Role of X-Ray Mammography in the Detection of Breast Cancer: Facts vs. Fiction

Over the years there has been much confusion in the news media and general population as to the exact indications and utility of X-Ray mammography (XMM) in the detection of breast cancer. The American College of Radiology
(ACR) has developed Standards for the Performance of and the Indications for the use of Screening Mammography, which are very specific. Here in this article I shall attempt to shed some light on the past confusion on the indications and usage of mammography.

FDA and ACR formulated strict standardization of mammography through out the nation (USA) since at that time mammography was the only X-Ray modality to screen cancer breast. Because of the standardization, all mammographic units must meet certain quality in their images. This has eliminated the facilities which perform low quality images on substandard or old machines.

The current Mammographic guidelines established by ACR and American Cancer Society are as follows:

o ALL women by the age of 40 should have a single screening mammogram;
o Women between 40-49 years should have mammography performed at an intervals of ONE to TWO years;
o Women of 50 years of age and/or older should have screening mammogram annually when feasible.

XMM is the most accurate X-Ray modality (non-invasive) available at present for detecting carcinoma breast, although it has some limitations. Several studies have shown that approximately 10% of CA breast (breast cancer) will not be seen by mammography regardless of the quality of he instrument and experience of the radiologist. Hence a mammogram is not a perfect, full proof test for screening breast CA.

For this reason, Self Breast Examination (SBE) is still very important to the patient as an adjunct to XMM. If there is a palpable mass in the breast on SBE or indeterminate breast lesion in XMM, an excision biopsy or FNAC should not be delayed especially when the physician suspects the mass to be malignant. Women under 40 years of age frequently have very dense stromal tissue within the breasts that tends to obscure occult tumours on XMM. It is for this reason that routine mammography is not recommended for women under 40 years of age. Exceptions to this rule are – firstly, under 40 years women having clearly palpable lesion suggesting malignancy, and secondly, young women with high risk of breast cancer such as strong family history of breast malignancy.

Periodic mammographic screening of asymptomatic women has shown to reduce breast CA mortality considerably by detecting the malignancy at a far earlier stage than previously possible.

Despite this advantage and guideline, many women are reluctant to undergo XMM. Major reasons have been – Cost of the test and fear of Radiation toxicity, particularly any risk of increased malignancy if present.
To address the second point, it is to be noted that average glandular radiation dose to the breast from a 2-view XMM is negligible, particularly in women over 40 years age and should not be a factor in prescribing a mammogram.

Summary:

Considering the high sensitivity and specificity of XMM in elder women >40 years, X-ray Mammography has become a routine part of managed care as earlier detection of CA breast reduces the mortality, significantly reduces the cost, social burden over economy and improve the quality of life. However it is imperative to remember that Self Breast Examination (SBE) and physical examination by an experienced physician of any palpable mass in breast and axillary lymph nodes status plays both a necessary and complimentary role in the early detection and treatment of breast cancer.