or in "observation." Exploratory laparotomy in competent hands carries a very low rate of morbidity and mortality.

Lesser Steps To Diagnosis

These have already been referred to in the section on the screening of the asymptomatic individual. They are, of course, not diagnostic of stomach cancer, but they may add their weight in an important way to the evidence for or against the diagnosis.

Gastric Analysis

Approximately 90% of patients with stomach cancer will have diminished or absent gastric acid. Therefore, anacidity in a stomach cancer suspect increases the likelihood of the diagnosis, and evidence of acidity diminishes it.

Guaiac Test

Over 80% of patients with established stomach cancer have occult blood in the stool if this is carefully tested for. Thus positive or negative tests may contribute for or against the diagnosis in the individual patient.

Hemoglobin Or Hematocrit

It is difficult to give an estimate of the frequency of anemia in stomach cancer but most patients will demonstrate it at some stage of the disease.

Other Studies

Other studies have been proposed as being helpful or even critical in the detection or diagnosis of stomach cancer. These include the use of electrogastrog-raphy, determination of urinary uropepsin secretions, and estimation of the uptake of radioactive phosphorus by the lesion. These cannot be recommended for use in the diagnosis of the usual case of stomach cancer.

Differential Diagnosis

In the strict sense of the word, the differential diagnosis of stomach cancer should include all those conditions which could produce any of the symptoms, physical signs, and x-ray findings encountered in this disease.

From the practical standpoint of frequency and importance, however, the following should head the list:

1. Benign peptic ulcer

2. Benign tumors

3. Gastritis, especially in the antrum

4. Pyloric obstruction due to spasm or hypertrophy

5. Hypertrophy of the rugae

6. Obstruction at the cardia due to spasm, hypertrophy, or esophageal carcinoma

Much has been written about the features that may serve to distinguish these from stomach cancer, but the malignant lesion can be identical in every respect to the entities listed. Most often, therefore, the answer lies in a systematic progression through the steps to diagnosis noted previously. Occasional errors on the side of overdiagnosis in the case of benign disease will be more than compensated for by the experience of uncovering occult, early stomach cancer.