Prognostic significance of circulating tumor cells in patients with metastatic colorectal cancer.
BACKGROUND
We demonstrated that circulating tumor cell (CTC) number at baseline and follow-up is an independent prognostic factor in metastatic colorectal cancer (mCRC). This analysis was undertaken to explore whether patient and treatment characteristics impact the prognostic value of CTCs.


METHODS
CTCs were enumerated with immunomagnetic separation from the blood of 430 patients with mCRC at baseline and on therapy. Patients were stratified into unfavorable and favorable prognostic groups based on CTC levels of > or = 3 or <3 CTCs/7.5 ml, respectively. Subgroups were analyzed by line of treatment, liver involvement, receipt of oxaliplatin, irinotecan, or bevacizumab, age, and Eastern Cooperative Oncology Group performance status (ECOG PS).


RESULTS
Seventy-one percent of deaths have occurred. Median follow-up for living patients is 25.8 months. For all patients, progression-free survival (PFS) and overall survival (OS) for unfavorable compared with favorable baseline CTCs is shorter (4.4 versus 7.8 m, P = 0.004 for PFS; 9.4 versus 20.6 m, P < 0.0001 for OS). In all patient subgroups, unfavorable baseline CTC was associated with inferior OS (P < 0.001). In patients receiving first- or second-line therapy (P = 0.003), irinotecan (P = 0.0001), having liver involvement (P = 0.002), >/=65 years (P = 0.0007), and ECOG PS of zero (P = 0.04), unfavorable baseline CTC was associated with inferior PFS.


CONCLUSIONS
Baseline CTC count is an important prognostic factor within specific subgroups defined by treatment or patient characteristics.
Cohen
S J
SJ
Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111-2497, USA. S_Cohen@fccc.edu
Punt
C J A
CJ
Iannotti
N
N
Saidman
B H
BH
Sabbath
K D
KD
Gabrail
N Y
NY
Picus
J
J
Morse
M A
MA
Mitchell
E
E
Miller
M C
MC
Doyle
G V
GV
Tissing
H
H
Terstappen
L W M M
LW
Meropol
N J
NJ
D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000068258:Bevacizumab; D002166:Camptothecin / Q000031:analogs & derivatives / Q000627:therapeutic use; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000473:pathology*; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D000077146:Irinotecan; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology*; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D009944:Organoplatinum Compounds / Q000627:therapeutic use; D000077150:Oxaliplatin; D011237:Predictive Value of Tests; D011379:Prognosis; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D000068258:Bevacizumab; D000077146:Irinotecan; D002166:Camptothecin