Researchers identify factors associated with lower breast cancer recurrence risk

Issue: May 10, 2018

Postmenopausal women and those with ER-positive tumors appeared less likely to experience ductal carcinoma in situ recurrence, according to results of a retrospective analysis presented at the European Breast Cancer Conference.

“A diagnosis of DCIS can be frightening but also confusing. Although we know that very few patients 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,” Icro Meattini, MD, clinical oncologist in the radiation oncology unit at University of Florence in Italy, said in a press release. “We wanted to look in detail at women treated for DCIS to see if there are any clues about who is most at risk of a recurrence, and to understand the risks and benefits of different treatments.”

DCIS comprises 20% of breast cancer cases. Despite limited research on which cases will progress, DCIS is treated similarly to other types of breast cancer. Breast-conserving surgery and whole-breast radiation with or without endocrine therapy is standard treatment for DCIS; however, appropriate treatment following surgery has remained controversial.

Meattini and colleagues conducted an analysis of 1,072 patients with DCIS treated at one of nine clinical centers in Italy between 1997 and 2012. Each patient had undergone breast-conserving surgery and adjuvant radiotherapy. Among the patients, 51.9% had positive hormonal status. Of these, 50.1% received adjuvant endocrine therapy.

Researchers compared 5- and 10-year local recurrence rates, OS and breast cancer-specific survival.

The mean follow-up was 8.4 years (range, 4-20).

Of 47 deaths, 11 were related to breast cancer, according to the researchers.

Local tumor recurrence events occurred among 67 patients — 42 were invasive and 25 in situ. The overall mean time to local recurrence was 7 years. Mean time to local recurrence was 5.4 years for in situ and 8 years for invasive.

Local recurrence rates were 3.4% (95% CI, 2.3-4.5) at 5 years and 7.6% (95% CI, 6-9.2) at 10 years.

OS rates were 98.5% at 5 years and 97% at 10 years. The breast cancer-specific survival rates were 99.7% at 5 years and 99.1% at 10 years.

Univariate analysis showed postmenopausal status (HR = 0.52; 95% CI, 0.32-0.85), ER positivity (HR = 0.32; 95% CI, 0.17-0.60), PR positivity (HR = 0.46; 95% CI, 0.25-0.88) and endocrine therapy (HR = 0.39; 95% CI, 0.20-0.77) inversely correlated with local recurrence.

“The results of this study should offer all [patients with] DCIS reassurance that the risk [for] their cancer returning is very low if they are treated with breast-conserving surgery followed by radiotherapy,” Meattini said.

Conversely, final surgical margins smaller than 1 mm strongly correlated with higher local recurrence rates (HR = 3.25; 95% CI, 1.49-7.08).

Multivariate analysis confirmed favorable effects from postmenopausal status (HR = 0.4; 95% CI, 0.18-0.92) and ER positivity (HR = 0.35; 95% CI, 0.13-0.98) on local recurrence, whereas final surgical margins smaller than 1 mm confirmed a negative effect (HR = 3.3; 95% CI, 1.17-9.28).

Among patients with positive hormonal status, adjuvant endocrine therapy showed no significant effect on overall local recurrence, DCIS recurrence, invasive local recurrence and OS.

“Now we need to do more research to find out if lower-risk patients can safely be given less treatment or even no treatment, as well as studies on how best to treat higher-risk patients,” Meattini said in the release. “In the meantime, it’s vital that each patient receives treatment that is best suited to their individual cancer and their particular circumstances.” – by Melinda Stevens

Reference:

Meattini I, et al. Abstract 215. Presented at: European Breast Cancer Conference; March 18-20, 2018; Barcelona, Spain.

Disclosures: The authors report no relevant financial disclosures.