The most common treatment for ductal carcinoma in situ (DCIS) is breast-conserving surgery (BCS) and while the procedure has been shown to be effective at reducing cancer mortality, women undergoing BCS should be prepared for the possibility of future diagnostic mammograms and invasive breast procedures for as long as 10 years after surgery, according to research published online April 5 in the Journal of the National Cancer Institute.
“Breast-conserving treatment is a reasonable option for women with DCIS and results in similar long-term mortality outcomes as mastectomy; however, invasive procedures and diagnostic evaluation workup for possible recurrent breast cancer extends over a long period following DCIS excision and treatment,” wrote authors Larissa Nekhlyudov, MD, MPH, of Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston, and colleagues.
The authors noted that previous studies had identified a risk of re-excisions following an initial BCS, but there hadn’t been any studies examining the rate of diagnostic evaluations for recurrent breast cancer in patients after undergoing BCS. To shed some light on this question, they identified 2,948 women with DCIS who were treated with BCS from 1990 to 2001 and tracked their subsequent care over the following 10 years, calculating the percentages of diagnostic mammograms and ipsilateral invasive procedures.
The authors estimated that three quarters of the women were at risk for at least one diagnostic procedure over the 10 years following BCS. Specifically, results showed 30.8 percent of the women in the study had a diagnostic mammogram and 61.5 percent had an invasive procedure in the ipsilateral breast.
Just over half of the women had an ipsilateral invasive procedure, usually a re-excision, in the first six months after BCS, so the researchers also estimated the cumulative incidence of diagnostic procedures starting after this point. Using the six month and later criteria, corresponding risks were 36.4 percent for diagnostic mammograms, 30.4 percent for invasive procedures and 49.5 percent for either.
“Re-excisions to obtain clear margins present a unique burden to women undergoing BCS because women who initially choose to undergo mastectomy following diagnosis are not usually subject to these repeat procedures,” wrote the authors.
Nekhlyudov and colleagues offered a few explanations for the increased rates of diagnostic imaging and invasive procedures. Women may be more concerned about recurrence and have high levels of anxiety about their diagnosis, making them more vigilant about new symptoms. Their doctors also may be more attentive of abnormalities in patients who would have a higher risk of recurrence, which could result in more diagnostic testing.
While BCS is the most common treatment for women with DCIS, the authors noted that mastectomy rates have again begun to increase and that women’s preferences may be one of the drivers of this shift in trends. Research has shown that after women were informed of the risks of mortality, treatment and recurrences after BCS and mastectomy, 35 percent chose mastectomy.
Nekhlyudov et al said their study, although not addressing the benefits and harms of mastectomy versus BCS, does offer some insight into the expected frequency of diagnostic imaging and invasive procedures that could play into DCIS treatment decisions. “The fact that women undergoing BCS are likely to have diagnostic and invasive breast procedures in the conserved breast over an extended period of time is important and needs to be included in discussions about treatment options.”