Physicians Take the Podium at Miami Breast Cancer Conference to Argue “For” and “Against” 10 Years of Adjuvant Endocrine Therapy for Patients

“Medical Crossfire” sessions like the one pitting Dr. Terry Mamounas, Medical director, Comprehensive Breast Program at the Orlando Health Cancer Institute and Professor of Surgery, University of Central Florida College of Medicine, against Dr. Reshma Mahtani, Chief of Breast Medical Oncology, Miami Cancer Institute, Baptist Health South Florida, were popular events at the recent Miami Breast Cancer Conference, and a great showcase for varying views on important issues. Dr. Mamounas and Dr. Mahtani squared off on the topic of adjuvant endocrine therapy for breast cancer patients.

Dr. Mamounas Says “Yes”

Dr. Mamounas took the position that most patients SHOULD be offered 10 years of adjuvant endocrine therapy (ET), while Dr. Mahtani argued that they should NOT.

Dr. Mamounas opened his portion of the presentation with data showing that long-term risk of breast cancer recurrence is high in ER+ patients. In fact, a substantial proportion of breast cancer recurrences occur more than 5 years after surgery, and the annual risk of late recurrence is higher in ER+ tumors than in those that are ER-. Also, the risk of recurrence continues to grow as years pass.

Turning to the specific benefits of Tamoxifen, Dr. Mamounas quoted data from the ATLAS Trial, which showed that continued Tamoxifen reduced recurrence, breast cancer mortality, and overall mortality for 10 years and beyond.

Finally, Dr. Mamounas quoted the 2014 ASCO Guidelines to support his position:

  • “Pre- or perimenopausal patients who received 5 years of Tamoxifen should be offered 10years total duration of Tamoxifen.”
  • “Postmenopausal patients who received 5 years of Tamoxifen should be offered the choice of Tamoxifen or an aromatase inhibitor for 10 years total therapy.”

Dr. Mahtani Says “No”

Dr. Mahtani opened her portion of the debate by noting that while a disproportionate number of breast cancer patients dying from their disease are ER+, breast cancer mortality is, and has been, falling in the US and UK—along with rates and risk of recurrence. She quoted an Early Breast Cancer Trialists Collaborative Group update from 2019 that noted:

“The risk of DR at 20 years after diagnosis for women with node-negative ER+ early-stage breast cancer who discontinue endocrine therapy at 5 years is likely to be about a third lower than in our previous report.”

Quoting from a compilation of data from six trials and more than 25,000 women, Dr. Mahtani shared that the absolute benefit from an additional 5 years of endocrine therapy to prevent recurrence was 3-5%.

Having addressed the benefit of additional years of endocrine therapy for patients, Dr. Mahtani then moved on to the costs. She noted, for example, the increased rates of bone fracture and death without recurrence. She noted, too, that bone toxicity from AI leads to significantly increased rates of bone pain, osteoporosis, and bone fractures, despite preventative measures such as bisphosphonates and vitamin D/calcium supplementation. Other life-threatening events linked to extended AI therapy include cardiovascular events and non-breast second cancers, Dr. Mahtani shared. Significant side effects impacting quality of life include hot flashes, sexual dysfunction, myalgias/arthralgias, and cognitive dysfunction, she noted.

At the conclusion, Dr. Mahtani advocated for an approach to extended endocrine therapy (EET) that selects candidates more carefully, noting that nodal status as well as genomic signatures “can be helpful in identifying patients who will actually benefit from EET.”