Sidedness matters: Colon cancer outcomes in low-resource settings

Table 1 Clinicopathological and molecular differences between right- and left-sided colorectal cancer

Clinical characteristic	Right	Left
Clinical presentation	More common in older patients, women, and individuals of African descent	More common in younger patients, men, and White populations
MMR or MSI	dMMR more frequent (25.5% in ascending colon)	pMMR more frequent (7.6% in sigmoid colon)
	Higher MLH1 promoter hypermethylation[11]	Lower MLH1 promoter hypermethylation[11]
KRAS and NRAS	Similar frequencies (46.3%)	Similar frequencies (35.8%)
BRAF	More frequent (16.3%)	Less frequent (4.3%)
CMSs	CMS1 and CMS3	CMS2 and CMS4
Response to anti-EGFR therapy	Low response	Favorable response
Prognosis[32]	Stage III 5-year OS: 66.9%	Stage III 5-year OS: 81.8%
	Stage IV 5-year OS: 40.4%	Stage IV 5-year OS: 54.9%

MMR: Mismatch repair; MSI: Microsatellite instability; KRAS: Kirsten rat sarcoma viral oncogene homolog; NRAS: Neuroblastoma RAS viral oncogene homolog; BRAF: V-raf murine sarcoma viral oncogene homolog B1; CMS: Consensus molecular subtype; dMMR: Deficient mismatch repair; MLH1: MutL homolog 1; EGFR: Epidermal growth factor receptor; OS: Overall survival; pMMR: Proficient mismatch repair.