Studies show that if left untreated, between 20% and 40% of ductal carcinoma in situ (DCIS) lesions may evolve into invasive breast cancer over time. And, according to the American Cancer Society, women diagnosed with lobular carcinoma in situ (LCIS) have between a 7 and 12 times higher risk of developing invasive cancer in either breast over time.
A retrospective study evaluating whether the 313-SNP breast cancer polygenic risk score (PRS313) can predict the likelihood of developing ipsilateral or contralateral breast cancer after a diagnosis of DCIS or LCIS has found that patients with a high PRS313 score were more likely to develop breast cancer in the contralateral breast compared with patients with a low PRS313 score. The test has the potential to guide clinical decisions about surveillance, risk-reduction treatments, and personalized care, which may improve outcomes, say the study authors, who published their findings in Cancer Epidemiology, Biomarkers & Prevention.
Study Methodology
The researchers used Cox regression to analyze data from patients diagnosed with DCIS (n = 2,169) or LCIS (n = 185) participating in the ICICLE and GLACIER studies, with a median of 11 years of follow-up. For patients with DCIS, the researchers stratified the PRS313 scores into quartiles and compared them with outcomes; for patients with LCIS, the researchers measured associations between increasing PRS313 scores and outcomes.
Outcomes included any further in situ or invasive breast cancer, including distant metastasis or ipsilateral, invasive ipsilateral, and/or contralateral breast disease.
Results
The researchers found a significant association between increasing continuous PRS313 and the risk of contralateral disease following a diagnosis of DCIS (hazard ratio [HR] = 1.30; 95% confidence interval [CI] = 1.08–1.56), and a link between PRS313 and ipsilateral disease after a diagnosis of LCIS (HR = 2.16; 95% CI = 1.22–3.81).
“This research provides strong evidence that PRS313 can serve as a valuable predictor of future breast cancer events in women with in situ breast cancer, specifically contralateral disease after DCIS and ipsilateral disease after LCIS,” concluded the study authors.
Understanding Treatment Options After a DCIS or LCIS Diagnosis
“LCIS is not always surgically removed or treated with hormone therapies, as it is considered lower risk than DCIS,” said lead study author Jasmine Timbres, Clinical Information Analyst at King’s College London. “However, these results indicate that those with a family history may benefit from such additional treatments, which could reduce their risk of further cancer.”
“The associations found in this study could be useful in helping women decide their treatment options after a diagnosis of DCIS or LCIS. By looking at the full picture rather than just how cells look under a microscope, we can give women more accurate information about their personal risk of recurrence. This could help them make more informed choices about their treatment options and what’s right for them,” she concluded.
Disclosure: Funding for this study was provided by Breast Cancer Now, Cancer Research UK, and the Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London. For full disclosures of the study authors, visit aacrjournals.org/cebp.
