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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Friday, April 29, 2022
Research presented at the American Association for Cancer Research (AACR) Annual Meeting 2022 (Abstract 43/4) suggests that some patients with recurrent ductal carcinoma in situ breast cancer may, in fact, be developing new primary tumors—and thus perhaps may require different treatment. The study, conducted by Tanjina Kader, PhD, of the Peter MacCallum Cancer Centre, Melbourne, Australia, and colleagues, originally sought to determine whether a biomarker might be identified to aid in predicting which ductal carcinoma in situ cases may recur.
“These findings can influence how patients are managed in the clinic,” noted Dr. Kader in an AACR press release. “For example, the occurrence of a new primary lesion in the same patient suggests a high-risk breast environment in which new tumors may develop over the years. Therefore, such patients would be candidates for preventive breast removal surgery, even if the tumor is small, and they might be referred to genetic testing to ascertain whether they have any genetic predisposition.”
In the study, DNA was extracted from 65 pairs of primary ductal carcinoma in situ tumors and recurrences. Of the included recurrences, half were invasive breast cancer. Targeted sequencing or low-coverage whole-genome sequencing was used to analyze 21 pairs, and 44 pairs were analyzed via whole-exome sequencing. A set of 29 nonrecurrent ductal carcinoma in situ samples were also evaluated at a minimum follow-up of 7 years.
Of the pairs, 52% were clonal and 28% were nonclonal. A total of seven equivocal cases were identified. Although invasive recurrent cases demonstrated a substantially higher ploidy than did ductal carcinoma in situ cases, no meaningful difference in clonal relatedness was noted between the two. A relationship was observed between clonal primary ductal carcinoma in situ and TP53 mutations as well as overall copy number events. Given the frequency of clonally unrelated recurrences, a biomarker may not be a reliable predictive tool, the study authors noted.
Disclosure: For full disclosures of the study authors, visit abstractsonline.com.
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