Circulating tumor cells as predictors of prognosis in metastatic breast cancer: clinical application outside a clinical trial.
OBJECTIVE
Circulating tumor cells have a prognostic role in metastatic breast cancer. The aim of the study was to confirm the ability of circulating tumor cells, detected by the US Food and Drug Administration approved Cell Search assay, to predict the outcome of patients treated in a community general hospital.


METHODS
A prospective mono-institutional study was conducted at the Department of Medical Oncology at Spedali Civili, Brescia, Italy, from January 2009 to September 2010. A total of 93 consecutive patients with metastatic breast cancer were enrolled. Patients underwent a blood sample collection to detect circulating tumor cells at baseline and, subsequently, at the first follow-up examination (after 3-4 weeks from the beginning of a systemic therapy). A third sample was drawn at disease progression (at the beginning of a subsequent new course of therapy). The prognostic cutoff value of circulating tumor cells was fixed at 5 cells/7.5 ml of blood.


RESULTS
At baseline, median overall survival and progression-free survival in the subgroup ≥5 circulating tumor cells/7.5 ml of blood were significantly shorter (5 months and 3 months, respectively) than in the subgroup with <5 circulating tumor cells (8 months and 7 months, respectively) (P = 0.003 and P <0.001). At the first follow-up, the subgroup with more than 5 circulating tumor cells/7.5 ml of blood had a median overall survival of 4 months versus 8 months in the subgroup with <5 circulating tumor cells (P <0.001) and a median progression-free survival of 3 months versus 7 months respectively (P <0.001). At multivariate analysis, the level of circulating tumor cells at the first follow-up and at baseline remained significant as a predictor of progression-free and overall survival. The number of metastatic sites was significantly associated with overall and progression-free survival and correlated with the number of circulating tumor cells.


CONCLUSIONS
Our study confirms the role of circulating tumor cells as predictors of prognosis in metastatic breast cancer patients treated in general clinical practice.
Medical Oncology Unit, Beretta Foundation, Azienda Spedali Civili, Piazzale Spedali Civili 1, Brescia, Italy. francesca.consoli@libero.it
Francesca
F
Consoli
Salvatore
S
Grisanti
Vito
V
Amoroso
Camillo
C
Almici
Rosanna
R
Verardi
Mirella
M
Marini
Edda
E
Simoncini
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006764:Hospitals, Community; D006769:Hospitals, General; D006801:Humans; D007558:Italy / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D016896:Treatment Outcome
D014408:Biomarkers, Tumor