Management of Sigmoid Cancer with Bladder Wall Infiltration
For sigmoid colon cancer with bladder wall infiltration (T4b disease), the optimal management is neoadjuvant chemotherapy with FOLFOX-based regimens (with or without bevacizumab) followed by en bloc resection of the sigmoid colon with partial bladder resection when tumor response allows bladder preservation, or total cystectomy if complete bladder invasion persists.
Initial Treatment Strategy
Neoadjuvant Chemotherapy as First-Line Approach
Neoadjuvant chemotherapy should be administered before attempting surgical resection to achieve tumor downstaging and potentially preserve bladder function 1, 2, 3, 4.
The preferred regimens include:
Response assessment with CT imaging should be performed after every 2-4 courses to evaluate tumor reduction and determine surgical feasibility 1, 2, 3.
Rationale for Chemotherapy-First Approach
Neoadjuvant chemotherapy can achieve significant tumor downsizing, converting unresectable disease to resectable with bladder preservation in many cases 2, 3, 4.
This approach improves quality of life by avoiding total cystectomy and urinary diversion when possible 2.
Partial response (PR) rates are achievable, with documented cases showing complete resolution of bladder invasion after chemotherapy 3, 4.
Surgical Management
Timing and Extent of Resection
Surgery should be performed after achieving maximal tumor response, typically after 6-8 courses of chemotherapy 2, 3.
The surgical approach depends on the degree of bladder involvement after neoadjuvant therapy:
En bloc resection of the sigmoid colon and involved bladder segment is mandatory to achieve R0 resection 1, 5.
Additional Surgical Considerations
If abscess formation occurs during chemotherapy (due to tumor necrosis), percutaneous drainage should be performed before definitive surgery 1.
Temporary diverting colostomy may be necessary before initiating chemotherapy in cases with significant obstruction or perforation risk 1, 4.
Combined resection may include abdominal wall if involved, with fascia lata grafting for reconstruction 1.
Postoperative Management
Adjuvant Chemotherapy
Adjuvant chemotherapy with FOLFOX should be administered for 6 courses after curative resection to reduce recurrence risk 3.
This is particularly important for T4b disease given the high risk of systemic relapse.
Key Clinical Pitfalls and Caveats
Diagnostic Considerations
Cystoscopy is essential to confirm bladder invasion and assess the extent of intravesical involvement before treatment planning 3.
Urinalysis showing leukocytes and bacteria suggests colovesical fistula formation, indicating direct bladder invasion 3.
CT and MRI characteristically show a "dumbbell-shaped" tumor protruding into the bladder lumen in cases of diverticular origin 5.
Treatment Sequencing Errors to Avoid
Do not proceed directly to total cystectomy without attempting neoadjuvant chemotherapy unless there is life-threatening hemorrhage or sepsis requiring emergency intervention 2, 3, 4.
Avoid premature surgery before achieving maximal chemotherapy response, as additional courses may further downsize the tumor and improve bladder preservation chances 2, 4.
If switching chemotherapy regimens (e.g., from bevacizumab to panitumumab), ensure adequate response assessment before surgery 4.
Special Circumstances
In cases where sigmoid cancer arises from a colonic diverticulum with bladder involvement, the radiographic appearance may be distinctive, but surgical principles remain the same 5.
If liver metastases are present, they may disappear with chemotherapy, allowing for curative-intent surgery without hepatectomy 2.