Table 1:

Summary of Recommendations

CEA (colorectal cancer)

Screening CEA is not recommended to be used as a screening test for colorectal cancer.

Staging/treatment planning CEA may be ordered preoperatively in patients with colorectal carcinoma if it would assist in staging and surgical treatment planning. Although elevated preoperative CEA (>5 mg/mL) may correlate with poorer prognosis, data are insufficient to support the use of CEA to determine whether to treat a patient with adjuvant therapy.

Postoperative Postoperative serum CEA testing should be performed every 3 months in patients with stage II or III disease for at least 3 years after diagnosis, if the patient is a candidate for surgery or systemic therapy. An elevated CEA, if confirmed by retesting, warrants further evaluation for metastatic disease, but does not alone justify systemic therapy for presumed metastatic disease. Since chemotherapy may falsely elevate CEA levels, waiting until chemotherapy is finished to initiate surveillance is advised.

Monitoring response to therapy CEA is the marker of choice for monitoring metastatic colorectal cancer during systemic therapy. CEA should be measured at the start of treatment for metastatic disease and every 1 to 3 months during active treatment. Persistently rising values above baseline should prompt restaging, but suggest progressive disease even in the absence of corroborating radiographs. Caution should be used when interpreting a rising CEA level during the first 4 to 6 weeks of a new therapy since spurious early rises may occur, especially after oxaliplatin.

CA19-9 (colon cancer)

Present data are insufficient to recommend CA19-9 for screening, diagnosis, staging, surveillance, or monitoring treatment of patients with colorectal cancer.

DNA ploidy or flow cytometric proliferation analysis (colon cancer)

Neither flow cytometrically derived DNA index nor %S phase should be used to determine prognosis of early-stage colorectal cancer.

p53 (colorectal cancer)

Present data are insufficient to recommend the use of p53 expression or mutation for screening, diagnosis, staging, surveillance, or monitoring treatment of patients with colorectal cancer.

ras (colorectal cancer)

Present data are insufficient to recommend the use of the ras oncogene for screening, diagnosis, staging, surveillance, or monitoring treatment of patients with colorectal cancer.

TS, DPD, TP (colorectal cancer)

Screening TS, DPD, and TP are tissue markers that have been used to predict response to treatment of established carcinomas and thus are not useful for screening.

Prognosis None of the three markers—TS, DPD, or TP—are recommended for use in determining the prognosis of colorectal carcinoma.

Predicting response to therapy There is insufficient evidence to recommend use of TS, DPD, or TP as predictors of response to therapy.

Monitoring response to therapy There is insufficient evidence to recommend use of TS, DPD, or TP for monitoring response to therapy.

MSI (colorectal cancer)

MSI ascertained by PCR is not recommended at this time to determine the prognosis of operable colorectal cancer nor to predict the effectiveness of FU adjuvant chemotherapy.

18q-LOH/DCC (colorectal cancer)

Assaying for LOH on the long arm of chromosome 18 (18q) or DCC protein determination by immunohistochemistry should not be used to determine the prognosis of operable colorectal cancer, nor to predict response to therapy.

CA19-9 (pancreatic cancer)

Screening CA19-9 is not recommended for use as a screening test for pancreatic cancer.

Operability The use of CA19-9 testing alone is not recommended for use in determining operability or the results of operability in pancreatic cancer.

Evidence of recurrence CA19-9 determinations by themselves cannot provide definitive evidence of disease recurrence without seeking confirmation with imaging studies for clinical findings and/or biopsy.

Monitoring response to therapy Present data are insufficient to recommend the routine use of serum CA19-9 levels alone for monitoring response to treatment. However, CA19-9 can be measured at the start of treatment for locally advanced metastatic disease and every one to three months during active treatment. If there is an elevation in serial CA19-9 determinations, this may be an indication of progressive disease and confirmation with other studies should be sought.

Abbreviations: CEA, carcinoembryonic antigen; TS, thymidine synthase; DPD, dihydropyrimidine dehydrogenase; TP, thymidine phosphorylase; MSI, microsatellite instability; PCR, polymerase chain reaction; LOH, loss of heterozygosity; DCC, deleted in colon cancer.