Abstract P2-06-14: Clinical relevance and biological properties of oligometastatic breast cancer in lung; prognostic impact of CD44+/CD24−/low cells

Abstract

Abstract Background: Metastatic breast cancer is a systemic disease. Our aim was to evaluate the clinical outcomes of pulmonary metastasectomy of recurrent breast tumors and to identify possible prognostic factors. Methods: We reviewed data from a registry of patients with lung metastases from breast tumors who received pulmonary metastasectomy in Jikei University Hospital between 2004 and 2011. We analyzed prognostic factors for overall survival (OS) and progression free survival (PFS) after metastasectomy. We also investigated lung metastases for the prevalence of CD44+/CD24−/low tumor cells and evaluated their prognostic significance. Results: Among 17 patients with lung metastasis of breast tumors, 5-year OS and PFS were 72% and 36%, respectively. Better OS was observed among patients with oligometastatic breast cancer (OMBC). Patients with OMBC, estrogen receptor (ER) positive cells, and disease free intervals (DFI) of >8 years had better PFS. The average prevalence of CD44+/CD24−/low tumor cells in lung metastases of breast cancer was 21%, ranging from 0 to 90%. The presence of CD44+/CD24−/low tumor cells influenced the progression after lung metastasectomy, with median PFS times of only 6 months in patients with high-prevalence of cancer-initiating cells. CD44+/CD24−/low cells with cancer-initiating properties were present in only 9% ± 12 of patients with OMBC but were found in 73% ± 21 of patients with non-OMBC. Conclusion: Pulmonary metastasectomy may be a treatment option for OMBC patients with lung metastases. Better prognosis of OMBC may be related to low levels of cancer-initiating cells. Citation Format: Rei Mimoto, Tadashi Kobayashi, Yoshimi Imawari, Makiko Kamio, Kumiko Kato, Hiroko Nogi, Yasuo Toriumi, Ken Uchida, Hiroshi Takeyama. Clinical relevance and biological properties of oligometastatic breast cancer in lung; prognostic impact of CD44+/CD24−/low cells [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-06-14.