discussion should be held as to the risks and
benefits of single-agent fluorouracil, and this treatment should be offered in cases where the patient
or provider would like to be aggressive. Patients
with stage II cancer who have 1 or more high-risk
features are often recommended adjuvant chemotherapy. Whether treatment with fluorouracil plus
leucovorin or FOLFOX is preferred remains uncertain, and thus the risks and the potential gains
of oxaliplatin must be discussed with the individual patient. MMR status can also influence the
treatment recommendation for patients with stage
II disease. In general, patients with standard-risk
stage II tumors that are pMMR are offered MMR
with leucovorin or oral capecitabine for 12 cycles.
FOLFOX is considered for patients with MSI-high
disease and those with multiple high-risk features.
MONITORING AFTER THERAPY
After completion of adjuvant chemotherapy,
patients enter a period of survivorship. Patients are
seen in clinic for symptom and laboratory monitoring of the complete blood count, liver function tests, and carcinoembryonic antigen (CEA).
NCCN guidelines support history and physical
examination with CEA testing every 3 to 6 months
for the first 2 years, then every 6 months for the
next 3 years, after which many patients continue
to be seen annually. CT imaging of the chest,
abdomen, and pelvis for monitoring of disease
recurrence is recommended every 6 to 12 months
for a total of 5 years. New elevations in CEA or
liver function tests should prompt early imaging.
Colonoscopy should be performed 1 year after
completion of therapy; however, if no preopera-tive colonoscopy was performed, this should be
done 3 to 6 months after completion. Colonoscopy is then repeated in 3 years and then every
5 years unless advanced adenomas are present.122
The addition of chemotherapy to surgical
management of colon cancer has lowered the
rate of disease recurrence and improved long-
term survival. Adjuvant FOLFOX for 12 cycles
is the standard of care for patients with stage
III colon cancer and for patients with stage
II disease with certain high-risk features. Use
of adjuvant chemotherapy in stage II disease
without high-risk features is controversial, and
treatment decisions should be individualized.
Biologic markers such as MSI and CDX2 status
as well as patient-related factors including age,
overall health, and personal preferences can
inform treatment decisions. If chemotherapy is
recommended in this setting, it would be with
single-agent fluorouracil in an infusional or oral
formulation, unless the tumor has the MSI-high
feature. Following completion of adjuvant ther-
apy, patients should be followed with clinical
evaluation, laboratory testing, and imaging for a
total of 5 years as per recommended guidelines.
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