FILM-SCREEN : COMPARISON OF VIEWS

Lawrence W. Bassett, MD, Daniel H. Bunnell, MD, Richard H. Gold, MD, and Reza Jahanshahi, MS, Ill Los Angeles, California

The authors performed oblique, mediolateral, The incidence of cancer in the United States is and cephalocaudal film-screen mammographic on the increase. Over 130,000 new cases are diagnosed views for all 9,662 patients examined at the each year.' Mammography is the only method proved UCLA Medical Center from January 1, 1980 to effective in detecting clinically occult . December 31, 1985. In these patients, biopsies Support for mammographic screening is based on data yielded 172 cancers; 87 were nonpalpable. from past and ongoing mass screening programs in the There was a mammographic mass in 113, only United States and Europe, which have shown that calcifications in 38, and distortion or asymme- women undergoing periodic mammography may antici- try of breast parenchyma in 12. We retrospec- pate a one third reduction in their chance of dying from tively determined how each view contributed to breast cancer.2-3 Film-screen and xeromammography depiction of tumors: 125 cancers were seen on are the two generally accepted methods for performing all views, 10 on none, 11 on the oblique only, 4 on breast radiography.4 A survey conducted by the Amer- the mediolateral only, and 3 on the cepha- ican College of Radiology in 1986 indicated that the locaudal only. The remaining cancers were majority of radiologists were using film-screen mam- detected on various combinations of views. mography.5 For film-screen mammography, the breast is Cancers were missed in individual views usually imaged by directing the x-ray beam in a lateral, because of overlying dense tissue or because caudal, or lateral-oblique projection. We undertook a the tumor was outside the area depicted in the retrospective evaluation of the effectiveness of each of film. is performed with these views for breast cancer detection. two views of each breast. Oblique-cepha- locaudal two-view mammograms showed 158 MATERIALS AND METHODS cancers; mediolateral-cephalocaudal two-view Between January 1, 1980 and December 31, 1985, mammograms showed 151 cancers. 9,662 mammographic examinations were performed at the UCLA Medical Center. Every mammographic examination included a mediolateral, cephalocaudal, and mediolateral-oblique projection. At the time of the mammographic examination, 87 (51%) cancers were From the Iris Cantor Center for , Department of nonpalpable and 85 (49%) were palpable. Radiological Sciences, UCLA School of Medicine; the Jonsson All three mammographic projections were performed Comprehensive Cancer Center at UCLA, Los Angeles, Califor- with the patient standing and the breast distracted as nia. Presented at the 93rd Annual Convention and Scientific Assembly of the National Medical Association, Los Angeles, much as possible from the chest wall. The lateral view of California, August 1, 1988. Requests for reprints should be the breast was obtained with the x-ray beam directed addressed to Dr. Lawrence W. Bassett, Department of Radi- from medial to lateral positions, with compression ological Sciences, UCLA School of Medicine and The Jonsson Cancer Center, 10833 Le Conte Avenue, Los Angeles, CA applied in a true lateral plane (Figure A). The cepha- 90024-1721. locaudal view was obtained with the x-ray beam directed

JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 81, NO. 4 391 FILM-SCREEN MAMMOGRAPHY

Figure. The position of the standing patient in relation to the x-ray tube and compression device is shown. A. Mediolateral projection. B. Cephalocaudal projection. C. Mediolateral- oblique projection. (Reproduced with permis- sion from: Bassett LW, Gold RH: Breast radiog- raphy using the oblique projection. Radiology 1983; 149:585-587.)

mograms prior to surgery had 172 biopsy-proven carci- nomas. Eighty-seven (5 1%) of these were mammograph- ically detected nonpalpable tumors. With knowledge of the clinical findings and biopsy results, three of the authors reviewed the mammograms on all of these patients to determine what views showed the abnor- malities. RESULTS 90° from the lateral position, with compression applied Of the 172 cancers, a mammographic mass was pres- parallel to the floor and the nipple positioned in the ent in 113, calcifications alone in 38, and only distortion center of the image (Figure B). The oblique view was or asymmetry of the breast parenchyma in 12. Ninety- obtained with the x-ray beam directed perpendicular to five tumors were in the upper-outer quadrant, 26 in the the muscle in a superomedial-to-inferolateral direction, upper-inner, 18 in the lower-outer, 19 in the lower-inner, with compression applied parallel to the sagittal plane of and 14 were subareolar. the most superolateral part of the underlying pectoralis One hundred twenty-five of the cancers could be major muscle (Figure C). identified on all three mammographic views, 11 only on A review of surgical pathology reports disclosed that the oblique, 4 only on the mediolateral, 3 only on the during this time 169 patients who received mam- cephalocaudal. Ten cancers were not visible on any

392 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 81, NO. 4 FILM-SCREEN MAMMOGRAPHY mammographic projection. The remainder were de- projection, yet be visible in another.7'3 In this study, picted on various combinations of the three views. even the oblique projection-the most effective single Of the 11 cancers seen only on the oblique view, 10 view-failed to detect 15 cancers that were visualized on were in the upper-outer quadrant and I was in the upper- one or more other views, indicating that no single view is inner quadrant. Of 4 cancers seen only on the medi- perfect for breast cancer detection. olateral view, 2 were in the lower-inner quadrant, 1 was in The two-view oblique-cephalocaudal combination the upper-outer quadrant, and 1 was subareolar. Of 3 depicted 7 more cancers than a mediolateral-cepha- cancers seen only in the cephalocaudal view, 2 were in locaudal combination. Because two views at right angles the upper-outer quadrant and I was subareolar. to each other are necessary for localization of a lesion in Twenty-five cancers were not visualized on the three dimensions, a direct lateral image should be oblique projections, although 15 of these were seen on obtained whenever a suspicious lesion is identified in other projections, 26 were not visualized on the medi- oblique and cephalocaudal images. olateral projection, and 33 were not seen on the cepha- Single-view examinations result in more false- locaudal projection. positive interpretations and greater diagnostic indeci- A two-view mediolateral-oblique/cephalocaudal sion. 4"15 Patients are more likely to be asked to return combination depicted 158 (91.9%) of the cancers; a for additional views after single-view mammography, mediolateral-cephalocaudal combination depicted 151 ultimately resulting in higher overall costs for perform- (87.8%). ing the examination and considerable undue anxiety and inconvenience for patients. As radiation doses from DISCUSSION mammography have decreased, the risk of radiation- The optimal mammographic examination provides induced cancer from a two-view examination has the greatest information with the least radiation. Film- become negligible.'6 Moreover, the second view does screen mammography usually requires less radiation not significantly increase the time required to perform than xeromammography.4 Published reports have rec- the examination or its cost. 14 ommended use of the mediolateral-oblique projection as To summarize, the most effective single view for one of the projections for film-screen mammography68; film-screen mammography is the mediolateral-oblique. and this projection, already widely used in Europe, is Two views of each breast, oblique and cephalocaudal, gaining in popularity in the United States. Our study are recommended to improve sensitivity and specificity. confirmed that the mediolateral-oblique projection is the most diagnostically efficient of the mammographic Literature Cited views. 1. Silberberg E, Lubera J: Cancer statistics, 1987. CA 1987; The success of the oblique view in this study is 37:2-19. attributed to improved depiction of the deeper structures 2. Shapiro S: Evidence on screening for breast cancerfrom a in the upper-outer quadrant and axillary tail. In a large randomized trial. Cancer 1977; 39:2772-2782. 3. Tabar L, Fagerberg CJ, Gad A, et al: Reduction in mortality series reported by Haagensen,9 38.5% of breast cancers from breast cancer after mass screening with mammography. were found in the upper-outer quadrant, and Truscott"' Randomized trial from the Breast Cancer Screening Group of the that 4% of cancers in his series were in the Swedish National Board of Health and Welfare. Lancet 1985; reported 1:829-832. axillary tail. The ability of the oblique view to disclose 4. National Council on Radiation Protection and Measure- the deepest breast tissues depends on careful patient ments: Mammography-A User's Guide (NCRP Report, no. 85). and state-of-the-art mammographic Bethesda, Md, 1986. positioning requires 5. Bassett LW, Diamond JJ, Gold RH, et al: Survey of mam- equipment and an experienced technologist. The breast mography practices. AJR 1987; 149:1149-1152. should be pulled directly away from the pectoralis major 6. Lundgren B: The oblique view at mammography. Br J muscle while vigorous compression is applied. Because Radiol 1977; 50:626-628. 7. Andersson I, Hildell J, Mulow A, et al: Number of projec- a large portion of the axilla is routinely depicted on the tions in mammography: Influence on detection of breast disease. axillary view, special views of the axilla are not required. AJR 1978; 130:349-351. screening has been suggested as a 8. Bassett LW, Gold RH: Breast radiography using the Single-view oblique projection. Radiology 1983; 149:585-587. method to reduce radiation exposure, cost, and examina- 9. Haagensen CD: Diseases of the Breast, ed 2. Phila- tion time. "'.12 However, this method has two major delphia, WB Saunders Co, 1971, p 381. limitations: a breast cancer will be missed if the single 10. Truscott BM: Carcinoma of the breast. Analysis of symp- toms, factors affecting prognosis, results of treatment and recur- view does not include the involved area; and a cancer rences in 1211 cases treated at Middlesex Hospital. BrJ Cancer may be obscured by overlying parenchymal tissue in one 1947; 1:129-145.

JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 81, NO. 4 393 FILM-SCREEN MAMMOGRAPHY

11. Lundgren B, Jakobsson S: Single view mammography. A 14. Sickles EA, Weber WN, Galvin HB, et al: Baseline screen- simple and efficient approach to breast cancer screening. Can- ing mammography: One vs two views per breast. AJR 1986; cer 1976; 38:1124-1129. 147:1149-1153. 12. Buchanan JB, Jager RM: Single view negative mode 15. Bassett LW, Bunnell DH, Jahanshahi R, et al: Breast can- xeromammography: An approach to reduce radiation exposure cer detection: One versus two views. Radiology 1987; in breast cancer screening. Radiology 1977; 123:63-68. 165:95-97. 13. Hall FW, Berenberg AL: Selective use of the oblique pro- 16. Feig SA: Radiation risk for mammography: Is it clinically jection in mammography. AJR 1978; 131:465-468. significant? AJR 1984; 143:460-475.

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