Cytoreductive Surgery for Recurrent Ovarian Cancer

• Overall Survival (OS): The median OS was 53.7 months in the surgery arm compared to 46.0 months in the non-surgery arm (Hazard Ratio [HR] 0.75; $p = 0.02$).
• Progression-Free Survival (PFS): The median PFS was significantly improved at 18.4 months versus 14.0 months ($p < 0.001$).

The SOC-1 Trial: Supporting PFS Benefits

The SGOG SOC-1 trial, conducted in academic centers in China, also provided support for surgery, specifically regarding disease control. Using the iMODEL selection criteria, the trial showed a significant improvement in Progression-Free Survival (PFS), with a median of 17.4 months in the surgery group compared to 11.9 months in the non-surgery group ($p < 0.001$). However, at the time of reporting, the overall survival data remained immature.

The GOG-213 Trial: The Outlier

In contrast to the positive findings of DESKTOP III and SOC-1, the GOG-213 trial did not show a significant benefit in either OS or PFS. Several factors may explain this discrepancy:

1. Study Design: GOG-213 included two studies in one, involving Bevacizumab (an anti-angiogenic agent).
2. Selection Criteria: Unlike the highly selective AGO or iMODEL approaches, GOG-213 used more individualized selection.
3. The Bevacizumab Factor: There is a clinical question of whether the use of Bevacizumab might "replace" the impact of surgery or if surgery becomes less beneficial when such potent systemic agents are used.

Exam Tip: When comparing these trials, remember that DESKTOP III and SOC-1 used rigorous, model-based pre-operative selection (AGO Score and iMODEL, respectively), whereas GOG-213 had a more heterogeneous population and included Bevacizumab, which may have masked the surgical benefit.

Precision Patient Selection: AGO Score and iMODEL

To avoid the pitfalls seen in trials like GOG-213, clinicians use predictive models to identify patients most likely to benefit from surgery.

The AGO Score

Developed through the DESKTOP I and II studies, the AGO Score is used to predict the likelihood of achieving complete gross resection (CGR). A patient is considered "AGO Score positive" if they meet all three of the following criteria:

• ECOG performance status = 0 (excellent functional status).
• No residual disease after primary surgery (or initially FIGO stage I/II).
• Absence of ascites (defined as $< 500\text{ mL}$).

The iMODEL Selection Criteria

The iMODEL is a more complex scoring system derived from pooled analyses of retrospective studies. It considers a broader range of impact factors to predict resectability:

• FIGO stage (I/II vs. III/IV)
• Residual disease (RD) after primary surgery
• Platinum-free interval (PFI) (longer intervals, $\ge 16$ months, are more favorable)
• ECOG performance status (0–1 is ideal)
• CA125 levels at recurrence ($\le 105\text{ U/ml}$ is more favorable)
• Presence of ascites (absence is more favorable)

Clinical Decision Making

The decision to offer secondary cytoreduction should be individualized but guided by the patient's disease biology. Generally, ideal candidates are those with platinum-sensitive disease—defined as a recurrence occurring more than six months after the completion of adjuvant platinum-based chemotherapy.

Patients with an early recurrence (platinum-resistant disease) often show a decreased response to additional chemotherapy and are generally not considered ideal candidates for secondary cytoreduction.

Summary Table: Selection Logic

Conclusion

While not all clinical trials have yielded positive results, the weight of evidence from validated, prospective studies like DESKTOP III suggests that cytoreductive surgery provides a significant survival benefit when applied to the right patients. The key to success lies in careful patient selection using tools like the AGO Score or iMODEL and ensuring that surgery is performed in competent centers where it can be integrated with subsequent platinum-based chemotherapy.