Diagnosing and Managing Stage IV Right-Sided CRC

Bassel F. El-Rayes, MD:We have seen a big improvement in the outcome of patients with colorectal cancer [CRC], especially the group with stage IV disease. The improvement in outcome has resulted in an improvement in the survival from around the median of around 6 months to a median of around 30 months in recent studies. This improvement of survival comes from a better understanding of the biology of the disease, better treatment, and better multidisciplinary care for patients with stage IV colon cancer.

A 75-year-old male patient presented to his primary care physician with rectal bleeding, weight loss, and constipation. Workup included a colonoscopy, which revealed a mass in the ascending colon. A biopsy revealed invasive adenocarcinoma. Then staging was done using a CAT scan, which revealed multiple liver lesions including a 3-centimeter mass in the right lobe of the liver.

He subsequently had molecular testing, which showed that he wasRASandBRAFwild-type. In addition, he was microsatellite stable. The patient underwent, from a management point of view, a diverting colostomy and then was started on FOLFOX [folinic acid, fluorouracil (5-FU), and oxaliplatin] and bevacizumab. Scans at 3, 6, and 9 months revealed a good response. He was shifted over to a maintenance regimen of capecitabine with bevacizumab. After around 12 months, the scan showed progression of these.

With stage IV colon cancer, unless the patient has resectable metastatic disease, the goal of therapy is still control of the tumor, and there’s not a curative therapy. The cornerstone of treatment is with systemic chemotherapy combined with targeted drugs such as bevacizumab. On the average, patients withRASandBRAFwild-type colon cancer nowadays survive somewhat above 30 months, on the average. And we have patients who survive significantly longer than that as well.

It’s very important, as we manage patients with stage IV colon cancer, to consider a multidisciplinary approach where a team of experts, including medical oncologists, surgical oncologists, and radiologists, confer on the management of patients. Identifying patients with limited metastatic disease could enable us to incorporate surgery as part of the treatment in addition to systemic therapy. We know from long experience with doing surgery on liver metastases from colon cancer that a proportion of patients who undergo surgery on liver metastases can be cured with surgical interventions, and that’s why it’s important to be aware of this and to incorporate a plan to have a multidisciplinary approach to these patients from the get-go.

With respect to our patient that we’re discussing today, given the extent of liver metastases, he was not a good candidate for surgical resection. But for patients who have lower burden of disease in the liver, resection is still an important option to consider in the management of stage IV colon cancer.

Transcript edited for clarity.

Case: A 75-Year-Old ManWithRight-Sided mCRC

Initial presentation

• A 75-year-old Caucasian man presented to his PCP with rectal bleeding, fatigue, weight loss, and constipation

Clinical workup

• Colonoscopy: fungating mass in the ascending colon
• Biopsy: invasive, poorly differentiated adenocarcinoma
• Imaging: CT scan of the chest/abdomen/pelvis showed multiple small liver lesions including a 3-cm mass in right lobe
• Molecular testing on tissue biopsy:
  • KRAS, RAS, andBRAFWT
  • Microsatellite-stable
• ECOG PS 1

Treatment

• Patient underwent a diverting colostomy without complication
• He was started on FOLFOX and bevacizumab
• Follow up imaging at 3, 6, and 9 months showed a partial response
• He was continued on bevacizumab and underwent capecitabine maintenance
• Imaging at 12 months showed 2 new liver lesions (1.2 cm and 3.4 cm)