Abstract P2-13-26: Trend in primary tumor resection and disease specific survival in patients with metastatic breast cancer: A SEER database analysis (1988-2011)
Authors: Muzaffar Mahvish , Kachare Swapnil D , Fitzgerald Timothy L , Wong Jan H , Verbanac Kathryn , Vohra Nasreen A 
Published: May 2015

INTRODUCTION: The value of primary tumor resection in patients with metastatic breast cancer is a topic of ongoing debate. We aimed to analyze the trend and impact of primary tumor resection on survival over the last two decades using a national database. We hypothesized that there would be a decreasing utilization of primary tumor resection over time with an increase in disease specific survival.

METHODS: All patients with stage IV breast cancer at diagnosis between the years 1988 and 2011 were identified in the SEER database. Univariate and multivariate descriptive and survival analyses were performed.

RESULTS: A total of 41,601 patients with stage IV breast cancer were included in the study, 98.9 % (41,162) were females and 1.1% were males. Forty percent underwent surgery. Table 1 summarizes the other significant differences in demographic and tumor-related characteristics of patients who did and did not receive PTR. Over the 23- year study period there was a statistically significant temporal trend of decreased primary tumor resection (62% of patients underwent PTR in 1988, 42.4% in 2000 and 27.7% in 2011). On univariate analysis, patients who underwent PTR had a greater median disease-specific survival (DSS), (34 vs. 18 months, p&lt;0.0001). Younger age (p&lt;0.0001), non-African American race (p&lt;0.0001), lower T and N-stage (p&lt;0.0001), positive hormone receptor status (p&lt;0.0001), lower grade (p&lt;0.0001), mucinous histology (p&lt;0.0001), radiation therapy (p&lt;0.0001), and surgery performed in the latter years (p&lt;0.0001) were also associated with improved DSS. On multivariate analysis increasing age (p&lt;0.0001), AA race (p=0.0001), higher T and N stage (p&lt;0.0001), negative hormone receptor status (p&lt;0.0001), higher grade (p&lt;0.0001), no history of radiation therapy (p=0.002), and surgery in earlier years were associated with increased mortality (p&lt;0.0001). Not undergoing PTR was independently associated with increased mortality, (p&lt;0.0001).

Table 1: Comparison of patient and tumor characteristics in the surgery vs no surgery group (all p&lt;0.0001)VariableSurgeryNo surgeryFemale (%)16,328 (98.7)24,750 (99.1)White Race (%)13,198 (79.7)19,328 (77.4)T1 stage (%)3,067 (18.5)2,096 (8.4)N1 stage (%)4,173 (25.2)5,834 (23.4)ER Positive (%)9,642 (58.3)12,300 (49.3)PR Positive (%)7,532 (45.5)9,346 (37.4)Her2 Positive (%)414 (4.5)745 (3.0)Grade II (%)4,844 (29.3)5,400 (21.6)Infiltrating ductal cancer (%)11,539 (69.7)12,461 (50.0)Radiation Therapy (%)6,338 (38.3)6,937 (27.8)

CONCLUSIONS: Results from this retrospective study suggest a survival advantage in patients with stage IV breast cancer who undergo primary tumor resection. However, there has been a marked reduction in the number of patients undergoing surgery, most likely reflecting more focused patient selection. Ongoing randomized controlled trials will help address the impact of primary tumor surgery on survival of patients diagnosed with metastatic disease.

Citation Format: Mahvish Muzaffar, Swapnil D Kachare, Timothy L Fitzgerald, Jan H Wong, Kathryn Verbanac, Nasreen A Vohra. Trend in primary tumor resection and disease specific survival in patients with metastatic breast cancer: A SEER database analysis (1988-2011) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-13-26.