Local DCIS recurrence low in post-menopausal, ER+ women
Post-menopausal women diagnosed with oestrogen receptor (ER)-positive ductal carcinoma in situ (DCIS) who undergo breast-conserving surgery followed by whole breast radiotherapy have a reduced risk of developing local recurrence, according to a study from Italy.
Researchers of this multicentre (nine centres in Italy), retrospective study examined data of 1,072 patients with DCIS who had undergone treatment with breast-conserving surgery and adjuvant whole breast radiation with or without endocrine therapy between 1997 and 2012. Of these, 51.9 percent (n=557) were ER-positive, 50.1 percent (n=279) of whom were administered adjuvant endocrine therapy.
Patients were followed up for a mean 8.4 years, at which point, there were 67 incidences of local recurrence (25 and 42 with DCIS local recurrence and invasive local recurrence, respectively) and 47 deaths (11 related to breast cancer). The mean time to local recurrence was 5.4 and 8 years for DCIS and invasive local recurrence, respectively.
Overall, rates of local recurrence were low, standing at 3.4 percent at 5 years and 7.6 percent at 10 years. Overall survival and breast cancer specific survival rates were high at 5 years (98.5 and 99.7 percent, respectively) and 10 years (97 and 99.1 percent, respectively).
Multivariate analysis showed that women who were post-menopausal at time of initial DCIS diagnosis had a lower risk of local recurrence compared with pre-menopausal women (hazard ratio [HR], 0.40, 95 percent confidence interval [CI], 0.18–0.92; p=0.03). [EBCC 2018, abstract 215]
The risk of local recurrence was also lower among women with ER-positive cancers (HR, 0.35, 95 percent CI, 0.13–0.98; p=0.045).
Conversely, having a smaller final surgical margin (<1 mm) raised the risk of local recurrence (HR, 3.3, 95 percent CI, 1.17–9.28; p=0.024).
Among ER-positive patients, adjuvant endocrine therapy did not appear to affect the risk of local recurrence (p=0.34), be it DCIS local recurrence (p=0.92) or invasive local recurrence (p=0.25), or overall survival (p=0.81).
“The results of this study should offer all DCIS patients reassurance that the risk of their cancer returning is very low, if they are treated with breast conserving surgery followed by radiotherapy. For patients who are post-menopausal or whose cancer is ER-positive, the likelihood of recurrence is even lower. Where the results of surgery reveal very small cancer-free margins, the risk of recurrence is higher,” said study lead investigator Dr Icro Meattini from the University Hospital of Florence, Italy, when presenting the results at EBCC 2018
“Although we know that very few patients [with DCIS] will go on to develop invasive cancer, we don’t know which ones they will be and so we offer treatments such as surgery and radiotherapy, and sometimes hormone therapy,” he said, calling for research into identifying if less or no treatment would suffice in patients with a lower risk profile, as well as treatments that would be most beneficial for high risk patients.
At present, treatments should be tailored to each patient’s cancer and circumstances, he concluded.