Abstract P4-04-19: Endocrine medical treatment in breast cancer, is that enough?
Authors: Rosario V , Torres C , Santiago CP 
Published: February 2018

Endocrine treatment has been in the management of hormone receptor breast cancer for a few decades, but never as the first line of treatment. Now in the biomolecular era, we are able to select patients where endocrine treatment can be considered the first line of treatment.

Methods: During the months of May 2011 until June 2017, patients with ductal/lobular, in-situ and invasive cancer were treated medically with endocrine treatment as first choice of treatment (Tamoxifen/AI), due to medical morbidity or as requested by patients. The use of biomolecular assays helped to support the treatment decision. The infrastructure of ABC as a comprehensive center with all the modalities for diagnostic and interventional breast imaging center allow us to do all the follow up with the same health professionals. The assessments of the follow-ups were based on clinical, imaging (MRI, ultrasound and mammogram), and pathological responses.

We use the term "complete clinical response" on patients where the clinical history and the physical examination demonstrate complete improvement of the breast cancer. "Complete imaging response" is referred to those patients that before treatment had a breast MRI with enhancement lesions and in the follow-ups show no more enhancements. "Complete pathological response" refers to patients which had no residual cancer on the surgical specimen.

Results: We followed a total of 32 patients for an average period of 20.12 months (range=2-63 months), and an average age of 69.69 (range=45-86). Twenty-six of these patients (81.2 %) had Invasive Ductal Carcinoma, 6 patients (18.7%)had DCIS, 23 of the patients (71.88%), were only treated with endocrine treatment.Nine patients (28.13%) were treated with endocrine therapy plus surgery. The decision for surgery was a personal request of the patient, not a failure of the endocrine treatment.

The 32 patients (100%) had a complete clinical response. Twenty-five patients (78.13%) presented a complete imaging response.From the patients who had surgery,1 patient (11.11%) presented a complete pathological response, 6 patients (66.67%) presented down staging of the tumor, and 2 patients (22.22%) presented no change.

Twenty-nineof the 32 patients (90.63%) were able to obtain the recurrence score by Twenty-one Genes.Twenty-four of those had a low recurrence score, 4 had an intermediate score, and 1 patient had a high recurrence score.

Discussion: Even though this is a small group of patients, there was no failure of treatment, mortality or progress of the disease. It demonstrated that, on selective patients, the effectiveness of endocrine treatment is possible, and can be used as the first line treatment. The selection of those patients was supported with the use of the 21 genes.

Conclusion:Now days endocrine treatment, based on clinical and biomolecular assays, can be considered safe to use as first line of treatment for invasive and non-invasive breast cancer for those patients that refuse surgery or chemotherapy.

Citation Format: Rosario V, Torres C, Santiago CP. Endocrine medical treatment in breast cancer, is that enough? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-19.