Radiation risks associated with serial imaging in colorectal cancer patients: Should we worry?

Table 1 Summary of follow up recommendations including imaging for patients with colorectal cancer

Ref.	History and physical	CEA	Abdominal imaging	Pelvic CT	Chest imaging	Colonoscopy	Sigmoidoscopy
NCCN 2010[3]	Q3-6m for 2 yr then Q6m for 3 yr	Q3-6m for 2 yr then Q6m for 3 yr	CT annual 3-5 yr	Annually 3-5 yr for rectal cancer patients	CT annually 3-5 yr	1 yr then as clinically indicated
PEBC 2010[4] Stage IIb-III	Q6m for 3 yr then annual for 2 yr	Q6m for 3 yr then annual for 2 yr	US Q6m for 3 yr then annual for 2 yr		CXR Q6m for 3 yr then annual for 5 yr	Yearly as long as polyps are found. If no polyps repeat 3-5 yr
ESMO 2010[5]	Colon Q3-6m for 3 yr then Q6-12m for 2 yrRectal Q6m for 2 yr		Colon CT or contrast enhanced US Q6-12m for 3 yrRectal CT 1 and 3 yr		Colon CT Q6-12m for 3 yrRectal CT 1 and 3 yr after surgery	Colon Q1 yr then Q3-5 yrRectal Q5 yr	Rectal Q3-6m for 1 yr then Q6-12m
BSG/ACGBI 2010[6]			CT within 2 yr			5 yr after surgery then 5 yr intervals
ACS 2006[7] Stage II or III						12m, then at 3 yr and 5 yr
ASCO 2005[8] Stage II or III	Q3-6m for 3 yr then at physicians discretion	Q3m for at least 3 yr	CT annual for 3 yr	Consider for rectal cancer patients	CT annual for 3 yrCXR not recommended	At 3 yr, if normal then Q5 yr	Q6m for rectal cancer patients who have not received pelvic radiation
Australia NHMRC 2005[9]	Q3-6m for 2 yr then Q6-12m thereafter	Q3-6m with clinical review	CT recommended No schedule	CT recommended No schedule	CT recommendedNo schedule	Q3-5 yr initially then Q3-5 yr	Rectal Q3-6m then Q6-12m
ASCRS/SPTF 2004[10]	Q4m for 2 yr	Q4m for 2 yr	Not recommended		CXR: insufficient evidence	3 yr after surgery then Q3 yr
NZGG 2011[11]	Q6m for 2 yr then yearly to 5 yr					3-5 yr after surgery then Q3-5 yr	Rectal Q6m for 2 yr then yearly to 5 yr

CEA: Carcinoembryonic antigen; CT: Computed tomography.