What's the next step for a patient with colorectal cancer and new metastatic findings after FOLFOX / Avastin treatment?

Management of Colorectal Cancer Patient with New Metastatic Findings

The next step for this patient with colorectal cancer showing new FDG-avid retroperitoneal lymph nodes, new hepatic lesions, and focus of intense FDG uptake in the surgical bed is to perform a colonoscopy to evaluate the surgical bed abnormality, followed by consideration of alternative systemic therapy regimens.

Assessment of Current Situation

The patient has:

• History of colorectal cancer treated with FOLFOX/avastin
• Status post sigmoid rectum resection
• Currently on FOLFIRI and avastin (started January 2025)
• Recent imaging showing:
  • Stable hepatic metastatic lesions on chest CT
  • New FDG-avid retroperitoneal lymph nodes on PET/CT
  • New FDG-avid hepatic lesions on PET/CT
  • Intense FDG uptake in surgical bed

Recommended Management Algorithm

Step 1: Evaluate the Surgical Bed

• Perform colonoscopy to assess the suspicious area in the surgical bed showing intense FDG uptake
• This is consistent with NCCN guidelines recommending colonoscopy for follow-up of colorectal cancer patients, especially when there are concerning findings 1

Step 2: Confirm Disease Progression

• The new FDG-avid retroperitoneal lymph nodes and hepatic lesions strongly suggest disease progression on current FOLFIRI/avastin regimen
• Biopsy of accessible new lesions should be considered if there's any uncertainty about the nature of progression

Step 3: Systemic Therapy Modification

• Given disease progression on both FOLFOX and FOLFIRI regimens, consider alternative treatment options:
  • If KRAS wild-type: Add or switch to an anti-EGFR agent (panitumumab or cetuximab) 1
  • If KRAS mutated: Consider FOLFOXIRI (if not previously used) or clinical trial options 1
  • Evaluate for potential targeted therapy based on molecular profiling (HER2, BRAF, MSI status)

Step 4: Evaluate Resectability

• Have a multidisciplinary tumor board review the case to determine if any of the metastatic sites are potentially resectable 1
• If liver metastases appear potentially resectable after response to therapy, surgical consultation should be obtained

Important Considerations

Monitoring Response

• After initiating new therapy, reassess with imaging every 2-3 months 1
• Continue CEA monitoring every 3 months 1

Treatment Sequence

• The patient has already progressed through two standard chemotherapy regimens (FOLFOX and FOLFIRI)
• Third-line therapy options should be considered based on molecular profile and previous treatment tolerance 2, 3

Potential Pitfalls

• Avoid delaying colonoscopy to evaluate the surgical bed finding, as local recurrence requires prompt assessment
• Don't assume all new lesions represent metastatic disease without appropriate evaluation (especially for isolated lesions)
• Remember that bevacizumab (Avastin) can be continued beyond progression with a change in the chemotherapy backbone in selected patients 3

Special Considerations

• Assess patient's performance status before deciding on intensity of next treatment regimen
• Consider cumulative toxicities from previous treatments, particularly neuropathy from oxaliplatin and potential for reintroduction 4
• Evaluate for clinical trial options, especially if standard therapies have been exhausted

The colonoscopy is the immediate next step to evaluate the surgical bed finding, while simultaneously planning for modification of systemic therapy based on disease progression.