Case Study: Metastatic Triple-Negative Breast Cancer

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In the final case study of the discussion, moderator Adam M. Brufsky, MD, PhD, describes a 58 year-old Caucasian woman with a 4 cm infiltrating ductal carcinoma in her right breast. Following a core biopsy, the primary tumor was found to be ER, PR, and HER2-negative by IHC and FISH. The patient received four cycles of adjuvant Adriamycin plus cyclophosphamide followed by 12 cycles of weekly paclitaxel.

After approximately 14 months, the patient developed shortness of breath and multiple bilateral pulmonary nodules were found by PET-CT scan, the largest of which was approximately 2 cm in diameter. One of these nodules was biopsied and revealed triple-negative histology consistent with the primary tumor, Brufsky notes.

This patient is at high-risk for brain metastases, believes Andrew D. Seidman, MD. At this point, regardless of symptoms, Seidman recommends conducting a brain MRI. Unfortunately, there is not a hard set standard of care for patients with triple-negative breast cancer (TNBC), although several agents are under investigation, including PARP inhibitors, platinum-based agents, and angiogenesis inhibitors. At this point, the patient may benefit from the re-administration of a taxane, believes Seidman.

Clinical data from the TBCRC009 trial provides support for the idea that patients with basal-like TNBC benefit from platinum-based treatment, believes Joyce A. O'Shaughnessy, MD. In this study, patients received single-agent cisplatin or carboplatin with a secondary mutational analysis looking at BRCA mutations. All patients on the trial were long-term survivors who had been off therapy until being treated in the first-line metastatic setting in the trial. In addition to these findings, O'Shaughnessy notes, observationally, a small group of patients with TNBC appear to experience long remissions when treated with platinum-based therapy.

A combination of gemcitabine and carboplatin is commonly utilized to treat TNBC but has yet to demonstrate superiority to other therapies in clinical trials, believes Seidman. Despite this, Rugo believes that patients are more likely to respond to the gemcitabine and carboplatin combination than a taxane. However, the TBCRC009 trial suggests that single-agent platinum-based therapy may be sufficient.