It is difficult to get image of breast abnormality or tumour in case of dense breasts in mammography, where a cancer may not be detected at an early stage; consequently giving rise to possibility of cancer spreading to distant places.
It is mandatory in US to inform the patient of the density of her breast tissue. Now, a new legislation is going to be framed by which it will be essential to inform the patient that the radiation dose from mammography may cause new cancer.
The laws owe their existence mostly to Nancy M. Cappello, 59, of Woodbury, Conn. She was not told that she had dense breast tissue until after doctors found an advanced cancer that mammograms had missed. She took her story to legislators, and in 2009, Connecticut became the first state to require that women be told if they have dense breasts and that insurance companies cover ultrasound scans for those women.
Ms. Cappello, the woman who started the movement to inform patients, began having yearly mammograms at age 40. In 2004, when she was 51, her doctor felt a lump in her breast — only six weeks after a mammogram had looked normal. Even after the lump was detected, mammography still could not find it. Only then was Ms. Cappello told that she had dense breast tissue. The cancer had already spread to 13 lymph nodes. She needed a mastectomy, chemotherapy, radiation and hormone treatment.
Breast consists of glandular, fibrous and fatty tissue apart from other tissue in small proportions. “Dense” breasts have a relatively high proportion of glandular or connective tissue, which blocks X-rays. Non-dense breasts have more fat, which X-rays penetrate easily.
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| Left~Dense Breast, Right~Non-dense with Abnormality |
Over all, about 40 percent of women who have mammograms have dense breast tissue. Younger women are more likely to have dense tissue, but as many as 25 percent of older women do, too. Density cannot be judged by touch; it shows up only on mammograms.
The National Cancer Institute calls dense breasts “a strong risk factor for developing breast cancer.” Various studies have estimated that compared with other women, those with dense breasts are two to six times as likely to develop breast cancer. The reason is not known. But dense breasts have more milk ducts and lobes, where most cancers form, so some researchers think the added risk may come from having more of that tissue.
On mammograms, dense breasts look white, and so does cancer, so the tissue can hide tumors. Fatty breasts show up mostly black, so tumors stand out.
Studies have found that when women with dense breasts were given mammograms and then ultrasounds, the ultrasound found tumors that the mammograms missed — but also produced many false positives that led to biopsies.
Studies of women with dense breasts that were published in June in the journal Radiology and in April in The Journal of the American Medical Association found that for every 1,000 women screened, adding ultrasound found three to five cancers that mammograms missed. But in one study, 63 biopsies or other invasive procedures were performed to find three tumors.
M.R.I. exams can also find tumors that mammograms miss, but they produce even more false positives.
Despite its shortcomings, mammography does find some tumors in women with dense breasts — including some that ultrasound misses — so doctors emphasize that these women should not skip mammograms.
So, it is advisable to have ultrasound of breast, if mammogram labels the breast to be dense. Recently, it has been recommended to have ultrasound in females below 40 years of age. As a supportive diagnostic tool in case of families of breast cancer, where there is still suspicion MRI can be performed. All the imaging results may be studied together to arrive at a conclusion.
The ladies subjected to mammography should always read their report for the possibility of having dense breasts reported according to the American College of Radiologists (ACR).
