Circulating tumor cells versus imaging--predicting overall survival in metastatic breast cancer.
OBJECTIVE
The presence of >or=5 circulating tumor cells (CTC) in 7.5 mL blood from patients with measurable metastatic breast cancer before and/or after initiation of therapy is associated with shorter progression-free and overall survival. In this report, we compared the use of CTCs to radiology for prediction of overall survival.


METHODS
One hundred thirty-eight metastatic breast cancer patients had imaging studies done before and a median of 10 weeks after the initiation of therapy. All scans were centrally reviewed by two independent radiologists using WHO criteria to determine radiologic response. CTC counts were determined approximately 4 weeks after initiation of therapy. Specimens were analyzed at one of seven laboratories and reviewed by a central laboratory.


RESULTS
Interreader variability for radiologic responses and CTC counts were 15.2% and 0.7%, respectively. The median overall survival of 13 (9%) patients with radiologic nonprogression and >or=5 CTCs was significantly shorter than that of the 83 (60%) patients with radiologic nonprogression and <5 CTCs (15.3 versus 26.9 months; P=0.0389). The median overall survival of the 20 (14%) patients with radiologic progression and <5 CTCs was significantly longer than the 22 (16%) patients with >or=5 CTCs that showed progression by radiology (19.9 versus 6.4 months; P=0.0039).


CONCLUSIONS
Assessment of CTCs is an earlier, more reproducible indication of disease status than current imaging methods. CTCs may be a superior surrogate end point, as they are highly reproducible and correlate better with overall survival than do changes determined by traditional radiology.
Budd
G Thomas
GT
Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. buddg@ccf.org
Cristofanilli
Massimo
M
Ellis
Mathew J
MJ
Stopeck
Allison
A
Borden
Ernest
E
Miller
M Craig
MC
Matera
Jeri
J
Repollet
Madeline
M
Doyle
Gerald V
GV
Terstappen
Leon W M M
LW
Hayes
Daniel F
DF
D001943:Breast Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000401:mortality*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008875:Middle Aged; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D015588:Observer Variation; D011379:Prognosis; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D016896:Treatment Outcome