Predictive model for sphincter preservation in lower rectal cancer

Table 6 Various prognostic factors favouring sphincter preservation surgery

Predictive parameter	Factors
Patient related	Young age, low BMI, female sex, no psychological problem, no past history of colorectal cancer, no pre operative faecal incontinence (Wexner score > 10)
Tumor related (Clinical and pathological)	Preferably T1 to T3 tumor, no involvement of inter sphincteric groove, well to moderately differentiated tumor, EAS and levator ani free from tumor, DRM-1 cm, CRM-1 mm, no distant metastasis, node negative disease
Pre-operative (Biomarkers, imaging, neoadjuvant treatment)	MSI-L status, BRAF and KRAS negative, absence of circulating tumour cells, increase in CD8+ T cell cell-free DNA, ct DNA, DRM-1cm, CRM-1 mm in MRI, good response to NACRT
Surgeon factors	Surgeon’s training, specialized colorectal surgeon, high volume colorectal cancer center

CRM: Circumferential resection margin; DRM: Distal resection margin; NACRT: Neo-adjuvant chemoradiotherapy; MSI: Microsatellite instability; BMI: Body mass index.