Neo-adjuvant radiotherapy in rectal cancer

Table 2 Subgrouping of localized rectal cancer assessed by magnetic resonance imaging¹ and the recommended primary treatment

Favourable “good” group	Intermediate “bad” group	Advanced “ugly” group
Mid/upper rectum	Mid/upper rectum
T1-3bLow rectum T1-2, T3aN0mrf clear	T3c/dlow rectum also includes T3bT4 with peritoneal or vaginal involvementonlyN1/N2mrf clear	T3 mrf positiveT4 with overgrowth to prostate, seminal vesicles, base of urinary bladder, pelvic side walls or floor, sacrum positive lateral lymph nodes
5 yr LFR2 < 10%	5 yr LFR2 10%-20%	5 yr LFR2 20%-100%
5 yr DFR3 < 15%	5 yr DFR3 15%-60%	5 yr DFR 30%-80%
Primary surgery (TME)4	Preop 5 × 5 Gy with immediate surgery5	Preop CRT or 5 × 5 Gy with delayed surgery6

¹The algorithm (modified from[102] with permission from the publisher Informa) does not primarily address the risk of systemic disease, although this risk also increases with the presence of many of “the risk factors”; however, not necessarily parallel to the local failure rate (LFR). The algorithm is also “too simplified”, in that a other factors like size of the mesorectum, anterior or posterior location, extramural vascular invasion (EMVI+) are also relevant.

²Calculated in the group of patients planned for surgery, i.e., irrespective of the surgical outcome. The table are valid if the surgeon is an experienced rectal cancer surgeon and no pre-treatment is given.

³The 5-year risk of distant failure (DFR) is also given, although this risk is not well established. Risk factors detectable on magnetic resonance imaging for distant failure are N2 (versus N0 and N1), EMVI+, mrf+ and all T4 (a and b, see Table 1). These are also the risk factors used in the ongoing trial[88], where patients at high risk failing systemically are included.

⁴A local procedure is possible in a few patients [chiefly pT1, sm1 (+ 2), N0]. This group is in the text referred to as “very favourable”.

⁵Preoperative chemotherapy (CRT) is also a valid option according to international clinical guidelines[21].

⁶CRT means chemoradiotherapy to 50.4 Gy in 1.8 Gy fractions with 5-fluorouracil (capecitabine). 5 × 5 Gy with delayed surgery should be used only in patients not fit for CRT.