Initial Case Impressions and Treatment Options

Joyce O’Shaughnessy, MD:This patient is a 58-year-old woman who presented with stage II breast cancer that was estrogen receptor [ER]—positive and HER2-negative, with an intermediate recurrent score. She was treated with anastrozole [Arimidex] alone in the adjuvant setting. At the end of her 5 years of anastrozole, she was found to have liver metastasis. This is a bit of an unusual scenario for a woman with an invasive lobular cancer; it says to me that there must have been some component of more aggressive disease in there, such as a pleomorphic invasive lobular cancer. This probably explains, in my mind, why she developed the liver metastasis. But now she has metastatic breast cancer and is going to need a treatment option for her metastatic disease.

This 58-year-old woman presented with an invasive lobular cancer that was a T2N0 breast cancer, ER-negative, HER2-positive. I would have sent an Oncotype recurrent score for her as was done; it came back at 19. Fortunately, because of the TAILORx trial data, we have excellent high-level evidence that she will not benefit from chemotherapy. The postmenopausal women in the midrange recurrent scores really had no benefit at all from chemotherapy. We can sit down and say with a good degree of certainty that we would recommend antiestrogen therapy alone, and aromatase inhibitor would be ideal for her. I would also treat her with intravenous zoledronic acid every 6 months for 5 years per our new National Comprehensive Cancer Network [NCCN] Guidelines. We have very clear-cut evidence that she will not benefit from chemotherapy.

This case is unusual because the recurrent score was in the reassuring range; it was 19. And we would feel that the antiestrogen therapy, the anastrozole, would have a high degree of benefit for her, assuming she was adherent to the treatment. It’s a bit unusual to develop liver metastasis at the end of the aromatase inhibitor period of 5 years. She must have had an aggressive component in there, some pleomorphic invasive lobular cancer; certainly, it’s important to biopsy that disease and make sure that there wasn’t a subclone that was HER2-positive, for example. Assuming that the liver was biopsied and is the same breast cancer, estrogen receptor­—positive, HER2-negative, we then think about treatment options for her. It’s very clear to me that a CDK4/6 inhibitor with endocrine therapy would be the definite standard of care for her, and this is something that we would talk to her about. In the older years, we would have considered chemotherapy for metastatic breast cancer in the liver, and she is somewhat symptomatic with that. But now with the CDK4/6 inhibitors, we know that she’ll get superior outcomes with CDK4/6 inhibitor plus endocrine therapy compared with chemotherapy first line.

Transcript edited for clarity.

A 58-Year-Old Woman With Recurrent HR+ Breast Cancer

December 2013

• A 58-year-old postmenopausal woman was referred for further evaluation of a suspicious left-sided lesion found incidentally on routine mammogram
  • MRI revealed a 4.3-cm lesion in her left breast
  • PMH unremarkable
• She underwent lumpectomy with axillary staging
• Biopsy findings:
  • Histology: lobular carcinoma, grade 2
  • Hormone receptor status: ER+/ PR (-)
  • HER2,IHC 1+
  • OncotypeDx RS, 19
• Staging, T2N0M0
• ECOG 0
• She was started on adjuvant anastrozole

September 2018

• On routine follow-up, the patient reports increasing fatigue and intermittent bouts of abdominal pain with nausea
• CT with contrast showed several small lesions in the liver; biopsy confirmed metastatic disease.
  • The patient was started on ribociclib; anastrozole was changed to fulvestrant
  • Imaging at 3 and 6 months showed a partial response