Experience with Use of the Oncotype DX Gene Assay Test in a Multicenter Community-Based Healthcare System

Background:Oncotype DX has been validated to quantify the risk of distant recurrence and predict the benefit of chemotherapy (CT) in ER positive, node negative breast cancer treated with tamoxifen. A retrospective study was undertaken to assess the use of the Oncotype DX test at Intermountain Healthcare. Intermountain is a not-for-profit healthcare system with 21 inpatient facilities, 9 comprehensive cancer centers and 42 affiliated medical oncologists ranging from single practitioners to multiphysician groups.Methods: This study contains a group of T1-3 N0 ER+ breast cancer patients who received an Oncotype DX test paired with a control group of non-tested T1-T3 N0 ER+ patients receiving hormone therapy (HT) from the same period. Data comes from a supplemental database containing treatment and follow-up data from individual physician offices combined with data from Intermountain's cancer registry. To ensure data completeness, Genomic Health provided a list of relevant Oncotype DX results for study patients. The analysis was done using multivariate logistic regression and controlled for age, tumor size, grade and T stage.Results: From 2005 to 2008, Oncotype DX testing was performed on tumor specimens from 285 patients. 8 patients had positive nodes and 4 patients were ER negative. In addition, 9 patients did not and will not receive HT (5 refused, 4 contraindicated) and 9 patients have yet to begin HT. 11 patients were lost to follow-up. Of the remaining 244 patients who form the study group, six patients were Her-2 neu positive (1 high recurrence score (RS), 3 intermediate and 2 low). Tumor size ranged from <1 cm to 7 cm, but 80% were <2 cm. 120 study patients (49%) had a low RS, 95 (39%) intermediate and 29 (12%) high. Only 2% of patients in the low RS group received CT, whereas 93% of patients in the high RS group and 40% in the intermediate RS group received CT.An analysis of potential factors affecting CT treatment decision making in the intermediate RS group showed that 60% of the 15 patients under age 50 received CT, compared to 36% of the 80 patients age 50 and over. CT was given in 35% of grade 1, 40% of grade 2 and 50% of grade 3 tumors. 43% of patients with a <1 cm tumor received CT compared to 42% of 1-2 cm tumors and 28% of tumors >2 cm. Compared to our control group of 688 patients, Oncotype DX-tested patients are younger (p<0.01), less likely to have T1a (p=0.03), more likely to have T1c (p<0.01) or T2 (p=0.03) tumors and less likely to undergo CT (p<0.01). Low RS patients are less likely to receive CT (p<0.01) and high RS patients more likely to receive CT (p<0.01), whereas intermediate RS patients showed no significant difference (p=0.07) but were trending toward receiving less CT than the control group.Conclusions:Virtually all patients with a low RS received only HT, while most patients with a high RS also received CT. In patients with an intermediate RS, younger age and higher grade may impact clinicians' decisions to administer CT, while a larger tumor size does not. Overall, patients undergoing Oncotype DX testing are less likely to receive CT. These data indicate that the use of Oncotype DX testing facilitated appropriate therapeutic decisions in most patients.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6058.

Impact of Recording of Pre-Analytical Specimen Handling Conditions for ER and PR Testing in Women with Breast Cancer

Background: Hormone receptor testing is important in the management of women with breast cancer. We previously reported potential adverse effects of variable specimen and prolonged specimen handling conditions on ER (estrogen receptor) test results (2005 SABCS, abstract#5107).Objective: To compare prevalence of ER and PR (progesterone receptor) negative test results following standardization of pre-analytical specimen handling conditions at Intermountain facilities.Methods: Prospective, quasi-experimental study design of 6 Intermountain facilities. Facilities were separated into 2 categories: experimental (2 facilities) and control (4 facilities) groups. Pre-analytical specimen handling conditions (including recording of time to fixative and duration of fixation in neutral buffered formalin) were standardized at experimental facilities but not at control facilities. Standardization consisted of educating operating and grossing room staff about appropriate specimen handling and the value of recording time to fixation and fixative duration as a way to improve pre-analytic standardization. OR staff was called in any cases where times were not recorded. Study population includes women undergoing breast cancer surgery and who were tested for ER/PR status between January 2008 and January 2009. Specimen handling conditions and ER/PR test results were collected manually. Covariates were retrieved from cancer registry and included age, grade, positive lymph nodes, specimen type, and tumor stage. Multivariate logistic regression was used to compare prevalence of ER and PR negativity between experimental and control facilities after controlling for covariates.Results: 1054 women with breast cancer were tested for ER/PR status during the study period. The average age was 60.2 years (59.2 years for control cases and 61.1 years for the experimental group). The overall prevalence of ER and PR negative tests was respectively 18.5% and 27.3%. Average time to fixative at experimental facilities was 18.4 minutes (SE=3.1; 95% CI, 12.2-25.6) and average time in fixative was 18.0 hours (SE=0.4; 95% CI, 17.2-18.8). Compared to experimental facilities, both the prevalence of ER and PR negativity was higher (16.9% vs 19.7%) and (23.9% vs 30.0%) at control facilities. After controlling for covariates there was no difference in prevalence of ER negativity (p=0.13) between the two groups. However, the prevalence of PR negativity remains significantly higher (p<0.01) at control facilities compared to experimental facilities even after controlling for covariates.Conclusions: The prevalence of ER and PR negative results was lower following staff education and recording of pre-analytical specimen handling conditions. Our data suggest that staff education and recording of pre-analytical specimen handling conditions has the potential to optimize hormone receptor test results. It also shows the feasibility of fixing tissue routinely after less than an hour interval between time of breast cancer tissue removal and fixation and underscores the value of standardization of pre-analytic handling as a method to improve ER and PR testing on breast cancer specimens.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4154.