Abstract P6-08-02: Primary neuroendocrine carcinoma of the breast – lessons learned from a ten year analysis of the National cancer data base (NCDB)
Authors: Rose CE , Heidel RE , Bell JL , Orucevic A 
Published: February 2018

Abstract
Primary neuroendocrine carcinomas of the breast (NECB) is rare (a reported incidence &lt;5%). The significance of neuroendocrine differentiation and its impact on diagnosis, treatment and prognosis of NECB is controversial and based primarily on results from small retrospective case series reports. Our study objective is to define incidence, clinicopathologic characteristics, treatment patterns and prognosis of NECB and compare these to the most common invasive breast carcinoma (BC)-ductal (IDC).
A retrospective observational comparison study of NCDB patients (pts) from 2004 to 2014 compared all NECB pts with ICD-O-3 diagnosis codes 8246/3, 8041/3 and 8574/3 (well-differentiated neuroendocrine tumor, poorly differentiated/small cell carcinoma and invasive BC with neuroendocrine differentiation, respectively) to the same number of randomly selected IDC (8500/3) pts. Patients' clinicopathologic characteristics, treatment, and overall survival (OS) were analyzed using frequency statistics, chi-square, Kaplan-Meier and logistic regression.
1,790,023 pts had BC; 1,316,696=IDC (73.6%); 957=NECB (.0005%). NECB pts were significantly (p&lt;.05) more likely to be: older, have larger tumors, grade 3 tumors, positive lymph nodes, ER, PR, HER2-negative tumors and higher TNM stage when compared to IDC. NECB pts were less likely to undergo surgery, radiation and anti-estrogen therapy. NECB pts had significantly worse 10-year OS than IDC pts (p&lt;.001), with NECB pts being 3.4 times more likely to die in 10-years (95%CI 2.7-4.3).
Our study is the largest study to date on NECB (incidence 0.0005%) showing that NECB is aggressive and carries a significantly worse prognosis than IDC. Prospective randomized clinical trial(s) are unlikely, yet needed in order to conquer the current challenges of patients with NECB.
DemographicsNECBIDC (random sample)Adjusted Odds Ratio *=p&lt;.0595%CI95%CI N=957N=957 LowerUpper N % Age ≤4047 4.970 7.3R 41-69564 58.9616 64.4NS ≥70346 36.2271 28.31.9*1.32.8Race White809 84.5804 84R Black118 12.3105 11NS Other21 2.239 4.1NS Unknown9 .99 .9 Tumor size mm ≤543 4.588 9.4R (tumor ≤10mm) 6-1096 10.1172 18.3R (tumor ≤10mm) 11-20196 20.6339 36.1NS 21-50382 40.2264 28.13.1*2.44.1≥51160 16.851 5.46.7*4.69.9Unknown68 7.222 2.3 Grade 193 9.7181 18.9R 2208 21.7372 38.9NS 3480 50.2360 37.62.6*1.93.5Unkown176 18.444 4.6 # of node(s) positive 0372 38.9577 60.3R 1 to 3194 20.3193 20.21.5*1.21.94 to 947 4.955 5.7NS ≥10328 34.3121 12.64.2*3.35.4Unknown16 1.711 1.1 TNM stage I245 25.6502 52.5R II334 34.9293 30.62.3*1.92.9III121 12.692 9.62.7*1.93.7IV166 17.335 3.79.7*6.514.4Unknown89 9.326 2.7 ER (+)540 62.6730 78.2R (-)322 37.4203 21.8.5*.4.6PR (+)474 55.8636 68.2R (-)375 44.2296 31.8.6*.5.7HER2 (+)15 3.474 15.4R (-)428 96.6402 84.5.2*.1.3Surgery Yes724 79.4900 95.8R No188 20.639 4.2.17*.1.2Chemotherapy No335 35409 42.7R Yes622 65548 57.31.4*1.21.7Anti-estrogen tx No460 54.6292 34.2R Yes382 45.4562 65.8.4*.4.5Radiation No444 46.4398 41.6R Yes513 53.6559 58.4.8*.6.910-year overall survival Odds ratio Dead350 40.5141 16.63.4*2.74.3Alive515 59.5710 83.4 R = Referent NS = Not significant
Citation Format: Rose CE, Heidel RE, Bell JL, Orucevic A. Primary neuroendocrine carcinoma of the breast – lessons learned from a ten year analysis of the National cancer data base (NCDB) [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 P6-08-02.