‘A true victory’
Invited discussant Benjamin D. Smith, MD, of the University of Texas MD Anderson Cancer Center in Houston, pointed out that in randomized clinical trials, approximately 60% of patients treated for early breast cancer did not experience recurrence in the absence of radiation, and that radiation prevented recurrence in about 30%, while about 10% experienced recurrence despite receiving radiation.
He said that the study by Dr. Sjöström and colleagues asks the question “can we use molecular factors to help identify patients who will not recur with lumpectomy alone without radiation therapy?”
The 60% of patients who will not experience recurrence in the absence of radiation can be categorized into two subpopulations: those with no residual malignant clonogens – the population included in this study by Dr. Sjöström and colleagues – and those with residual clonogens in the breast or elsewhere in the body that are sensitive to adjuvant endocrine therapy.
He said that the 7% 10-year risk of recurrence among patients in the POLAR low-risk group, who had neither radiation nor endocrine therapy, “is an exceptional outcome, which should be applauded, and I would point out that this risk of local recurrence of only 7% is at least in the same ballpark as the risk of recurrence that we accept every day when we treat early stage breast cancer patients with mastectomy alone, so this is a true victory.
“When we reflect on these provocative results from Dr. Sjöström and colleagues, it prompts in mind the question, could there be a group of patients with early breast cancer for whom a true ‘one-and-done’ strategy could be effective and safe?” Dr. Smith said.
Getting there will require a multidisciplinary, multimodality approach, involving imaging features of the primary tumor, clinical and pathologic features, and molecular information such as that provided by the POLAR genomic signature, he said.
The study was supported by PFS Genomics. Dr. Sjöström reported institutional funding from PFS Genomics. Dr. Speers disclosed stock and other ownership interests in the company, and he has applied for a patent on methods and genomic classifiers for prognosis of breast cancer and predicting benefit from adjuvant radiotherapy. Dr. Smith reported an equity interest in Oncora Medical, and an uncompensated relationship with the American Society for Radiation Oncology.