MKSAP: 58-year-old man with cancer of the ascending colon

Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 58-year-old man undergoes follow-up evaluation for cancer of the ascending colon diagnosed 3 weeks ago. Colonoscopy at that time revealed a fungating mass in the ascending colon. Biopsy revealed adenocarcinoma, and additional studies showed no evidence of metastatic disease. Right hemicolectomy was performed. The pathology report showed a 4-cm primary adenocarcinoma with clear margins at resection, full-thickness penetration through the colonic wall into pericolonic fat, and 4/21 lymph nodes involved (stage III). Medical history is otherwise unremarkable, and the patient takes no medications.

On physical examination, vital signs are normal. Examination of the abdomen shows well-healed surgical scars but is otherwise normal.

Which of the following is the most appropriate management at this time?

A. Leucovorin, 5-fluorouracil, and oxaliplatin (FOLFOX)
B. Radiation therapy
C. Radiation therapy and capecitabine followed by capecitabine plus oxaliplatin (CAPOX)
D. Observation

MKSAP Answer and Critique

The correct answer is A. Leucovorin, 5-fluorouracil, and oxaliplatin (FOLFOX).

Chemotherapy with leucovorin, 5-fluorouracil, and oxaliplatin (FOLFOX) is most appropriate for this patient with stage III colon cancer. Stage III colon cancer is potentially curable, and the likelihood of cure is modestly but statistically significantly increased by the use of adjuvant chemotherapy. Administration of leucovorin plus 5-fluorouracil (5-FU) was established as an appropriate standard adjuvant treatment for stage III colon cancer in the 1990s. However, in 2004, a large randomized trial comparing adjuvant leucovorin and 5-FU with FOLFOX adjuvant chemotherapy showed that the FOLFOX regimen led to improved disease-free and overall survival. Capecitabine is an oral prodrug that is converted to 5-FU in the body. The combination of capecitabine plus intravenous oxaliplatin (CAPOX) is also an acceptable regimen for adjuvant treatment of patients with stage III colon cancer.

Because local recurrence of colon cancer rarely develops and because it can be difficult to isolate the small bowel from the radiation field, radiation therapy, either alone or in combination with chemotherapy, does not have a role in the routine management of patients with stage III colon cancer. In addition, radiation to the small bowel may cause substantial toxicity. However, because local recurrence is a greater problem in patients with rectal cancer and because it is far easier to isolate the small bowel from the radiation field when treating rectal cancer, the combination of radiation therapy and chemotherapy, preferably preoperatively, is routinely used for treating patients with stage II and III rectal cancer.

Stage III colon cancer is potentially curable with surgery and adjuvant chemotherapy. For patients with good performance status, adjuvant chemotherapy with its associated survival advantage is preferred to observation alone.

Key Point

  • Chemotherapy with capecitabine and oxaliplatin (CAPOX) or leucovorin, 5-fluorouracil, and oxaliplatin (FOLFOX) is appropriate adjuvant therapy for patients with stage III colon cancer.

This content is excerpted from MKSAP 17 with permission from the American College of Physicians (ACP). Use is restricted in the same manner as that defined in the MKSAP 16 Digital license agreement. This material should never be used as a substitute for clinical judgment and does not represent an official position of ACP. All content is licensed to on an “AS IS” basis without any warranty of any nature. The publisher, ACP, shall not be liable for any damage or loss of any kind arising out of or resulting from use of content, regardless of whether such liability is based in tort, contract or otherwise.

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