Abstract P2-08-27: Prediction of bone metastases of breast cancer using combined markers of bone metabolism and inflammation

Introduction Luminal breast cancer patients show a relatively favorable prognosis when treated with adjuvant hormonal therapy alone. However, some of these patients develop recurrence and they might derive benefit from adjuvant chemotherapy. Although several genomic profilings successfully developed to decide whether to administer adjuvant chemotherapy, clinically practical prediction methods of recurrence sites do not exist. Our previous study showed a possible prediction of bone metastases by using two serum markers; TRACP-5b as a marker of bone metabolism; likelihood of bone metastases, and CRP as a marker of inflammation; likelihood of distant recurrence. The incidence of bone metastases was significantly higher in high risk patients(+/+) than in the others(odds ratio: 10.9, P=0.040). In this study, we examined the potential of the two-marker prediction in the newly enrolled luminal patients. Patients and methods One hundred sixty luminal patients who underwent surgery were enrolled in this study. Their serum levels of TRACP-5b and CRP were measured in a blinded manner at the R & D laboratory of Nittobo Medical Co., Ltd. In the preliminary study, we identified that the median value of TRACP-5b in the premenopausal patients was lower than in the postmenopausal patients. We adjusted the value of TRACP-5b in the premenopausal patients and the cutoff value of TRACP-5b from 334 to 396mU/dL. The cutoff value of CRP was same as previous study(0.016 mg/dL). The odds ratio between +/+ and the others were calculated using MedCalc statistical software. Results One hundred sixty patients stratified into four classes according to the value of TRACP-5b and CRP: +/+ (n=43), +/- (n=38), -/+ (n=42) and -/- (n=37). Six of the 160 patients developed bone metastases as the initial site of replase within five years from surgery. The Incidence of bone metastases was 9.3%(4/43) in the +/+ patients and 1.7%(2/117) in the others. The incidence was significantly higher in the +/+ patients than in the others(odds ratio: 5.9, 95% CI 1.31 to 33.46, p= 0.045). When the other relapses than bone metastases were included in the analysis, no significant difference was observed between the two groups (odds ratio: 0.4, 95% CI 0.02 to 7.43, P=0.521). TRACP-5b concentration alone could not classify the patients into two groups according to significantly different incidences of bone metastases(odds ratio: 13.7, 95% CI 0.76 to 247.22, P=0.076). Conclusion The results in here show that the prediction of bone metastases by the combination of TRACP-5b and CRP concentrations is clinically relevant in the luminal patients. Reliable prediction of bone metastases would be realized by combination of our prediction method and one of genomic profilings. We plan to increase the number of patients to provide sufficient statistical power to confirm this diagnostic potential. Citation Format: Shimoda M, Nishimukai A, Shibata N, Kikuchi W, Hutawatari H, Ishihara H, Miyoshi Y, Noguchi S. Prediction of bone metastases of breast cancer using combined markers of bone metabolism and inflammation. [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 P2-08-27.