Initial Treatment for Infiltrating Colon Adenocarcinoma
Surgery is the main treatment for infiltrating colon adenocarcinoma, with the addition of complementary or adjuvant treatment as appropriate based on disease stage. 1
Surgical Approach
- En bloc colonic and mesenteric resection with wide margins (at least 5 cm on either side of tumor) is the standard surgical approach 2
- At least 12 lymph nodes must be examined to accurately define stage II vs. III disease 2
- Laparoscopic colectomy is a valid alternative to open surgery when technical expertise is available, offering:
- Reduced morbidity
- Improved tolerance
- Similar oncological outcomes compared to open surgery 2
Treatment Algorithm Based on Disease Stage
Stage I (T1-2, N0)
- Surgery alone is curative with no indication for adjuvant treatment 1, 2
- For T1N0M0 with low-risk features, local excision may be considered 2
- For T1N0M0 with high-risk features, standard resection is required 2
Stage II (T3-4, N0)
- Surgery is the primary treatment
- Adjuvant chemotherapy may be considered in high-risk stage II patients with the following features 1, 2:
- T4 tumors
- Poorly differentiated histology
- Vascular/lymphatic/perineural invasion
- Obstruction or perforation at presentation
- Fewer than 12 lymph nodes examined
- High CEA level
Stage III (Any T, N1-2)
- Surgery followed by adjuvant chemotherapy is the standard of care 1, 2
- Oxaliplatin-based regimens (FOLFOX or CAPOX) are the preferred adjuvant treatment 2, 3
- For patients who cannot tolerate oxaliplatin, fluoropyrimidine monotherapy (5-FU/LV or capecitabine) is recommended 2
Stage IV (Any T, Any N, M1)
- Treatment strategy depends on resectability of metastases:
- For resectable metastases: Surgery of primary tumor and metastases, with perioperative chemotherapy 1
- For potentially resectable metastases: Most active induction chemotherapy followed by surgery if metastases become resectable 1
- For unresectable metastases: Palliative chemotherapy with 5-FU-based regimens, potentially combined with oxaliplatin or irinotecan 1
Timing and Duration of Adjuvant Therapy
- Adjuvant chemotherapy should be started as early as possible, ideally 3-8 weeks after surgery and no later than 12 weeks 1
- Standard duration is 6 months for adjuvant chemotherapy 1, 4
- Recent evidence suggests 3 months of CAPOX may be sufficient for low-risk stage III disease 5
Special Considerations
- MMR/MSI status should be evaluated before starting therapy, especially in stage II patients 2
- DPD genotype or phenotype should be determined before starting fluoropyrimidine therapy 2
- For obstructive colon cancer, local obstruction relief (stent placement, colostomy, or primary lesion resection) should be performed before systemic therapy 1
- In synchronous metastatic disease, the order of surgical resection (simultaneous vs. staged) depends on patient condition and comprehensive assessment of surgical safety 1
Common Pitfalls to Avoid
- Delaying adjuvant chemotherapy beyond 12 weeks after surgery significantly reduces efficacy 2
- Examining fewer than 12 lymph nodes can lead to understaging and inappropriate treatment decisions 2
- Failure to complete colonoscopy of the entire colon may miss synchronous lesions 2
- Not considering patient factors like age, comorbidities, and performance status when selecting adjuvant therapy regimens 1
By following this treatment algorithm, patients with infiltrating colon adenocarcinoma can receive optimal care that maximizes survival outcomes while maintaining quality of life.