This retrospective cohort study investigates the predictive utility of PET/CT versus diagnostic laparoscopy for complete, optimal and suboptimal surgical resection in the reassessment phase for women after three cycles of neoadjuvant chemotherapy (NACT) in the treatment of advanced stage (FIGO IIIC/IVB) epithelial ovarian cancer where primary debulking surgery (PDS) was not deemed feasible. In our tertiary gynae-oncology unit we perform 15-20 interval debulking surgeries (IDS) for women with advanced ovarian cancer annually. At our centre all women with advanced stage epithelial ovarian cancer undergo PET/CT, multidisciplinary review and diagnostic laparoscopy prior to laparotomy for IDS.
Phase III randomised controlled trials EORTC 55971, SCORPION and CHORUS have demonstrated non-inferior survival rates, and lower peri-operative morbidity and mortality for women undergoing NACT and IDS when compared with PDS and adjuvant chemotherapy (1). The non-inferior survival outcomes are only present when resection of tumour is complete or optimal (less than one centimetre macroscopic residual tumour). Recent retrospective studies have also shown an adverse effect on overall survival (OS) and progression free survival (PFS) with greater time interval from last NACT cycle and IDS (2, 3). As ovarian cancer remains the most lethal gynaecological malignancy in developed nations, timely and accurate assessment of tumor resectability is a high priority.
To date, the ability of PET/CT to discriminate and reliably predict complete and optimal surgical resection has not been assessed in the group of women undergoing IDS. PET/CT has shown similar sensitivity but greater specificity when compared to CT in prediction of optimal resection for PDS (4). PET/CT does not reach the sensitivity and specificity of diagnostic laparoscopy in women being assessed for PDS (4). To date no study has compared PET/CT to diagnostic laparoscopy in the sub-group of women undergoing assessment for IDS. The Suidan criteria have been used to assess PET/CT in prediction of utility versus futility of PDS (5, 6). The Suidan criteria include clinical and radiological criteria. Clinical criteria include Ca125 level greater than 500 units per millilitre, age greater than or equal to 60 years and ASA score 3-4. Radiological criteria include suprarenal retroperitoneal lymph node metastasis, diffuse small bowel thickening and/or adhesions, small bowel mesenteric metastasis greater than one centimetre, metastasis involving the root of the superior mesenteric artery, perisplenic area and lesser sac (5). Suidan criteria in PET/CT have demonstrated predictive value in optimal PDS (6).
Over the period of January 2017 to December 2022, we have collected clinical and demographic data including age, BMI, co-morbidity, index and interval Ca125 level. Radiologic studies are being reviewed and reassessed according to the Suidan criteria to confirm or refute the ability of PET/CT to effectively predict optimal or suboptimal IDS. Our data collection and radiological assessment is due for completion in November 2023 and data analysis will be completed in January 2024 with the goal of demonstrating the utility of PET/CT when compared with diagnostic laparoscopy for women undergoing IDS for advanced ovarian cancer.
1. Eggink, F. A., et al. (2017). "Surgery for patients with newly diagnosed advanced ovarian cancer: Which patient, when and extent?" Current Opinion in Oncology 29(5) https://oadoi.org/10.1097/CCO.0000000000000387
2. Lee, J. L., et al. (2018). "Impact of the time interval from completion of neoadjuvant chemotherapy to initiation of postoperative adjuvant chemotherapy on the survival of patients with advanced ovarian cancer." Gynecologic Oncology 148(1) https://doi.org/10.1016/j.ygyno.2017.11.023
3. Andrikopoulou, A., et al. (2023). "Optimal Time Interval between Neoadjuvant Platinum-Based Chemotherapy and Interval Debulking Surgery in High-Grade Serous Ovarian Cancer.” Cancers 15(13) https://doi.org/10.3390/cancers15133519
4. Roze, J.F., et al. (2018). "Positron emission tomography (PET) and magnetic resonance imaging (MRI) for assessing tumour respectability in advanced epithelial ovarian/Fallopian tube/primary peritoneal cancer."Cochrane Database of Systematic Reviews 2018 10 https://doi.org/10.1002/14651858.CD012567.pub2
5. Suidan, R.S., et al. (2014). "A multi centre prospective tria evaluating the ability of preoperative computed tomography scan and serum CA-125 to predict suboptimal cytoreduciton at primary debulking surgery for advanced ovarian, Fallopian tube, and peritoneal cancer." Gynecologic Oncology 134(3) https://doi.org/10.1016/j.ygyno.2014.07.002
6. Wang, J., et al. (2022). "Preoperative PET?CT score can predict incomplete resection after debulking surgery for advanced serous ovarian cancer better than CT score, MTV, tumour markers and haematological markers." Acta Obstetric et Gynecolgoica Scandinavica 101(11) https://doi.org/10.1111/aogs.14442