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Nigerian Journal of Surgical Research
Surgical Sciences Research Society, Zaria and Association of Surgeons of Nigeria
ISSN: 1595-1103
Vol. 6, Num. 1-2, 2004, pp. 73-75

Nigerian Journal of Surgical Research, Vol. 6, No. 1-2, Jan-June, 2004, pp. 73-75

Letter to the Editor

Current views on breast cancer imaging

A. A. Bajomo

Department of Radiology, Olabisi Onabanjo University Teaching Hospital, Sagamu, P. O. Box 2108, Dugbe, Ibadan. E-mail: bayobajomo@yahoo.com

Code Number: sr04024

Breast cancer is a common and deadly disease that metastasizes early in its natural history and may recurlater. ¹ It shows an incidence that increases with age. The disease is extremely rare in males, accounting for approximate 0.7% of all cases. ² Multidisciplinary teams that compromise breast surgeons, radiologists, pathologists and oncologists, should provide appropriate breast cancer management. ¹ Radiological imaging methods available for the diagnostic work-up of breast cancer include mammography, breast ultrasound and magnetic resonance imaging.

Mammography (MMG)
It was recognized more than 60 years ago that clinically occult breast cancer could be visualized on radiography. ³ Technical developments in film-screen MMG coupled with evidence suggesting that MMG screening resulted in a reduction on breast cancer mortality^{4, 5} led to the introduction and wide acceptance of screening MMG in several western countries by the 80s. Screening MMG aims to diagnose breast cancer early and is advocated in women above 50. The accuracy and positive predictive value of MMG are higher in older than in younger women. ⁶ This may be related to the higher frequency of the disease and the reduced breast density on MMG seen with increasing age. There is no agreement on the case for breast cancer screening in women aged <50 as higher false positive rate in younger women⁶ often leads to unnecessary patient anxiety.

More cases of ductal carcinoma in-situ (DCIS) are being diagnosed with improved MMG technology especially in younger women. ⁷ and currently there is concern that these lesions are being treated too aggressively as more than half may never become invasive or metastasise. Results, in late 2004, are expected to show whether digital MMG is as sensitive, specific and more cost effective than film MMG, and whether it will be able to obviate unnecessary biopsies. ^{9, 10}

Breast ultrasound (USS)
The accepted role of ultrasound is as an adjunct to mammography, and it has been advocated as a tailored examination to assess an area of mammographic and/or palpable abnormality rather than as a complete survey of the breasts. ¹ It has a poor spatial resolution in that microcalcifications in tumours are poorly detected. However, whole breast USS has been recently shown to be of value in the detection of multicentric and multifocal cancer when used pre-operatively in situations where breast conservation surgery is contemplated. ¹² USS is the initial method of choice in younger women with breast symptoms because it does not involve radiation. It is 96-100% accurate in the diagnosis of cysts, which constitute some 25% of all palpable or mammographically detectable lesions. ¹³ However, current USS equipment is also able to detect malignant microcalcifications ¹⁴ and is able to show axillary nodal involvement. Breast USS is increasingly sued in image-guided breast procedures such as tine needle aspiration cytology, biopsies and hook-wire localization of lesions prior to surgical excision.

Magnetic resonance imaging (MRI)
The ability of contrast enhanced MRI to demonstrate breast cancer was first reported by Hewang et al. ¹⁵ Most authors subsequently report high sensitivity exceeding 98% in breast cancer detection using contrast MRI, with much lower specificity because some design lesions also enhance. ¹⁶

There are controversial issues regarding the benefits derived from mammography, while exciting developments in Breast MRI promise more accurate imaging in staging breast cancer and monitoring treatment response.

A. A. Bajomo

Department of Radiology, Olabisi Onabanjo University Teaching Hospital, Sagamu, P. O. Box 2108, Dugbe, Ibadan. E-mail: bayobajomo@yahoo.com

REFERENCES

Forrest APM. Breast cancer 100 years on – what we have learnt. Med J Malaysia 1996; 51: 767-773.
Wilhelm MC, Wanebo HJ. Cancer of the male breast. Comprehensive management of benign and malignant diseases. In: Bland KI, Copeland M (eds). Saunders, Philadelphia. 1991; 1030-1033.
Gershon – Cohon J, Strickler A. Roentgenological examination of the normal breast; its value in demonstrating early neoplastic change. AJR 1939; 40: 189-201.
Nystrom L et al. Breast cancer screening with 2 mammography. Lancet 1993; 341: 973-978.
Tabar L, Gad A. Reduction in mortality from breast cancer after mass screening with mammography. Lancet 1985; 82:32.
Fletcher SW. Why question screening mammography for women in their forties. Radiol Clin Nor Am 1995; 33: 1259-1271.
Kerlikowske K. Positive predictive value of screening mammography by age and family history of breast cancer. JAMA 1993; 270: 2444-2450.
Gorman C. Rethinking breast cancer. Time 2002; 159: 30-38.
RSNA News. ‘Diagnosing’ the effectiveness of digital mammography, 2002; 12(r): 8-9.
Pisano ED. The American College of Radiology Imaging Network’s Digital Mammography Screening Trial. J Women’s Imaging 2001; 3: 58-59.
Jackson VP. The current role of ultrasonography in breast imaging. Radiol Clin Nor Am 1995; 33: 1161-1170.
Berg WA, Gilbreath PL. Multicentric and multifocal cancer: whole breast US in preoperative evaluation. Radiology 2000; 214: 59-66.
Dennis MA, Marker SH. Breast biopsy avoidance. The value of normal mammograms and normal sonograms in the setting of a palpable lump. Radiology 2001; 329:186-191.
Starros AT. Solid breast nodulesi. Use of sonography to distinguish between benign and malignant lesion. Radiology 1995; 1961:123-134.
Heywang SH. MR imaging of the breast using gadolinium – DPTA. J Cat 1986; 10:199-204.
Viehwg P. Contrast-enhanced magnetic resonance imaging of the breast. Top MRI 1998; 9: 17-43.