S.N. Rai

Abstract P1-09-19: Demographic trends in clinical trial withdrawal rate within the bubble study

Introduction: There are well described barriers to clinical trial enrollment and participation among varied racial, ethnic and demographic groups. Little is known about clinical trial drop-out rate among these groups. The purpose of this study is to analyze the demographic and clinical characteristics of patients who originally signed consent and enrolled in the Bubble Study but then withdrew at a later date. The Bubble Study is a non- blinded, prospective observational cohort study designed to assess the adherence rate of adjuvant endocrine therapy among women with early stage breast cancer. Materials and Methods: From August 2012 to May of 2013, 75 women were enrolled into the Bubble Study. Demographic data (age, race and insurance status) and treatment factors (stage, surgery type, and therapy duration) were collected. Descriptive statistics (such as mean, median, standard deviation, minimum and maximum for continuous measures and frequency and percentage for discrete measures) were produced for the entire cohort and the subjects of cohort. Frequencies were compared using a Chi-square test (Fisher9s exact test when expected cell frequencies are small). Continuous measures were compared using a two-sample t test or Wilcoxon rank sum test for normally or non-normally outcome measures, respectively (Matthews and Farewell, 2007). In addition, linear and logistic regression analyses were used to explore association with different factors. Results were declared significant at significance level of 5% and all analyses are performed using SAS (2003, 2005). Results: At the time of analysis, 75 patients enrolled into the Bubble Study. Table 1 summarizes the demographic, social economic, therapeutic factors such as race, age, stage, surgery type, insurance and therapy durations and their relevant frequency and percentage are presented. The p-values are shown based on the chi square test. Blacks represented 28% of the total enrollment. Private insurance represented the majority (61.3%) of those enrolled and Medicare, Medicaid and Uninsured followed in that order (24.3%, 13% and 1.3% respectively.) In regards to race and insurance status, there was no significant difference between the enrolled group and the withdrawal group although there was a trend toward Blacks and Medicare with higher rate of withdrawal. Stage, surgery type or age did not predict for withdrawal. The most common reasons reported for withdrawal were financial and/or insurance reasons (22%), inconvenience of pharmacy pick up (13%) and preference for the prior system (9%). Conclusions: Demographic characteristics that traditionally predict for underrepresentation in clinical trial enrollment did not predict for withdrawal from the Bubble Study. Although small, this data set suggests disparities in clinical trial participation are largely due to enrollment rather than withdrawal. Larger analysis is needed to confirm these findings. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-09-19.

Abstract P2-04-07: Insurance status as predictor of repeat mobile mammography utilization: 10 year analysis of a comprehensive cancer center

Introduction: Mobile Mammography Units (MMU) have become a model of community outreach. The purpose of this study was to analyze the association between utilization of MMU and insurance status in the largest county in Kentucky. Methods: From January 2001- December 2010, our MMU performed 21,857 screening mammograms. Demographic data was retrospectively reviewed to identify insurance status and trends in utilization for each of these encounters. Insurance type was classified as Private Insurance, Public insurance/Medicaid, Public insurance/ Medicare and Uninsured. Insurance type was classified based on the patients primary insurer. Utilization was defined as once or more than 2 times in a 10 year period. Descriptive statistics related to insurance status were produced and statistical comparisons were conducted between one-visit patients (11816 patients) and more than one-visit patients (10041 patients). P-values were calculated using Chi-square test for comparison between the two groups. Odds ratio and its 95% confidence interval were provided. All calculations were performed with SAS statistical software (SAS Institute Inc., Cary, NC). Results: Uninsured and Private insured accounted for the majority of encounters (43% and 36% respectively.) Medicaid accounted for the least at 5%. The majority of women utilized the MMU once in a 10 year period (54%.) Overall, Private insured patients were more likely than Uninsured to only utilize the van once in 10 year period. (OR 1.075 (1.012-1.142) p = <.001.) Medicare patients were less likely than uninsured to utilize the van only once (OR 0.888 (0.821-0.959) p = < .001.) Medicaid utilization was similar to that of uninsured (OR 1.123 (0.981-1.279.) Among the insured subgroup, Private insurance and Medicaid were more likely than Medicare to utilize the van only once in a 10 year period (OR 1.211 and 1.266 respectively).nnView this table:nnTable 1: Insurance Type by Number of Screens (1 vs ≥2)nnnnnnConclusion: To our knowledge this is the largest database of MMU reported in the literature. Unique to our MMU program is community outreach to both public health centers and corporate venues capturing varied insurance types. In this dataset, the majority of women, regardless of insurance type utilize the van only once in a 10 year period. Interestingly, an insured subgroup (Medicare) was the most likely to utilized the van more than once in a 10 year period. Further analysis is needed to understand how race and/or screening location impacts repeat utilization as it relates to insurance. The low number of Medicaid reaching the MMU (5%) is concerning given the partnership with Public Health Centers. Understanding utilization based on insurance has implications for funding and future patterns of outreach.nnCitation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-04-07.

Increasing use of mastectomy with immediate reconstruction and contralateral prophylactic mastectomy in breast-conservation candidates: A 14-year report from a comprehensive cancer center.

1104 Background: First-line surgical options for early stage breast cancer include breast-conserving surgery (BCS) or mastectomy. We analyzed factors that influence the receipt of mastectomy and resultant trends over time.nnnMETHODSnWe analyzed the rates of mastectomy and BCS for 1,634 women who underwent up-front surgical treatment for AJCC stage 0, I or II breast cancer between 1995 and 2008 using data from the University of Louisville James Graham Brown Cancer Center Cancer Registry. We examined the trend of treatment over time and assessed the probability of receiving mastectomy using multivariate logistic regression.nnnRESULTSnOverall, 65.9% of women received BCS and 34.1% received mastectomy over a 14-year period (annual BCS rate range: 38.6-77.7%). The mastectomy rate substantially decreased from 43.5% in 1995 to 22.5% in 2004 (p=0.0007), but then increased to 51.7% in 2008 (p<0.0001). During the years between 2004-2008 (vs. 1995-2003), there was a significant increase in the rates of mastectomy performed in conjunction with immediate reconstruction (IR: 35.7% vs. 8.4%; p<0.0001) and/or contralateral prophylactic mastectomy (CPM: 22.9% vs. 3.3%; p<0.0001). Based on the multivariate analysis, the rate of receiving mastectomy was drastically higher for patients treated since 2004 (vs. prior to 2004), uninsured and government-insured (vs. privately insured) patients, patients with pT2 disease (vs. pTis or pT1), patients with pN1 disease (vs. pNX or pN0).nnnCONCLUSIONSnIn this longitudinal registry study, major independent determinants of mastectomy for early stage breast cancer include year of diagnosis, insurance status, and stage. Mastectomy rates declined until 2004, but have since increased in conjunction with IR and CPM. Additional study is needed to identify the reasons for and consequences of the reemergence of radical surgery for early stage breast cancer in the era of multidisciplinary care.