Management of Colovesical Fistula in Sigmoid Cancer
En bloc resection of the sigmoid cancer with the involved bladder segment is the definitive treatment for colovesical fistula associated with sigmoid cancer, prioritizing complete tumor clearance to prevent local recurrence and improve survival outcomes.
Surgical Approach
Wide surgical excision is mandatory to achieve tumor clearance, which may require partial or total cystectomy depending on the extent of bladder involvement. 1 The key principle is that inadequate tumor excision leads to bladder recurrence with fatal outcomes in the majority of cases. 1
Standard Operative Strategy
Perform en bloc sigmoid resection with partial cystectomy when bladder invasion is limited and allows for bladder preservation. 2, 3
The resection must include the entire fistula tract and involved bladder segment to achieve R0 resection margins. 4, 3
Consider total cystectomy with urinary diversion when extensive bladder involvement precludes safe partial resection or when tumor clearance cannot be achieved otherwise. 3, 1
A multidisciplinary approach with urologic surgery involvement is essential for optimal outcomes, particularly when complex bladder reconstruction or urinary diversion is required. 1
Role of Neoadjuvant Therapy
Neoadjuvant chemotherapy can enable bladder preservation in select cases by achieving marked tumor regression prior to surgery. 2
In patients where total cystectomy appears necessary at diagnosis, consider neoadjuvant chemotherapy (such as mFOLFOX6 plus panitumumab for appropriate tumor biology) to potentially downstage the tumor and allow partial cystectomy instead. 2
Perform diverting colostomy prior to initiating neoadjuvant therapy to manage fecaluria symptoms and prevent ongoing urinary tract contamination during treatment. 2
Stoma Considerations
Temporary diverting colostomy is often necessary either as part of staged management or for hemodynamically unstable patients. 5
End colostomy (Hartmann procedure) is appropriate for patients with significant comorbidities, hemodynamic instability, or when primary anastomosis is unsafe. 6
Plan stoma location considering the definitive surgical approach and potential need for permanent diversion. 7
Critical Pitfalls to Avoid
Inadequate tumor excision is the primary cause of treatment failure. Three patients in one series who underwent insufficient tumor excision developed bladder recurrence, with two fatal outcomes. 1
Do not attempt bladder-sparing approaches unless neoadjuvant therapy has achieved sufficient tumor regression to ensure clear margins. 2
Ensure complete excision of the fistula tract as residual fistulous tissue can harbor malignant cells. 4, 3
Recognize that colovesical fistula indicates locally advanced disease, requiring aggressive surgical approach rather than limited resection. 4
Reconstructive Options
Bladder reconstruction can be performed at the time of tumor excision when partial cystectomy is feasible, avoiding the need for permanent urinary diversion. 1
Substitution cystoplasty has been successfully performed in select patients undergoing wide excision. 1
The decision for immediate reconstruction versus staged approach depends on the extent of resection, patient stability, and absence of gross contamination. 1
Prognosis
Despite fistula formation indicating advanced disease, wide resection of tumor with the fistula tract and node-bearing areas results in reasonable 5-year survival rates. 4 Aggressive surgical management with complete tumor clearance offers the best chance for cure in this challenging clinical scenario.