Circulating tumor cell count is a prognostic factor in metastatic colorectal cancer patients receiving first-line chemotherapy plus bevacizumab: a Spanish Cooperative Group for the Treatment of Digestive Tumors study.
BACKGROUND
The Maintenance in Colorectal Cancer trial was a phase III study to assess maintenance therapy with single-agent bevacizumab versus bevacizumab plus chemotherapy in patients with metastatic colorectal cancer. An ancillary study was conducted to evaluate the circulating tumor cell (CTC) count as a prognostic and/or predictive marker for efficacy endpoints.


METHODS
One hundred eighty patients were included. Blood samples were obtained at baseline and after three cycles. CTC enumeration was carried out using the CellSearch® System (Veridex LLC, Raritan, NJ). Computed tomography scans were performed at cycle 3 and 6 and every 12 weeks thereafter for tumor response assessment.


RESULTS
The median progression-free survival (PFS) interval for patients with a CTC count ≥3 at baseline was 7.8 months, versus the 12.0 months achieved by patients with a CTC count <3 (p = .0002). The median overall survival (OS) time was 17.7 months for patients with a CTC count ≥3, compared with 25.1 months for patients with a lower count (p = .0059). After three cycles, the median PFS interval for patients with a low CTC count was 10.8 months, significantly longer than the 7.5 months for patients with a high CTC count (p = .005). The median OS time for patients with a CTC count <3 was significantly longer than for patients with a CTC count ≥3, 25.1 months versus 16.2 months, respectively (p = .0095).


CONCLUSIONS
The CTC count is a strong prognostic factor for PFS and OS outcomes in metastatic colorectal cancer patients.
Medical Oncology Department, HC San Carlos, Madrid, Spain. jsastre.hcsc@salud.madrid.org
Javier
J
Sastre
M Luisa
ML
Maestro
Auxiliadora
A
Gómez-España
Fernando
F
Rivera
Manuel
M
Valladares
Bartomeu
B
Massuti
Manuel
M
Benavides
Manuel
M
Gallén
Eugenio
E
Marcuello
Albert
A
Abad
Antonio
A
Arrivi
Carlos
C
Fernández-Martos
Encarnación
E
González
Josep M
JM
Tabernero
Marta
M
Vidaurreta
Enrique
E
Aranda
Eduardo
E
Díaz-Rubio
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage / Q000009:adverse effects; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000068258:Bevacizumab; D000069287:Capecitabine; D015179:Colorectal Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000473:pathology; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D018572:Disease-Free Survival; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000031:analogs & derivatives; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D000077150:Oxaliplatin; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome
D061067:Antibodies, Monoclonal, Humanized; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D003841:Deoxycytidine; D000068258:Bevacizumab; D000069287:Capecitabine; D005472:Fluorouracil