TABLE 2.

National Comprehensive Cancer Network recommendations ⁵ and real‐world examples of frequency of tumor assessments in patients with metastatic or unresectable cancer, by cancer type and a comparison of frequency in clinical practice

Cancer type	NCCN frequency recommendations	Real‐world frequency
Non‐small cell lung cancer
Initial CT scan findings: solid nodules or subsolid nodules with solitary ground glass nodules	6–12 months	The median number of imaging tests per patient in association with first‐line therapy varied by country, ranging between 3 (Brazil and Italy) and 14 (Japan) 6 ~2 months (US) 7
Initial CT scan findings: subsolid nodules with (solitary part solid or multiple subsolid)	3–6 months
Breast
Post‐chemotherapy	CT: Every 2–4 cycles Bone scan: Every 4 cycles	>4 imaging tests per year is considered “extreme use,” and is estimated to be 33% of US Medicare population 8
Post‐ hormone	CT: Every 2–6 months Bone scan: Every 4–6 months
Colorectal
Locoregional	6–12 months	~3 months 9
Metastatic	3–6 months
Prostate	Bone Scan: For symptoms and as often as every 6–12 months
Melanoma
Uveal	Low risk: every 12 months; medium risk: every 6–12 months; high risk: every 3–6 months	~2 months 7
Cutaneous	Frequency not indicated.