Abstract P5-15-02: Indications for, and impact of oncotype DX on adjuvant treatment recommendations when third party funding is unavailable

Abstract

Abstract Background: An Australian industry-funded decision impact study demonstrated that Oncotype Dx (ODX) changed treatment recommendations (TR) in 24% of hormone receptor+/HER2- patients. ODX is available in Australia, but is self-funded by patients (∼USD 4175), so its use is limited. We sought to evaluate the impact of self-funded ODX on TRs. A high proportion of TR changes would imply a benefit to the broader community if ODX testing were available to all appropriately selected patients. Methods: All Australian physicians who had ordered >5 ODX were invited to participate. Data collected included demographics, tumor characteristics, indication for ODX (confirm need for chemotherapy (CT), confirm omission of CT, or genuine equipoise). Pre- and post Recurrence Score (RS) TRs (CT recommended versus hormone therapy alone (HT)) were also collected. The primary endpoint was the frequency and predictors of TR change. Relationships between categorical variables were assessed using Chi2 test and logistic regression analysis determined factors associated with TR change post-ODX. Results: 382 patients with median age 54 (range 31-76) were included. 18 physicians contributed a median of 17 (5-87) patients. Tumor characteristics were: T1 232 (61%); ≥T2 150 (39%); grade 1 49 (13%), grade 2 252 (66%) and grade 3 79 (21%) and Ki67>15% in 131/231 (49%). 257 (67%) were node negative (N0). Assay indications were: confirm need for CT in 36%, confirm omission of CT in 40% and genuine equipoise in 24%. RS was low in 55%, intermediate in 36% and high in 9%. Of 355 patients with a TR recorded pre-ODX, 38% had TR change post-ODX. 109/168 patients (65%) recommended CT pre-ODX changed to HT alone, and this was more likely if lower grade (82.1% vs 50.8% p<0.001) and less likely if ER and/or PR≤10% (12% vs 25% p=0.03). 27/187 (14%) with pre-ODX TR for HT alone changed to CT, and this was more likely if ER and/or PR≤10% (27.6% vs 11.5% p=0.02) and if Ki67 >15% (27.5% vs 9.8% p=0.015). Overall, TR for CT decreased from 47% to 24%. Influence of adverse prognostic factors (defined as ≥T2, grade 3, ER and/or PR <10%, nodal macrometastasis) on TR is tabulated. In 348 patients with complete data, TR changed in 31% (72/234) of N0 and 53% (60/114) of node positive (N+) patients. Number of "adverse factors"01234N0 (n=234)Number of patients90116244 RS median (range)16 (0-40)17 (0-41)26 (5-52)31 (22-40) TR change19/90 (21%)45/116 (39%)6/24 (25%)2/4 HT to CT7/71 (10%)10/61 (16%)2/11 (18%)1/2 CT to HT12/19 (63%)35/55 (64%)4/13 (31%)1/2 N+ (n=114)Number of patients22424181 RS median (range)14 (5-34)16 (0-38)14 (0-32)24 (12-50)39 TR change11/22 (50%)21/42 (50%)25/41 (42%)3/8 (38%)0/1 HT to CT3/13 (23%)3/14 (21%)0/12NANA CT to HT8/9 (89%)18/28 (64%)25/29 (86%)3/7 (43%)0/1 Conclusions: Patient self-funded ODX changed TRs in 38%. 65% who would have been recommended CT pre-ODX were spared CT post-ODX, suggesting that traditional histopathological indications for CT in ER+ patients has led to many receiving CT unnecessarily. Where the pre ODX TR was HT alone, only 14% changed to adding CT, suggesting that the indication was reassurance that CT could be omitted. Consideration could be made for third party funding in select patient groups. Citation Format: Chin-Lenn L, Segelov E, De Boer R, Marx G, Hughes TM, McCarthy N, White S, Foo S, Rutovitz J, Della Fiorentina S, Jennens R, Antill Y, Tsoi D, Cronk M, Lombard J, Kiely BE, Chirgwin J, Gorelik A, Mann GB. Indications for, and impact of oncotype DX on adjuvant treatment recommendations when third party funding is unavailable. [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 P5-15-02.