Table 8.

Treatment algorithm: Rectal cancer, Mayo Clinic Cancer Center–Arizona.

Disease extent (stage grouping)	Surgery	Irradiation (alone or with CT)	Chemotherapy
T1-2N0M0 (I)	Low anterior or abdominoperineal resection (LAR, CAPR) and regional nodes; local excision of select lesions	Endocavitary RT, select lesions*; EBRT-CT before local excision or LAR of distal T2N0 lesions	NR as systemic treatment; CCRT: 5-FU–based with local excision of T2N0 lesions
T3N0M0 (IIA) T4N0M0 (IIB)	LAR or CAPR/regional nodes Resect after preop CCRT (or before for T3N0 lesions)	T3N0, Pre-or postop EBRT-CT 45–54 Gy† T4N0, Preop EBRT-CT 45–54 Gy IOERT	CCRT: 5-FU–based, PVI 5-FU 5–7 d/wk or as bolus with leucovorin wk 1,5; consider postop MACT
T1-2N1M0 (IIIA) T1-2N2M0 (IIIC) T3N1-2M0 (IIIB/C)	LAR or CAPR/regional nodes; Resect after CCRT (or before)	Preop EBRT-CT 45–54 Gy, preferred if TN stage known† Postop EBRT-CT, 45–54 Gy	CCRT: 5-FU–based, PVI 5-FU 5–7 d/wk or as bolus with leucovorin wk 1,5; postop MACT
T4N1M0 (IIIB) T4N2M0 (IIIC)	LAR or CAPR/regional nodes Resect after preop CCRT; IOERT‡	Preop EBRT-CT, 45–54 Gy IOERT	CCRT: 5-FU–based, PVI 5-FU 5–7 d/wk or as bolus with leucovorin wk1,5; postop MACT

^*30 Gy × 3–4 surface dose; available at Mayo Clinic Cancer Center–Rochester

^†Prefer preop CCRT for T4N0-2M0 cancers (based on physical exam and computed tomography) and for T3N0-2 or T1-2N1-2 cancers (based on endoscopic ultrasound or pelvic MRI staging)

^‡IOERT dose-dependent on amount of residual disease after maximal surgical resection: R0, 10–12.5 Gy; R1, 12.5–15 Gy; R2, 15–20 Gy

Abbreviations: CAPR, combined abdominoperineal resection; CCRT, concurrent chemoradiotherapy; EBRT, external beam radiation; EBRT-CT, external beam radiation + chemotherapy; ICT, investigational chemotherapy clinical trials; IOERT, intraoperative electron radiation; LAR, low anterior resection; MACT, multiagent chemotherapy; NR, not recommended; postop, postoperative; preop, preoperative; PVI, protracted venous infusion.