Abstract P3-12-26: Baseline characteristics and survival of neuroendocrine carcinoma of the breast- A SEER database analysis
Authors: Soto Alvaro Alvarez , Anampa Jesus 
Published: March 2022

Abstract
Background: Neuroendocrine carcinoma of the breast (NECB) is a malignancy. The estimated incidence of this type of tumor ranges from less than 1% to 5%. The scarcity of data about these tumors creates a challenge for treatment. Prior studies have reported that clinically most NECB behave as other type of cancer, being more common in post-menopausal women. Using population-based cancer data, our study aims to describe the baseline characteristics, tumor biology, and prognosis of patients with NECB. Methods: Using the SEER database of the National Cancer Institute, we identified 433 cases of NECB diagnosed between 2000 and 2018. We assessed the patient age, sex, race, stage, grade of the tumor and histologic type. The additional information of estrogen receptor (ER), progesterone receptor (PR) and HER2 status were also included when available. Kaplan-Meir methods were used to estimate overall survival (OS). Cox proportional-hazard model was used to create multivariable analysis for OS. Results: We found that 427 (98.6%) of the patient were female, while only 6 (1.3%) patients were male. The mean age of diagnosis was 64 years[JA1] , (SD : 14.2 years). Most patients were White (n= 353, 82%), while 52 (12%) were black, and 27 (6.2%) were other race. About the tumor histology, 375 (86.6%) cases were neuroendocrine tumor not otherwise specified, 30 (6.9%) cases were large cell neuroendocrine tumors and 28 (6.4%) were carcinoid tumor of the breast. ER was positive in 70%, PR was positive in 57% of the patients in which these receptors were tested. 194 patients were assessed for Her 2, and only 6(3%) were her2 positive. 183 (42%) had any chemotherapy use, while 250 (58%) had no known use of chemotherapy. 326 patients had a documented stage, of those 77 (17%) were AJCC stage I, 140 (32%) stage II, 39 (9%) stage III and 70 (16%) stage IV. The[JA2] median OS for stage I, II, III, and IV were not-reached, 129, 45 and 13 months, respectively[JA3] . In the univariate analysis for OS, only for tumor grade 3 (HR = 2.2; 95% CI: 1.98,2.52; p= 0.002) , ER negative (HR = 2.0; 95% CI: 1.86,3.62; p= &lt;0.001), PR (HR = 2.4; 95% CI: 2.1,2.63; p= &lt;0.001), surgery (HR = 0.26; 95% CI: 0.11,0.40; p= &lt;0.001), metastasis (HR = 0.19; 95% CI: 0.04,0.34; p= &lt;0.001), stage IV cancer (HR = 2.3; 95% CI: 2.0,2.5; p= &lt;0.001) were statistically significantly associated with OS. In a multivariate model, including age, histology, grade, ER, PR, stage group, metastasis, surgery and chemotherapy. We found that large cell histology (HR = 2.0; 95% CI: 1.0,4.3; p= 0.04), negative ER (HR = 2.0; 95% CI: 1.2,3.5; p= 0.01), negative PR (HR = 2.5; 95% CI: 1.4,4.4; p= 0.002), treatment with surgery (HR = 0.39; 95% CI: 0.22,0.69; p= 0.001), receiving chemotherapy (HR = 0.5; 95% CI: 0.31,0.79; p= 0.003), negative metastasis at diagnosis (HR = 0.05; 95% CI: 0.024,0.12; p= &lt;0.001), cancer stage (HR = 2.3 for stage II and 7.2 for stage III, p&lt;0.01. Stage I used as reference); were significantly associated with OS. Conclusion: Our study shows that NECB is a rare malignancy, and that the AJCC cancer staging can be used to adequately assess prognosis. Large cell histology, ER/PR negative, and advanced AJCC stage were inversely associated with survival, whereas chemotherapy use, surgery, and no metastasis at diagnosis, were positively associated with survival. As in other histologies of breast cancer, surgery and chemotherapy need to be strongly considered when treating NECB.
Citation Format: Alvaro Alvarez Soto, Jesus Anampa. Baseline characteristics and survival of neuroendocrine carcinoma of the breast- A SEER database analysis [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-26.