New Triple-Negative Breast Cancer Develops During Olaparib Treatment for a Separate Lung Cancer

What happened, in summary

While receiving olaparib for a separate metastatic lung adenocarcinoma, a 65-year-old woman developed a new lesion in her right breast in February 2023. Biopsy showed a triple-negative invasive breast adenocarcinoma. She underwent quadrantectomy, and the removed tumor measured 14 mm.

Molecular testing found a second BRCA2 change that restored the gene’s reading frame, known as a reversion mutation. The authors considered this important because the new breast tumor had developed despite ongoing olaparib treatment and appeared to represent a separate primary cancer rather than progression of the lung cancer.

She received adjuvant radiation to the right breast. Additional breast-cancer chemotherapy was not given because her clinicians wanted to avoid disrupting olaparib, which was continuing to control the metastatic lung cancer. Keeping the two cancers separate is important in this case: olaparib was continued for the lung cancer, while surgery and radiation were used to manage the new triple-negative breast primary.