What stage is ovarian cancer (Ca ovary) that involves the lumen of the sigmoid colon?

Staging of Ovarian Cancer Involving the Lumen of Sigmoid Colon

Ovarian cancer involving the lumen of the sigmoid colon is classified as stage IIIC according to the FIGO staging system, as it represents histologically proven malignant extension to the small bowel or omentum with peritoneal metastasis beyond the pelvis.

FIGO Staging System for Ovarian Cancer

The International Federation of Gynecology and Obstetrics (FIGO) staging system provides the framework for classifying ovarian cancer:

Stage III Definition

Stage III is defined as "tumor involving one or both ovaries with histologically confirmed peritoneal implants outside the pelvis and/or positive regional lymph nodes. Superficial liver metastasis equals stage III. Tumor is limited to the true pelvis but with histologically proven malignant extension to small bowel or omentum" 1.

Specific Staging for Bowel Involvement

When ovarian cancer involves the sigmoid colon lumen, this represents direct extension of the tumor to other pelvic tissues with histologically verified malignant extension to the bowel. This falls under stage IIIC classification because:

• It involves malignant extension to the small bowel or omentum 1
• It represents peritoneal metastasis beyond the pelvis 1

Clinical Implications of Staging

The staging has significant implications for treatment approach and prognosis:

• Surgical Approach: Requires aggressive cytoreductive surgery including rectosigmoid colon resection to achieve optimal debulking 2
• Chemotherapy: Stage IIIC disease requires carboplatin (AUC 5-7.5) plus paclitaxel (175 mg/m²/3 hours) every 3 weeks for 6 cycles 1
• Prognosis: 5-year overall survival for advanced-stage ovarian cancer (Stage III) is approximately 35-45% 3

Surgical Considerations

Involvement of the sigmoid colon lumen necessitates specific surgical approaches:

• Rectosigmoid colon resection is often required as part of cytoreductive surgery 2
• The goal should be complete cytoreduction with no visible residual disease 3
• Multivariate analysis shows that residual disease after surgery is the strongest predictive factor for recurrence or death 2

Common Pitfalls in Staging

Several important considerations should be noted:

1. Misdiagnosis: Colonic involvement may be misinterpreted as primary colon cancer. Immunohistochemical staining using cytokeratins-7 and -20 can help differentiate ovarian from colonic primary 4

2. Incomplete Staging: Failure to perform adequate surgical staging can lead to understaging. Studies show up to 31% of patients initially assessed as having early-stage disease were upstaged after systematic restaging 1

3. Surgical Approach: Inadequate surgical debulking significantly worsens prognosis. Patients with no macroscopic residual disease have significantly better 2-year survival rates (100%) compared to those with residual disease larger than 1 cm (0% 2-year survival) 2

Treatment Implications

The stage IIIC classification directs specific treatment approaches:

• Primary Treatment: Maximal surgical cytoreduction followed by platinum-based chemotherapy 1
• Surgical Goal: Complete tumor resection with no visible residual disease 3
• Chemotherapy: Standard regimen of carboplatin plus paclitaxel for 6 cycles 1
• Maintenance Therapy: May include bevacizumab and/or PARP inhibitors for eligible patients 5

In conclusion, ovarian cancer with sigmoid colon lumen involvement represents stage IIIC disease, requiring aggressive surgical management with rectosigmoid resection followed by platinum-based chemotherapy to optimize survival outcomes.