Abstract SP027: Treatment differences and consequences

Breast cancer is the deadliest cancer among women worldwide, with a total of over half a million deaths annually impacting both developed and developing countries. With an estimated 276,480 breast cancer cases projected to occur in women in the U.S., it is estimated that 42,170 women will die in 2020 due to this devastating disease. Despite the decrease in breast cancer mortality rates seen in recent years, the magnitude of that decrease in not similar across populations. In the U.S the burden of cancer is not shouldered equally. It is well known that racial and ethnic minority populations are more likely to experience cancer health disparities. While potential contributing factors associated with this phenomenon include the fact that certain groups of patients are more likely to be diagnosed with more advanced stages and to have tumors with more aggressive biology, sociodemographic factors and difficulty accessing medical care play an important role. Unfortunately, cancer care delivery is not the same for all and this can seriously hinder the cancer outcomes of those affected. Across the cancer care continuum -from screening, diagnosis, and all the way to treatment, survivorship or end-of life care-, important disparities exist leading to worse outcomes. It has been well described that Black and Hispanic women are less likely to receive appropriate and timely breast cancer treatment. Furthermore, the complex, and in many cases long treatments needed to achieve the desired outcomes, force patients to face issues associated with navigating the health care system, making life changes to accommodate treatment, and ensuring continuation and treatment adherence. In this presentation, we will review the complexities of breast cancer diagnosis and treatment and review some of the data regarding the detrimental impact associated to treatment delays. Improving cancer care delivery and ensuring access to timely and high-quality care should be a priority. We will briefly revise some of the strategies designed to overcome health disparities and hopefully, improve breast cancer outcomes.

Citation Format: M Chavez Mac Gregor. Treatment differences and consequences [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP027.

Abstract P3-08-18: Clinicopathological characteristics associated with intermediate and high-risk ODx RS

Background: The gene expression profiling assay OncotypeDx (ODx) prognosticates the risk of estrogen receptor positive (ER+) breast cancer (BC) recurrence and assesses the likely benefit from adjuvant chemotherapy in addition to endocrine therapy. There have been several attempts to develop algorithms that provide similar outcome prediction to the ODx assay with the use of routine clinicopathological characteristics. These models appear to predict high-risk ODx RS but are unable to reliably rule out the presence of patients with intermediate-risk disease. Our objective was to identify the clinicopathological factors associated with intermediate and high-risk categories.

Methods: We retrospectively reviewed the electronic medical records of patients with early-stage ER+ BC for whom ODx recurrence score (RS) was available. Patients were diagnosed and treated at 3 specialized cancer centers between 2010 and 2017. Two multinomial logistic regression models (crude and adjusted) were constructed to assess the association between clinicopathological characteristics and ODx RS as a categorical variable. The adjusted model included the following variables: ODx RS, age, tumor size, node status, grade, lymphovascular invasion and hormonal receptors. The reported association measure was the relative prevalence ratio (RPR) with its respective 95%CI.

Results: A total of 551 patients were included. Patients had a mean age of 56.2 ± 11.9 (SD) (range: 26-89). 9.6% (n=53) of patients were≤40 years old.The size of the tumors ranged from 0.1 cm to 7.2 cm (median = 1.5 cm; IQR 1.0-2.2cm). A minority of patients had lymph node involvement (5.8%, n=32). By subtype, carcinomas were mostly ductal (83.5%, n=460), followed by lobular (10.0%, n=55) and mucinous (3.5%, n=19). The majority of tumor exhibited an intermediate histological grade (71.6%, n=386). Ki 67 was available in 58.8% patients (n= 324), with a median Ki67 of 20 (IQR 10-30). In the adjusted multinomial logistic regression model, factors associated with ODx intermediate-risk category were grade 3 (RPR=4.78; 95%CI: 2.01-11.39) and having either ER or PR <50 (RPR=2.80; 95%CI: 1.83-4.27). Factors associated with ODx high-risk category were grade 3 (RPR=15.89; 95%CI: 3.23-78.19), having either ER or PR <50 (RPR=4.58; 95%CI: 2.37-8.87), age≤40 (RPR=2.96; 95%CI: 1.20-7.29) and T2-3 (RPR=2.20; 95%CI: 1.13-4.32).

Conclusion: Grade 3, ER o PR <50, age ≤40 years and T2-3 are clinicopathological characteristics strongly associated with high-risk ODx RS. The associations with intermediate-risk ODx RS are weaker. The way these factors could be integrated into a clinicopathologic risk prediction model to identify high-risk patients needs further analysis.

Citation Format: Ruiz R, Morante Z, Namuche F, Urrunaga D, Leon M, Ziegler G, Aguilar A, Chavez Mac Gregor M, Gomez H. Clinicopathological characteristics associated with intermediate and high-risk ODx RS [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-18.

Abstract P3-08-16: Age's importance in early breast cancer: Oncotype Dx results in patients ≤40 years

Background

The 21-gene recurrence score (RS) predicts the benefit of adjuvant chemotherapy (CT) in ER-positive HER2-negative breast cancer (BC) and has been validated in population where women under 40 are underrepresented.Young BC pts are more likely to receive adjuvant chemotherapy (CT) in addition to endocrine therapy (ET). Our objective was to assess the RS results in young (≤40 yo) vs older (>40 yo) pts and evaluate the impact of age on clinical decision-making according to RS categories.

Methods

We retrospectively reviewed electronic medical files of all patients with early stage hormone receptor BC for whom RS was available between 2007 and 2017 in 3 specialized cancer centers. We used the Mann-Whitney and Chi-squared tests to assess differences between age group. Similarly, we evaluated the association between age groups and treatment, within each ODx category. To determine if age was associated with CT use in the low risk category, a logistic regression model was constructed.

Results

A total of 551 pts were included, 53 (9.6%) ≤40 yo and 498 (90.4%) >40 yo. No statistical differences were found between the younger and older groups in T (p=0.874), N (p=0.794), stage (p=0.188), or grade (p=0.791). Young patients underwent radical surgery more frequently than their older counterparts (41.5 vs 25.7%, p=0.014). Statistically significant differences were also observed in ER mean, which was lower in the younger group (80 vs 90%, p<0.001). The median RS result was significantly higher in the younger group (19 vs 16, p=0.009). Also, high-risk recurrence score category was significantly more frequent in the younger group (22.6 vs 9.2%, p=0.009). In the intermediate-risk category there were no differences in the proportion of patients who received CT according to age groups (p=0.484). In the low-risk category, 28.0% of patients ≤40 years vs 11.3% of patients >40 years received CT (p=0.037).

Conclusions

Our results indicate that RS tends to be higher in patients with BC ≤ 40 yo and that the frequency of high-risk RS is significantly higher in the younger group, suggesting biological differences between groups. 28% of young patients with low-risk RS from our cohort are overtreated. Based on these results, it should be considered to develop a test adjusted to the age of the patients.

Citation Format: Ruiz R, Namuche F, Morante Z, Aguilar A, Urrunaga D, Ziegler G, Chavez Mac Gregor M, Leon M, Gomez H. Age's importance in early breast cancer: Oncotype Dx results in patients ≤40 years [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-16.

Abstract P3-08-17: Evaluation of Oncotype DX testing and subsequent treatment choices in the Latin American setting

Background: The gene expression profiling assay OncotypeDx (ODx) prognosticates the risk of estrogen receptor positive (ER+) breast cancer (BC) recurrence and assesses the likely benefit from adjuvant chemotherapy in addition to endocrine therapy. Numerous clinical utility studies have shown that acknowledging the RS impacts on clinical decision making, leading to a decrease in chemotherapy (CT) use. However, the cost of the assay limits it widespread use, especially in low and middle-income countries. Our objective was to determine the patterns of use of ODx, its results and the subsequent treatment choices in a large Latin American cohort.

Methods: We retrospectively reviewed the electronic medical records of patients with early-stage ER+ BC for whom ODx recurrence score (RS) was available. Patients were diagnosed and treated at 3 specialized Peruvian cancer centers between 2007 and 2017. Descriptive results for numeric variables were presented as means with standard deviation (SD) or medians with interquartile range (IQR), depending on their distributions; otherwise, we expressed the qualitative variables as numbers with percentages. We evaluated the association between ODx RS category and treatment using the Chi-squared test.

Results: A total of 551 patients were included. Patients had a mean age of 56.2 ± 11.9 (SD) (range: 26-89). 9.6% (n=53) of patients were ≤40 years old. The size of the tumors ranged from 0.1 cm to 7.2 cm (median = 1.5 cm; IQR 1.0-2.2cm). 36 (6.5%) patients had tumors ≤ 0.5cm and 7 (1%) had tumors > 5cm. A minority of patients had lymph node involvement (5.8%, n=32). ODx was ordered in 55 cases (10%) of lobular carcinoma and in 23 cases (4%) of favorable histology tumors (19 mucinous, 4 tubular). Most tumors exhibited an intermediate histological grade (71.6%, n=386). Ki67 was available in 58.8% patients (n= 324), with a median Ki67 of 20 (IQR 10-30). Using commercial cutoffs RS was distributed as follows: low (0–17) = 316 (57.4%), intermediate (18–30) = 177 (32.1%), and high (≥31) = 58 (10.5%). In general, 57.5% (n=317) of patients received endocrine therapy (ET) as their only systemic treatment and 42.5% (n=234), also received CT (ET + CT). In the low-risk category, 87.3% (n=276) of patients received ET and 12.7% (n=40), ET + CT. Within the intermediate-risk category, most patients received ET + CT (77.4%, n=137). Only one patient in the high-risk category did not receive CT. There was a significant association between the RS group and treatment choice (p<0.001).

Impact of ODx RS results on treatment recommendations Oncotype risk categories  LowIntermediateHighp valueTreatmentn%n%n%<0.001Endocrine therapy27687.34022.611.7 Chemotherapy + Endocrine therapy4012.713777.45798.3 

Conclusion: ODx significantly influenced treatment decisions in our cohort, however an overutilization of CT was found in low-risk patients. Further data analysis is needed to explain the higher than expected use of CT. Also, there is room for improvement in the selection of cases that undergo ODx testing.

Citation Format: Ruiz R, Morante Z, Namuche F, Urrunaga D, Aguilar A, Schwarz J, Leon M, Ziegler G, Chavez Mac Gregor M, Gomez H. Evaluation of Oncotype DX testing and subsequent treatment choices in the Latin American setting [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-17.