Serum tumor markers in colorectal cancer staging, grading, and follow‐up

Early diagnosis of colorectal cancer, a frequent neoplasia in industrialized countries, permits curative surgery. In this study we assessed the clinical role of serum tumor markers determination in diagnosing, staging, and grading colorectal cancer; the role of carcinoembryonic antigen (CEA), CA 19‐9, tissue polypeptide antigen (TPA) and CA 72‐4 in colorectal cancer follow‐up was also assessed. In 114 patients with colorectal cancer, the oncofetal antigen CEA was compared with the membrane‐associated glycoproteins CA 19‐9, CA 242, and CA 72‐4 and with the cytokeratins TPA, tissue polypeptide‐specific antigen (TPS) and tissue polypeptide monoclonal antigen (TPM). Overall, the most sensitive indices were TPA and TPS (67% and 70%, respectively). Tumor stage influenced the levels of CEA, CA 19‐9, and TPA, but not those of TPS, while tumor grade influenced CEA and TPS, but not CA 72‐4, TPA, and TPM. TPA was the most sensitive index in identifying early or well‐differentiated colorectal cancers. The sensitivity was enhanced when this marker was determined in combination with CEA, in diagnosing both advanced and early colorectal tumors. Seventy‐seven patients were followed up after therapy for at least 18 months. CEA was the most sensitive index of recurrence (58%); however, this sensitivity is too low to consider tumor markers useful in colorectal cancer follow‐up. © 1996 Wiley‐Liss, Inc.