Breast Cancer Screening During Lactation

It happened again last spring. At the edge of a sunny peaceful pond, as my friend and I watched our children splashing in the water and pursuing tadpoles, she quietly shared with me the news that her friend had recently been diagnosed with breast cancer. Another young mother with breast cancer. It's an uncomfortable reminder that I am now undeniably in the age group where breast cancer starts to 'happen'. The news made me a little more nervous than usual, since I was only weeks away from turning the age my mother was when she was diagnosed with terminal breast cancer. Even more distressing, I was well aware that I was already five years 'overdue' for a mammogram.

The National Cancer Institute, the American Cancer Society, and the American College of Radiology all recommend annual screening mammograms for women beginning at age 40. While to date there have been no studies conclusively demonstrating that mammograms given to women before the age of 40 reduce the risk of death from breast cancer, many doctors recommend that women have a 'baseline' mammogram between the ages of 35 and 39 (Medicare and most insurance companies will pay for it).¹ Furthermore, if a woman is at high risk for breast cancer (see box), she is encouraged to discuss with her physician the benefits and limitations of even earlier mammogram screening.^2,3

I am considered to be at high risk for contracting breast cancer since my mother was diagnosed with premenopausal breast cancer at age 37, my first cousin on my mother's side was diagnosed with breast cancer in his 30's, and my maternal aunt recently had ovarian cancer. Health care professionals have repeatedly told me that because of my high-risk status, I should have a baseline mammogram approximately five years before the age my mother was when she was diagnosed. For me, that would have been in the year 2000, when I was 32.

On the other hand, the same health care professionals also told me that I cannot have a mammogram if I am breastfeeding. It's not that mammography is hazardous to the breastmilk or the nursling; the x-ray radiation used in mammograms does not stay in the tissues so it does not affect the milk or the baby.⁴ The reason mammograms are contraindicated for a lactating breast, I was told, is for the same reason mammograms are less effective in younger women: Both lactating breasts and young breasts tend to be very dense. This makes the resulting mammogram more difficult to read, and may lead to a higher rate of false negatives (the mammogram appears normal even though breast cancer is actually present). For this reason, at each of my annual clinical breast exams, my certified nurse midwives told me to wait six months after weaning before having a mammogram. One midwife told me she was even sent away from a mammogram clinic when she arrived only five months post-weaning, so I really had to wait the FULL six months.

Well, I have been either pregnant or lactating for the past seven years, with no end in sight. The time when I would have ordinarily been sent in for a mammogram came and went, and since I was apparently 'ineligible' for a mammogram, I did not have one.

Average maternal age is increasing, as more and more women are having babies in their late 30's and early 40's. Furthermore, advancements in the study of breast cancer are making it easier to determine whether an individual is at high risk for developing the disease. At the same time, public health organizations are encouraging mothers to breastfeed for a minimum of one year. Consequently, I suspect I am not the only woman who has encountered an apparent timing conflict between breastfeeding and recommended mammography screening.

Despite never having had a mammogram, I have taken some comfort from the many studies which have demonstrated that breastfeeding itself actually reduces a woman's relative risk for contracting breast cancer,^5,6,7 and confers protective benefits on her nursling as well.⁸ A woman who breastfeeds for 24 months of her life has only half the risk of developing breast cancer as a woman who breastfeeds for between one and six months.⁷ While added protection from breast cancer is not one of the primary reasons I practice sustained breastfeeding, it is a nice advantage. But the benefit is not something any individual can count on.

When I spoke to a nurse at the breast health center of my local hospital about the possibility of having a mammogram while lactating, she told me that a mammogram of someone in my situation would be 'only about 45% effective' so it wasn't worth having one until after weaning. She delicately suggested that I decide for myself which were more important 'g nursing my child or 'having a mammogram you can trust.'

I have since learned that my decision to delay screening mammography in favor of allowing my child to wean at his own pace was a false choice. Breastfeeding and meaningful mammography are not necessarily mutually exclusive.