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Colorectal Cancer
Giridhar U. Adiga and Janice P. Dutcher
Questions and Answers
1. A 66-year-old female has type 2 diabetes that is well controlled on glipizide. She has mild arthritis and takes periodic NSAIDs. About 15 years earlier, she received hormone
replacement therapy for 2 years for severe hot flashes. She
takes calcium and vitamin D supplementation to prevent
osteoporosis. Which of the following factors is associated
with higher risk of colon cancer in this patient?
a. Diabetes
b. Prior hormone replacement therapy
c. Periodic use of NSAIDs
d. Calcium supplementation
Answer: a.
Diabetes is associated with increased risk for colon cancer possibly related to hyperinsulinemia and elevated
IGF-1. Hormone replacement therapy, NSAIDs, and calcium supplementation are all associated with protection
from colorectal cancer (CRC).
2. A 72-year-old male is diagnosed with stage II colon cancer after he underwent emergency surgery for intestinal
obstruction. Pathology revealed a 6-cm adenocarcinoma
of transverse colon with no angiolymphatic invasion.
None of the 14 lymph nodes resected were positive for
malignancy. Molecular studies confirm KRAS gene and
MSI-H (microsatelite instability-high). His preoperative
CEA level was 12 ng/Ml. Which of the following statements is true in this patient?
a. Mutated KRAS gene indicates familial disease
b.Absence of angiolymphatic invasion predisposes him
for higher risk of recurrence
c.Since tumor showed microsatelite instability-high, he
would benefit with adjuvant chemotherapy with 5FU
d.Preoperative CEA level ³5.0 ng/mL is a poor ­prognostic
indicator
Answer: d
KRAS gene mutation testing is useful in treatment decisions. Tumors with mutated KRAS do not respond to anti
EGFR therapies, and hence, testing for this is essential
prior to such therapies. Presence of angiolymphatic invasion is a poor prognostic factor. MSI-H tumors may be
marker of more favorable outcome and decreased benefit
from adjuvant fluoropyrimidine alone.
Refer to text under prognostic factors, adjuvant chemotherapy, and metastatic disease.
3. A 77-year-old female, is diagnosed to have malignant
polyps on screening colonoscopy. Comorbidity includes
hyperlipidemia and diet-controlled diabetes. She exercises regularly. Biopsy confirmed, following hemicolectomy, 4-cm adenocarcinoma with one of the 12 resected
lymph nodes positive for malignancy, and she is regarded
stage III. Preoperative CEA level was 196 ng/mL.
Molecular testing showed unmutated KRAS gene and
microsatellite stable. Which one of the following statements is true?
a.Age with comorbidities is a contraindication for
chemotherapy
b.No need for adjuvant chemotherapy since tumor has
unmutated KRAS and microsatellite stable
c.Adjuvant chemotherapy is indicated in lymph node
positive (Stage III) disease
d.She needs multiagent chemotherapy including cetuximab in view of poor prognostic features (elevated
CEA) and unmutated KRAS gene
Answer: c
Chronological age alone is not a contraindication for therapy. KRAS mutation status helps in treatment decisions in
metastatic disease when therapy with anti-EGFR agents
is considered. Microsatellite stable disease may be associated with poorer survival compared with MSI-H dis-
C.S. Pitchumoni and T.S. Dharmarajan (eds.), Geriatric Gastroenterology,
DOI 10.1007/978-1-4419-1623-5_63, © Springer Science+Business Media, LLC 2012
641
642
ease, which may support consideration of adjuvant
chemotherapy in select stage II patients. Cetuximab has
not been shown to be beneficial in adjuvant setting.
4. A 75-year-old retired male is hospitalized for abdominal
pain. Review of systems is significant for weakness and
weight loss of 20 lbs in the past 6 months. Laboratory
studies reveal hemoglobin of 10.4 g/dL, MCV of 71 fl,
and CEA within normal limits. A 6-cm sigmoid mass and
1-cm lesion in the left lobe of liver was identified on a CT
scan. Colonoscopy and biopsy of the sigmoid mass
confirms mucinous adenocarcinoma. Which of the fol-
G.U. Adiga and J.P. Dutcher
lowing statements regarding surgery for CRC in older
adults is true?
a.Laparoscopic surgery is associated with higher morbidity and mortality
b.Resections of hepatic metastases are considered not
feasible in older adults
c.Older patients are more likely to undergo emergency
surgery
d. Operative complications decrease with increasing age
Answer: c