Mammography in Surgical Practice

Peter I. Pressman, MD, FACS, New York, New York

In 1960 Egan [I] reported his experience with 1,000 mammograms in which the accuracy was 97 per cent. This stimulated interest in the technic and mam- mography has become readily available throughout the United States. Initially, physicians in practice were unwilling to recommend a biopsy solely on the basis of a radiologic report of a malignancy in the absence of a clinically palpable tumor. The pendulum has swung, however, so that now there is an increas- ing dependence on the x-ray study and a reluctance to biopsy if the mammography report is “nega- tive.”

Women have been encouraged to do regular self- examination of the breast so as to detect abnormal lumps at the earliest possible time and then to con- sult their physicians. An x-ray examination is often obtained as a part of the evaluation usually by a gynecologist or an internist. Because of the highly publicized results of screening mammography, where unsuspected and impalpable cancers have been de- tected radiographically, many physicians and their patients have come to rely on a negative x-ray report as assurance that no malignancy is present. Subtle lesions detected by women or by their physicians have been allowed to enlarge before a surgical con- sultation or biopsy is recommended because of the false sense of security afforded by an x-ray exami- nation reported as a negative study or describing a lesion as benign.

The present study was undertaken to determine the accuracy of mammography in a series of patients whose breast cancers were documented by biopsy and to assess the role mammography played in this se- lected group. It is not a statistically significant study, but the case material and variables are common to surgical practice and the findings should be of in- terest to surgeons, gynecologists, and internists.

From the Breast Service, Beth Israel MedIcal Canter, New York. New Ywk.

Reprint requests should be ad&eased to Peter i. Reasman, MD, Dew- mot of Surgery. Beth Israel h4edlcal Center. 10 f&hart D. Pertman Place, New York, New York 10003.

Material and Methods

One hundred consecutive patients who underwent op- eration for breast cancer were examined preoperatively either by mammography or xeroradiography. Ninety-four patients had been referred because of the presence of an abnormality on physical examination of the breasts and six patienta were operated on solely because of an abnormal mammogram. There are 106 cancers included in this study because six patients were proved to have simultaneous bilateral breast malignancies.

The patients were referred from a variety of sources and the x-ray examinations were done by radiologists in dif- ferent settings. In New York City mammography is per- formed in hospitals, in screening centers for breast cancer, as a part of a general radiology practice, and also by phy- sicians who specialize in mammography.

The age distribution of these patients is fairly typical for breast cancer (Table I) and includes a single male patient. The preoperative mammogram was reported as being negative (demonstrating no pathologic features) in thirty-three instances (31 per cent). In eleven examinations (10 per cent) the radiologist incorrectly described the lesion as being benign, either as a cyst or a fibroadenoma. The presence of a malignancy was correctly diagnosed or the suspicion of a malignancy was raised in sixty-two exami- nations (59 per cent).

In this group of patients the accuracy of mammography in correctly diagnosing a maliiancy increased with the age of the patients. (Table I.) This confirms previous reports [2,3] that mammography is most valuable in patients older than forty years. In the four patients who were less than thirty-five years old (Table II) a malignancy was correctly identified in one patient (25 per cent), and if all patients less than forty years old are considered, the accuracy was 36 per cent. It is of particular interest to note that at all ages carcinomas were sometimes misinterpreted as benign le- sions.

Mammography was solely responsible for detecting a malignancy in the absence of a palpable tumor in seven instances. Four of these patients had x-ray examinations performed as a part of annual complete examinations be- cause they were more than fifty years old and one patient was examined at a Breast Cancer Screening Center. In two patients the malignancies were detected by mammography

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Mammography

TABLE I Mammographic Findings according to Age ~..________...__~ --_-.-_-.__ ..-_ ..____.__ ._ _

Positive Negative Benign Age No. of No. of _ ._

(yr) Patients Cancers No. % No. % No. % --__ -_-.--_--__--. -_

21-30 2 2 - - 2 100

31-40 11 12 5 42 6 50 1 8

41-50 21 22 11 50 9 41 2 9

51-60 29 30 19 63 8 27 3 10

61-70 29 32 23 72 8 25 1 3

71-80 7 7 3 43 2 29 2 29 81-90 1 1 1 100 - -

Total 106 62 59 33 31 11 10 _---_-----.-- --.-___.--. __

that was a part of an annual follow-up because of a previous mastectomy, and twice the malignancy was an unsuspected finding in the contralateral breast of a patient who was being operated on for a palpable cancer of the other breast. These last four patients are a part of the group of sixteen individuals with bilateral breast cancer in whom there were six simultaneous and ten metachronous malignancies.

Of particular importance is the role played by prior mammography in delaying a recommendation for a biopsy. This can be assessed since all of these patients have been cared for by a single surgeon and the individual case histories are well known. In twelve patients (12 per cent) an abnormality on breast examination had been found by a woman or by her physician and x-ray examination ini- tially performed from four to twelve months prior to op- eration. Because a cancer was not radiographically de- tected, biopsy had not been recommended. Only when the palpable tumors were observed to enlarge clinically were the patients referred and operated on. Six of the initial mammograms had been negative studies and six described benign lesions. Preoperatively, the x-ray examinations were repeated. Five of the six negative studies were unchanged, but four of the six benign appearing lesions were then in- terpreted as malignant. At the time the biopsies were performed three of these patients were inoperable, five patients were found to have extensive axillary metastases, and three patients had involvement of one to two lymph nodes. Only two patients had disease limited to the breast. In all of these cases the patients and their physicians had been reassured on the basis of the initial mammography that no serious pathologic features existed although a clinical abnormality had been present.

corllInents

The impact of mammography on the practice of medicine and in the earlier detection of breast cancer has been tremendous. Since Shapiro, Strax, and Venet (41 reported a one-third reduction in mortality from breast cancer in the mass screening program of the Health Insurance Plan of Greater New York, twenty-seven screening centers for breast cancer have been established throughout the United States. Pa-

TABLE II Mammographic Accuracy in Patients less than 40 Years of Age

Age Group (yr)

No. of Positive

Can- cers No. %

Negative Benign

No. % No. %

<35 4 1 25 1 25 2 50

<40 14 5 36 6 43 3 21 -_-_--.-- .------ ----.

tients are frequently referred to these centers because of the availability of excellent x-ray and thermo- graphic equipment and there is a tendency to forget the importance of the physical examination that is also performed. In an excellent study by Venet et al (5) the contributions of the separate modalities have been defined. Of 132 cancers studied, 59 were diag- nosed as a result of the clinical evidence alone, 44 on radiologic evidence alone, and 29 when both modal- ities indicated the need for biopsy. Omission of the clinical examination would have resulted in the loss of 45 per cent of the breast cancers, and omission of the mammography 33 per cent. Additionally, in the age group of 40-49 years, omission of the clinical examination would have resulted in the loss of 61 per cent of the cancers detected.

Diagnostic mammography in clinical practice is an entirely different matter. The x-ray study is re- quested because a lump has been found and addi- tional information about its nature is being sought. To properly evaluate the x-ray report, the factors involved must be understood, such as the age of the patient, breast size and density, and the location of the lesion. Just as important is the setting in which the x-ray is performed. Mammography is done in the radiology departments of hospitals, as part of a general radiology practice and also by physicians who specialize in mammography. The equipment and the technics used differ. Frequently, two standard views

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Pressman

of the breasts are taken by a technician and the ra- diologist who reports his interpretation may not be aware of the clinical findings. Some mammographers not only examine the patients, but place markers on a palpable lesion and take additional views in an at- tempt to define the palpable lesion radiographically. The wording of the reports also varies and may in- clude the statement that “the accuracy of mam- mography is 85 to 90 per cent” or that a “negative mammogram does not mean that a cancer is not present.” All of these variables must be known. A mammogram is not just another x-ray film. It is a special study which is extremely difficult to do well and it must be interpreted as any other laboratory test in medicine. If it is a negative study, it is non- contributory and one must act on the clinical find- ings.

Summary and Conclusions

The importance of clinical examination in diag- nosing cancer of the breast has been emphasized in a series of 100 patients operated on in a surgical practice. The 59 per cent accuracy of diagnostic mammography may not be the best that can be achieved, but since the x-ray studies were performed in varied settings, the results are probably compa- rable to common practice in many communities. As a diagnostic test when a lump has been found in the breast, a negative study or the description of a benign lesion must not provide a false sense of security to the physician, as occurred in twelve patients, resulting in a delay of from four to twelve months in recom-

mending biopsy. As has been emphasized by Rose- mond [S], diagnostic mammography is an adjunctive method to physical examination; it does not rule out cancer and must not substitute for biopsy of a pal- pable lesion.

The greatest value of mammography was in de- tecting an unsuspected malignancy. In the present study six patients benefited from x-ray detection when their lesions were not palpable and the x-ray study was performed either as a routine examination or because the patients were considered to be in a high risk group. This study supports the concept of screening by mammography. It was of particular importance in examining the contralateral breast in women who have had breast cancer. It was most valuable in patients more than forty years old and least accurate in women less than thirty-five years old.

References

1. Egan RL: Experience with mammogaphy in a tumor institution; evaluation of 1000 studies. Rad&gy 75: 894, 1960.

2. Kieraldo J. Scare J. Jamplis R. Lee RH, Mackenzie AS: Mam- mographically detectable breast cancer. An eleven year ex- perience. Am J Swg 132: 150, 1976.

3. Shepard S, Seder P, Cooper D, el al: Mammography: an aid in the treatment of carcinoma of the breast Ann Swg 179: 749, 1974.

4. Shapiro S, Strax P, Venet L: Periodic breast cancer screening in reducing mortality from breast cancer. JAMA 215: 1777, 1971.

5. Venet L. Strax P, Venet W, Shapiro S: Adequacies and inade- quacies of breast examinations by physicians in mass screening. Cancer 28: 1546, 1971.

6. Rosemond GP: Mammography (editorial). JAMA 228: 874, 1974.

704 The Amwkan Journal of Surgary