Risk of Recurrence in Stage 3B CRC

Michael Morse, MD:This is a 57-year-old man with a left-sided colon cancer. He underwent a laparoscopic colectomy and was found to have stage IIIb disease. He had 5 out of 20 lymph nodes involved. The tumor had a KRAS mutation. It was microsatellite stable. He underwent treatment with 12 cycles of FOLFOX, although the oxaliplatin was held in the last two cycles because of the development of neuropathy. Unfortunately, 6 months later he was found to have multiple hepatic metastasis and was started on therapy with FOLFIRI, plus bevacizumab.

When I see a patient with stage IIIb disease, I ask them how much detail they want to know about their prognosis. For people who want some precision, we’ll often go to one of the online calculators where we can input data that will tell us what their risk of recurrence would be without any therapy, what their risk of recurrence would be if they just had fluorouracil, and what if they had FOLFOX.

In general, for a patient with stage IIIb disease, the 5-year recurrence-free survival is about 50%. Now, if a patient takes chemotherapy with FOLFOX, that improves to almost 75%.

For a patient with stage IIIb disease, I emphasize that the highest risk of recurrence is in the first 2 to 4 years. However, we’ll certainly follow them for at least 5 years.

We explain there are ASCO guidelines and NCCN guidelines, which have a lot of similarity to each other. Essentially, if the patient is a candidate for resection for metastatic disease, for example, we’ll certainly take the most aggressive course. That would involve seeing a patient every 3 months for a physical exam and a CEA level, at least in the first 3 years, and then imaging at least once a year, if not twice a year. And that would typically consist of a chest, abdomen, and pelvic CT scan.

We also recommend a surveillance colonoscopy about 1 year after their original diagnosis. Subsequent colonoscopies can be performed based on the findings of that follow-up colonoscopy, every 5 years. Some patients may require them every 3 years.

Case Scenario 2:

• A 57-year old man presented for routine colonoscopy and was found to have a descending colon moderately differentiated adenocarcinoma. CEA pre-operatively was 6.
• Laparoscopic colectomy with colo-colonic anastomosis was performed. Final pathology showed a T3N2a (stage IIIb) lesion with 5/20 LNs positive. There was lymphovascular but no perineural invasion.
• Mutation testing revealed a KRAS mutation. The tumor was MSS.
• His ECOG performance status was 0.
• Following surgery, he was given adjuvant therapy with FOLFOX for 12 cycles with oxaliplatin help during the last two cycles because of grade 2 neuropathy.
• Six months later, follow-up imaging revealed recurrence and multiple metastatic hepatic lesions.
• The patient was started on FOLFIRI plus bevacizumab.