Abstract P5-17-11: Trends in incidence, patient characteristics, and management of lobular carcinoma in situ
Authors: Johnson AT , Guo X , Nygaard RM , Zera RT 
Published: May 2016

Abstract
Introduction: Lobular carcinoma in situ (LCIS) is a rare lesion accounting for only 5% of total breast cancer diagnosis; however, the incidence has continued to increase, albeit at a slower rate than was seen in the 1980s and 1990s. Current National Comprehensive Cancer Network (NCCN) guidelines recommend surgical excision of the breast tissue containing LCIS due to risk of concomitant malignancy, but wide variations in treatment exist. Using the Surveillance, Epidemiology, and End Results (SEER) and National Cancer Database (NCDB) participant user files, an extensive survey of women with LCIS breast cancer was completed. Our aim was to identify patient and facility characteristics that are associated with aggressive treatment (mastectomy) or under-treatment (no surgical excision) following LCIS diagnosis.
Methods: Women with a diagnosis of LCIS from 1998 to 2011 within the SEER and NCDB databases were identified. Incidence data was gathered from SEER while all other characteristics (patient, facility, and treatment factors) were obtained from the NCDB. A logistic regression model was created to examine factors associated LCIS treatment modalities recorded in the NCDB.
Results: The incidence of LCIS increased from 3.85 to 4.46 / 100,000 women between 2000 and 2011. 62,923 female patients with LCIS were identified within the NCDB. The majority of women diagnosed with LCIS were between the ages of 40 and 59 years (66.8%, N=42,044), white (87.4%, N=55,022), and non-Hispanic (86.9%, N=54,679). Following a diagnosis of LCIS, most women underwent surgical excision (71.1%, N=44,731), with an additional 20.7% undergoing mastectomy (N=13,039) or opting for no surgery (8.0%, N=5,023). Logistic regression analysis demonstrated that age over 60 years was associated with no surgical intervention (OR 1.49, p&lt;0.001), while age 40 to 59 were associated with aggressive therapy (OR 1.19, p&lt;0.001). Economic factors associated with no surgical intervention following LCIS diagnosis include: no insurance (OR 1.24, p&lt;0.001), government sponsored insurance (OR 1.48, p&lt;0.001), live in areas with median income less than $63,000 per year (OR 0.744, p&lt;0.001), and live in an area with higher rates of the population lacking high school education (OR 1.19, p&lt;0.001). Patients undergoing aggressive treatment were more likely to be white (OR 1.57, p&lt;0.001) and carry private insurance (OR 1.87, p&lt;0.001). Patients receiving care at an academic center were more likely to receive aggressive treatment (OR 1.22, p&lt;0.001). Living farther from treatment center was associated with increased odds of aggressive therapy, but not under-treatment (p&lt;0.001 vs p=0.906, respectively).
Conclusion: Despite being a rare cancer, the incidence of LCIS continues to rise. LCIS is predominantly a cancer diagnosed in white, non-hispanic women. Advanced age, poverty, lack of insurance, low high school graduation rates were factors significantly associated with under-treatment of LCIS. Conversely, white women between 40-59 yo with private insurance and treated at a cancer center were more likely to undergo aggressive treatment.
Citation Format: Johnson AT, Guo X, Nygaard RM, Zera RT. Trends in incidence, patient characteristics, and management of lobular carcinoma in situ. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-17-11.