Surveillance Protocols for Bowel Cancer

Introduction to Surveillance

The American Society of Clinical Oncology (ASCO) and the American College of Gastroenterology recommend CEA monitoring as part of standard surveillance protocols for patients with stage II or III bowel cancer during adjuvant chemotherapy, with a strength of evidence level of II 1, 2, 3, 4
Elevated CEA levels (>5 ng/mL) require further evaluation, including colonoscopy, chest, abdominal, and pelvic CT scans, and careful physical examination, as recommended by the National Comprehensive Cancer Network 4

CEA should be monitored every 3 months in patients with stage II or III bowel cancer during adjuvant chemotherapy, and every 6 months for 5 years in patients with stage I disease, as recommended by ASCO and the American College of Gastroenterology, with a strength of evidence level of II 1, 2, 3, 4

The recommended CEA testing schedule is:

Stage	Frequency	Duration
I	every 6 months	5 years
II-III	every 3 months	3 years, then every 6 months until 5 years postoperatively
IV after R0 resection/destruction of metastatic lesions	every 3 months	first 3 years, then every 6 months until 5 years

Caution should be exercised when interpreting rising CEA during the first 4-6 weeks of chemotherapy, as spurious early rises may occur, especially after oxaliplatin use, according to the American College of Clinical Oncology 1
Two consecutive rising values above baseline suggest disease progression, with a strength of evidence level of II, and non-cancer causes of CEA elevation should be ruled out 1

Elevated CEA levels (>5 ng/mL) require a systematic evaluation to rule out colorectal cancer and other malignancies, as well as consideration of non-malignant causes, as recommended by the American College of Clinical Oncology 1
A complete colonoscopy (if not done within the past year) should be performed to rule out colorectal cancer in patients with elevated CEA (>5 ng/mL) and elevated ferritin, as recommended by the American College of Clinical Oncology 1
Breast cancer workup (mammogram, ultrasound) and lung cancer evaluation should be considered if clinically indicated in patients with elevated CEA and ferritin, as recommended by 5, 6
The primary imaging modality for diagnosing carcinomatosis is a CT scan with contrast enhancement of the chest, abdomen, and pelvis, as recommended by the British Journal of Cancer 7

Liver disease, inflammatory conditions, smoking status, and certain medications (such as lithium) can cause reversible CEA elevation, and should be assessed and addressed in patients with elevated CEA, as recommended by the American College of Clinical Oncology 1
Elevated ferritin alone is not a reliable marker for malignancy and is more commonly associated with inflammation, liver disease, or iron overload conditions 1

The sensitivity and specificity of tumor markers are as follows:
Marker Sensitivity Specificity
CEA 80-88% 70%
CA 19-9 59% not specified
1, 8
False-positive rates of CEA elevation range from 7-16%, and false-negative rates can be up to 40% 9
CEA should not be used as a diagnostic test due to low sensitivity, as stated by the American Society of Clinical Oncology 9

Marker	Sensitivity	Specificity
CEA	80-88%	70%
CA 19-9	59%	not specified

For selected patients with limited peritoneal disease, complete surgical removal of all visible tumor implants followed by heated chemotherapy perfusion of the peritoneal cavity may improve progression-free and overall survival, according to the Annals of Oncology 10
Patient selection criteria for this treatment include good performance status, limited intraperitoneal tumor dissemination (PCI < 20), limited small bowel disease, and no extra-abdominal metastasis, as outlined by the Annals of Oncology 10
Elevated preoperative CEA levels (>5 ng/mL) correlate with poorer prognosis in patients with colorectal cancer, and CEA monitoring, combined with regular imaging studies, has been associated with a significant reduction in mortality and earlier detection of recurrence, especially in patients with stage II or III colorectal cancer, as recommended by ASCO, with a strength of evidence level of II 1, 2, 8
Intensive follow-up including CEA testing has been associated with a significant reduction in mortality (7-13% improvement in overall survival), as reported by the American Society of Clinical Oncology 1, 9

The American Society of Clinical Oncology does not recommend the use of certain biomarkers, including DNA ploidy, flow cytometric proliferation analysis, p53 expression or mutation, ras oncogene, lipid-associated sialic acid (LASA), thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP), microsatellite instability (MSI), and 18q/DCC for routine clinical use in colorectal cancer management, with a strength of evidence level of I 1, 8