Abstract P2-04-01: Decreased need for adjuvant chemotherapy treatment related to mammography detection of breast cancer in women age 65-74
Authors: Kaplan HG , Malmgren JA , Atwood MK 
Published: August 2014

Background: Federal expenditures continue to increase for Medicare eligible women age 65-74 years. It is hypothesized that the cost of mammography screening may be offset by the reduction in treatment, specifically adjuvant chemotherapy, needed for breast cancer (BC) detected at an earlier stage.

Methods: We identified women age 65-74 with invasive breast cancer from our institutional cohort database of 11,000 patients (n = 1576) that contains chart review data on method of diagnosis, hormone receptor status, stage, treatment and outcomes. Adjuvant chemotherapy treatment excluding adjuvant endocrine therapy treatment was the outcome of interest. Patients at our institution are treated in accordance with NCCN guidelines with adjuvant chemotherapy treatment prescribed according to age and stage. We used method of detection by the patient (PtD)/doctor (PhysD) or mammography (MamD) to conduct a stratified analysis of chemotherapy treatment received using a chi square test of significance and logistic regression to test the association of detection method with the outcome. As PtD and PhysD breast cancer have the same stage distribution and are both manual detection methods, they were combined for the analysis.

Results: Detection method for breast cancer among women age 65-74 was PtD = 27%, PhysD = 5% and MamD = 64%. These frequencies shift when DCIS and stage IV cases are removed from the analysis with 30% PtD, 5% PhysD, and 65% MamD. For stage I-III cases, ‘chemotherapy treatment = yes’ was 48% among PtD cases, 24% for PhysD cases and 20% for MamD cases (n = 1576). Treatment combination ‘surgery/chemotherapy/radiation’ was 39% for PtD, 20% for PhysD and 16% for MamD BC. The trend was reversed for ‘surgery/radiation/no chemotherapy’ treatment with 40% PtD, 69% PhysD and 70% among MamD cases. MamD BC cases were more likely to be stage I and less likely to be stage III [stage I: 80% MamD vs. 20% Pt/PhsD, stage III: 25% MamD vs. 75% Pt/PhysD (Pearson chi square = 250.24, p&lt;.001)]. MamD cases were more likely hormone receptor positive/her2neu negative compared to Pt/PhysD cases [70% MamD HR+/her2- vs. 30% Pt/PhysD HR+/her2- (Pearson chi square = 15.61, p = .001)] In logistic regression analysis of hormone receptor positive cases only (n = 1352), detection method was significantly associated with reduced likelihood of chemotherapy treatment corrected for stage at diagnosis [relative risk = .70, 95% CI = .51, .96, p = .25].

Conclusion: For invasive breast cancer, among mammography detected cases fifty percent fewer needed chemotherapy treatment compared to patient/physician detected cases indicating substantial treatment savings when invasive breast cancer is detected at an early stage by mammography. Mammography detection was predictive of less chemotherapy treatment independent of stage. The expense of mammography screening may be offset by reduction in need for chemotherapy treatment among women age 65-74. Chemotherapy treatment reduction should be included in cost effectiveness studies of mammography screening as well as false positive expense and disease specific mortality.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-04-01.