Treatment
Recommendation 1.3
➤ ACT should be offered to patients with stage IIB and stage IIC colon
cancer (i.e., T4, lesions either penetrating visceral peritoneum or
invasive of surrounding organ, respectively), with a discussion of
the potential benefits and risks of harm associated with ACT. (Weak
recommendation; EB-B-M)
Recommendation 1.4
➤ ACT may be offered to patients with stage IIA (i.e., T3) colon cancer
with high-risk features, including sampling of fewer than 12 lymph
nodes in the surgical specimen, perineural or lymphatic invasion,
poorly or undifferentiated tumor grade, intestinal obstruction, tumor
perforation, and/or grade BD3 tumor budding (≥10 buds). (Weak
recommendation; EB-B-L)
Qualifying statements:
▶ The number of risk factors should be considered as part of the shared-
decision making process. The presence of more than one risk factor
may increase the risk of recurrence; in an exploratory analysis of IDEA
collaboration data, 5-year disease free survival (DFS) was 74.8% for stage
II patients with 2 or more risk factors, compared to 87.3% for patients with
one risk factor.
▶ Circulating tumor DNA (ctDNA) was identified as an emerging potential
predictive factor, however, insufficient evidence of predictive value of
chemotherapy was available to warrant its inclusion in the list of high-risk
features within the main recommendation. The Expert Panel anticipates
that data on ctDNA will be forthcoming through prospective clinical trials,
and included in a future version of this guideline.
▶ The Expert Panel notes that there is controversy around the timing of
chemotherapy; data on this topic were not reported in the included
observational studies. In the Multicenter International Study of
Oxaliplatin/5-Fluorouracil/Leucovorin in the Adjuvant Treatment
of Colon Cancer (MOSAIC) trial of oxaliplatin in addition to
fluoropyrimidine-based chemotherapy, patients were required to have
started ACT within 7 weeks of surgery. In the Quick and Simple and
Reliable (QUASAR) trial of ACT with FU and folinic acid, therapy was
initiated within 6 weeks of surgery, where possible.
