19 Colorectal and Anal Cancers

Ashley Morton and Benjamin R. Tan, Jr.

QUESTIONS

Each of the numbered items below is followed by lettered answers. Select the ONE lettered answer that is BEST in each case unless instructed otherwise.

Question 19.1 A 30-year-old multigravid woman presents with a large abdominal mass associated with abdominal pain. She underwent a total proctocolectomy for colon cancer secondary to familial adenomatous polyposis (FAP) 4 years ago followed by adjuvant chemotherapy for node-positive disease. A recent esophagogastric endoscopy revealed only a tubulovillous adenoma in the duodenum but the computed tomography (CT) scan revealed a 10-cm mass filling the pelvis. Biopsy showed desmoid tumor. A TRUE statement regarding desmoid tumors is:

A. Desmoid tumors represent the second most common cause of death for patients with FAP.

B. Desmoid tumors are uniformly aggressive and locally invasive.

C. Adjuvant radiation is recommended.

D. Adjuvant chemotherapy is recommended.

Question 19.2 A 55-year-old woman underwent a right hemicolectomy for a cecal mass, 15 years ago. Four years later, she was found to have a hepatic flexure adenocarcinoma and a total colectomy was performed. Four years ago, she presented with postmenopausal bleeding and was found to have endometrial adenocarcinoma. She also had multiple skin malignancies, including sebaceous adenomas and keratoacanthomas. One year ago, she underwent a Whipple procedure for a duodenal adenocarcinoma invading into the pancreas. She has three siblings and a paternal uncle with colorectal cancer all diagnosed in their late 30s. What is the most probable primary genetic explanation for her inherited colorectal cancer syndrome?

A. Chromosomal instability characterized by the deletion or mutation of a tumor suppressor gene

B. Chromosomal instability characterized by activation of an oncogene

C. Microsatellite instability (MSI) caused by germline mutations in a DNA mismatch repair (MMR) gene

D. MSI caused by epigenetic changes associated with hypermethylation in CpG islands

Question 19.3 Other than genetic counseling, which test would you order to confirm the diagnosis in the patient in Question 19.2?

A. TP53 mutation and loss of heterozygosity of chromosome 18q

B. APC mutation, including the I1307K allele

C. MSI testing and methylation of CpG islands

D. MSI test and MMR gene mutation including MLH1, MSH2, and MSH6

Question 19.4 The patient in Question 19.3 had a positive test result. What screening tests and surveillance program would you recommend to her three daughters aged 24, 22, and 20 years?

A. Colonoscopy now and repeat every 1 to 2 years and transvaginal ultrasound for her daughters starting at age 30 to 35 years

B. Colonoscopy for all and transvaginal ultrasound for her daughters starting at age 30 to 35 years

C. Colonoscopy now and repeat every 1 to 2 years with transvaginal ultrasound at age 30 to 35 years only for her children confirmed to have the same genetic mutation as the patient; colonoscopy at age 40 to 50 years for those with no mutation

D. Colonoscopy and transvaginal ultrasound at age 30 to 35 years only for those confirmed with the same mutation as the patient; colonoscopy at age 40 to 50 years for those with no mutation

Question 19.5 Which gene is associated with hereditary nonpolyposis colorectal cancer (HNPCC)?

A. APC

B. MYH

C. STK11

D. MSH2

Question 19.6 A 65-year-old woman presented with intermittent constipation and diarrhea associated with abdominal cramping. A colonoscopy revealed a near-obstructing mass and biopsy showed a villoglandular polyp. She underwent an exploratory laparotomy and resection of a 5 × 5-cm circumferential necrotic and fungating mass. Pathology revealed a moderately differentiated adenocarcinoma invading into the pericolonic fat with 2 of 30 positive lymph nodes. Margins were negative. CT scan showed no evidence of metastatic disease. After recovery from her surgery, based on current evidence, you would recommend:

A. 5FU with leucovorin × 6 months

B. Capecitabine × 6 months

C. Irinotecan with 5FU (FOLFIRI) × 6 months

D. Oxaliplatin with 5FU (FOLFOX) × 6 months

E. Oxaliplatin with 5FU (FOLFOX) and bevacizumab × 6 months

Question 19.7 One week after the first dose of chemotherapy, the patient in Question 19.6 developed a fever of 102°F associated with chills. She also developed diarrhea, mucositis, confusion, and ataxia. Repeat complete blood count showed a white blood cell count of 0.5 × 103 cells/μL with an absolute neutrophil count of 100, hemoglobin of 11.7 g/dL, and platelet count of 42,000. Which one of the following pharmacogenetic conditions would best explain her clinical course?

A. The patient is homozygous for the thymidylate synthase (TYMS) ^*3/^*3 polymorphism.

B. The patient is homozygous for UGT1A1^*28 polymorphism.

C. The patient is heterozygous for the IVS14 + 1 G>A DPYD^*2A mutation.

D. The patient is heterozygous for the ERCC2 Lys751Gln polymorphism.

Question 19.8 A 62-year-old engineer was diagnosed with metastatic cecal adenocarcinoma to the lung and liver. He was initially treated with oxaliplatin plus infusional 5FU (FOLFOX6) and bevacizumab. After four cycles (2 months), his CT scan showed progressive disease. You discussed irinotecan 180 mg/m² every 2 weeks plus weekly cetuximab based on the results of the EPIC study. A test for UGT1A1 polymorphism was done, and results revealed him to be homozygous for UGT1A1^*28/^*28. Which of the following statements is/are TRUE?

A. Patients homozygous for the UGT1A1^*28 polymorphism glucuronidate SN38 more efficiently than those with the wild-type ^*1 genotype.

B. Patients homozygous for the UGT1A1 ^*28 polymorphism glucuronidate SN38 less efficiently than those with the wild-type ^*1 genotype.

C. Patients homozygous for UGT1A1^*28 polymorphism are at greater risk for severe neutropenia with irinotecan compared with those with the wild-type ^*1 genotype.

D. A and C are true.

E. B and C are true.

Question 19.9 A 52-year-old teacher presents with a 2-month history of rectal bleeding. A rectal examination revealed a palpable nonobstructing mass 5 cm from the anal verge. Subsequent colonoscopy confirmed a friable, tethered mass biopsy that showed moderately differentiated adenocarcinoma. Transrectal ultrasound revealed a T3N1 cancer. CT scans of the chest, abdomen, and pelvis revealed no metastatic sites. Which of the following treatment strategies would you recommend?

A. Total mesorectal excision (TME) alone

B. TME followed by chemotherapy

C. TME followed by chemoradiation

D. Neoadjuvant 5FU-based chemoradiation followed by TME and adjuvant chemotherapy

Question 19.10 Which of the following appropriately staged patients with rectal cancer would be the best candidate for transanal excision?

A. A 48-year-old woman with a 2.5-cm T1 moderately differentiated rectal adenocarcinoma 4 cm from the anal verge.

B. A 65-year-old man with a 4.5-cm T2 well-differentiated circumferential rectal mass 6 cm from the anal verge.

C. A 30-year-old man with a 2-cm well-differentiated T1 mucinous adenocarcinoma 12 cm from the anal verge.

D. A 52-year-old woman with a 3-cm well-differentiated T1N1 adenocarcinoma 5 cm from the anal verge.

E. None of the above.

Question 19.11 For the patient you have selected for transanal resection in Question 19.10, pathologic review of the excised specimen showed no lymphovascular invasion and all margins were negative. Which of the following options would you recommend?

A. No further therapy

B. Short-course (25 Gy/5 fractions) radiation

C. Intracavitary radiation

D. Adjuvant chemotherapy without radiation

E. Adjuvant chemotherapy with radiation

Question 19.12 Which of the following are TRUE statements regarding MYH-associated polyposis? (Select two correct responses)

A. Inheritance is autosomal dominant.

B. Clinical features of MYH-related polyposis may be similar to FAP.

C. The MYH gene is a base-excision repair gene.

D. A deficiency in MYH leads to accumulation of germline mutations in the APC gene.

Question 19.13 A 49-year-old woman noted rectal bleeding for 2 months. She denied any pain, diarrhea, constipation, or weight loss. A colonoscopy was done that revealed a 2-cm low-lying mass 1 cm from the anal verge. A transrectal ultrasound revealed no lymph nodes. Biopsy showed basaloid squamous cell carcinoma. CT scans of the abdomen and pelvis did not reveal any metastatic disease. The BEST curative treatment option for this patient is:

A. APR

B. Short-course (25 Gy/5 fractions) radiation followed by APR

C. Neoadjuvant chemoradiation with 5FU followed by APR

D. Chemoradiation alone with 5FU and mitomycin

Question 19.14 A 58-year-old man presented with a 6-month history of anorexia, fatigue, and a vague right-sided abdominal discomfort. His physical examination was unremarkable except for mild pallor. Initial laboratory test revealed a hemoglobin level of 10.7 g/dL with a mean corpuscular volume of 73. He also had mildly elevated alkaline phosphatase and hepatic transaminases. Colonoscopy revealed a nonobstructing transverse colon mass. Biopsy demonstrated moderately differentiated adenocarcinoma. CT scan revealed a 3-cm lesion in the left lobe of the liver and two other lesions measuring 1.5 to 2 cm in the right lobe of the liver. Positron emission tomography revealed uptake in the transverse colon and all three known hepatic lesions. Among the following options, what would be the best option for this patient based on current studies?

A. Curative-intent resection of the transverse colon primary and all three hepatic lesions followed by active surveillance

B. Palliative-intent front-line chemotherapy with bevacizumab for metastatic colon cancer until progression, followed by palliative second-line chemotherapy

C. Curative-intent resection of the transverse colon primary and all three hepatic lesions with perioperative chemotherapy

D. Curative-intent resection of the transverse colon primary and all three hepatic lesions with radiotherapy

Question 19.15 Which genetic change is associated with resistance to treatment with cetuximab?

A. KRAS mutation

B. EGFR over expression

C. KRAS wild type

D. MLH1 inactivation

Question 19.16 A 54-year-old woman has completed six cycles of first-line therapy for metastatic KRAS codon 12 mutated colon cancer with FOLFOX and bevacizumab, and was shown to have stable disease on restaging scans. Her CEA has also decreased from 135 ng/mL at initial diagnosis to 4.5 ng/mL. She is asking about taking a break from chemotherapy altogether for the next few months given the stable disease. When considering observation versus maintenance chemotherapy in metastatic colorectal cancer, you inform her that:

A. There is no benefit in maintenance therapy with capecitabine and bevacizumab and observation is preferred.

B. She should switch to FOLFIRI–panitumumab given no response noted on imaging.

C. Maintenance therapy with capecitabine and bevacizumab will lengthen the time to progression and is preferred

D. She needs to complete a total of 12 cycles of oxaliplatin-based regimen before she can consider observation.

Question 19.17 Common clinical characteristics for BRAF V600E colorectal tumors include all of the following: (Select two correct responses)

A. Male

B. Right-sided tumors

C. Low-grade features

D. MSI-H

Question 19.18 High-risk features for stage II colon cancers include which TWO of the following characteristics?

A. T4 perforated tumor

B. Moderately differentiated

C. Sampling of 0/8 lymph nodes

D. No lymphovascular invasion

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