Breast cancer relapse higher in dense breasts

According to researchers, those with dense breasts are more than four times likely to see their cancer recur as opposed to the women with less dense tissues.

Dr. Steven Narod of the Women’s College Hospital in Toronto, who led the study stated, “The composition of the breast tissue surrounding the breast cancer is important in predicting whether or not a breast cancer will return after surgery.”

The researchers reviewed the medical records of 335 women who underwent lumpectomy for invasive breast cancer. With the help of pre-treatment mammogram for assessment of breast density they were monitored for recurrence risk.

The breasts of the patient’s were categorized as low density (less than 25 percent dense tissue present), intermediate (25 to 50 percent), and high (more than 50 percent).

Risk of relapse higher in dense breast tissue
The researchers took into account factors like age, menopausal status, and use of radiotherapy. They noted that over a decade, women in the high density group had a 21 percent chance of a relapse as compared with a 5 percent chance in women with less dense breasts.

The investigators also found that the recurrence rate at ten years was more pronounced in women who did not receive radiation after surgery for invasive breast cancer.

In addition, the rate of the disease returning was 40 percent higher in women with dense breast tissues who had not undergone radiation, while there was no relapse in patients with low density breasts.

"We believe these data confirm the benefit of radiotherapy in women with dense breasts," the researchers wrote.

A word of caution
Though the study indicates that the density of a woman’s breast can influence the chance of her developing cancer, the doctors state that "the biological basis of the association with cancer risk is largely unknown."

They also caution that dense tissues in the breast can have a concealing outcome, which can reduce the sensitivity of a mammogram.

Study vital for future treatment
Maria Leadbeater, clinical nurse specialist with Breast Cancer Care, said, “This small study provides a unique retrospective insight into the link between breast density and risk of recurrence after breast conserving surgery.

“By being able to determine which women may or may not benefit from radiotherapy it may be possible to offer more tailored treatment, as well as reducing the total number of women having radiotherapy, which can have significant long-term side effects.”

The findings were published in the journal Cancer.