CA-125 KELIM Score May Predict Efficacy in Patients With Epithelial Ovarian Cancer Receiving HIPEC During Surgery

Gabriella Smith, MD

CA-125 ELIMination Rate Constant K (KELIM) score was found to be predictive of progression-free survival (PFS) and overall survival (OS) outcomes for patients with epithelial ovarian cancer undergoing hyperthermic intraperitoneal chemotherapy (HIPEC) at the time of surgery, signaling its potential utility as a tool for identifying patients who would derive the most benefit from this therapeutic approach, according to data from a retrospective, single-institution study.

Gabriella Smith, MD, and colleagues shared the data in a poster presentation at the SGO 2024 Winter Meeting. It was found that patients with a favorable KELIM score of 1 or greater had a longer median PFS of 19.7 months vs a median PFS of 12.3 months in patients with an unfavorable score of less than 1.

Furthermore, the median OS was not reached in patients with a favorable KELIM score, who exhibited a 3-year OS rate of 79.9% (95% CI, 65.5-94.4). Conversely, patients with an unfavorable score had an OS rate of 43.6% (95% CI, 20.9-66.4). The median follow-up duration for all patients was 29.9 months (95% CI, 16.3-38.0), with a median PFS of 15.2 months and a median OS of 39.1 months.

“Although it is a small, retrospective analysis, these data demonstrate that the KELIM score can be a prognostic indicator for patients who are undergoing neoadjuvant chemotherapy and are going to have HIPEC at their interval debulking surgery, which is consistent with previous studies analyzing this [kinetic parameter],” said Smith, who is an obstetrician/gynecologist at the Cleveland Clinic in Cleveland, Ohio.

In an interview with OncLive^®, Smith discussed background data providing the rationale for this study, detailed the specific patient population that was evaluated and what methods were utilized to examine this population, and expanded on the potential impact of CA-125 KELIM’s predictive value for patients with epithelial ovarian cancer.

OncLive: What prior research supported the inception of this which assessed the predictive value of KELIM scores during interval debulking surgery in epithelial ovarian cancer?

Smith: The KELIM score was validated by a study looking at the use of the score to predict PFS and OS in patients undergoing neoadjuvant chemotherapy prior to interval debulking surgery. We wanted to see if those findings were consistent for patients who also underwent HIPEC at the time of their interval debulking surgery. We chose patients who had high-grade serous ovarian cancer because the KELIM score [has been] validated in that population.

We then looked at PFS and OS for patients who are undergoing HIPEC at the time of their interval debulking. The use of HIPEC varies among regions and institutions, but we have a robust program at the Cleveland Clinic. For patients who are undergoing interval debulking surgery, meet the [prespecified] criteria, and are open to HIPEC, we offer that as a treatment option.

Please give a brief overview of this study, including its methodology and enrollment criteria.

This was a single-institution, retrospective study from our HIPEC database that has been recording patients that we perform HIPEC on. We looked at patients from 2017 to 2022 with advanced high-grade serous ovarian cancer who underwent neoadjuvant chemotherapy followed by HIPEC during interval cytoreductive surgery. Patients had to have at least 3 CA-125 levels within 100 days of initiating neoadjuvant chemotherapy to be able to calculate the KELIM score. If they didn’t have that, we couldn’t calculate it and they were excluded. We also excluded patients who had a non-high grade serous histology, as well as patients who were lost to follow-up. Sometimes we get patients who are referred to us specifically for interval debulking and HIPEC, but we don’t give them their neoadjuvant or their adjuvant therapy. Those patients were not included because we wouldn’t have access to their follow-up data.

We calculated PFS and OS using the Cox univariate and multivariate regression. However, the number of events in the multivariate regression were too low for that to be meaningful, so most of the data presented were from the univariate analyses.

We had a total of 63 patients in our analysis. Age, BRCA status, the number of neoadjuvant cycles of chemotherapy and responses to chemotherapy were relatively balanced between the groups. The 1 significant difference between the 2 groups is that patients who had a more favorable KELIM score of 1 or greater, tended to have [a decreased incidence of] radical hysterectomies.

Overall, the [frequency of] other cytoreductive procedures were [comparable] between groups. [There was a] relatively non-statistically significant difference between post-operation severity complications and residual disease at the time of surgery.

What key findings were presented during the meeting?

We found that patients who had a favorable KELIM score had a higher PFS, and the median follow-up duration was approximately 30 months for all patients. Median PFS for the [favorable] KELIM group was 19.7 months vs 12.3 months. OS was not reached in our favorable KELIM group, [but 3-year OS rates were] higher at 79.9% compared with 43.6% in patients with an unfavorable KELIM score. Based on the background data, we were anticipating these results.

What next steps are planned for this research and what would you like your colleagues to take away from this presentation?

We need more patients and [data] to have a more robust dataset; however, the next step [is to compare] the KELIM score in patients who receive HIPEC at the time of interval debulking vs patients who don’t receive HIPEC at this time. As more data become available, [we may see] that the KELIM score can be a great tool to [identify which patients] may be an ideal candidate for interval debulking or HIPEC. We don’t have the data yet to definitively [support its use], but it’s something exciting that [could] become part of our [toolkit] when we try to select the ideal candidates for HIPEC.

Reference

Smith, G, Kelley J, Yao M, et al. CA-125 KELIM score predicts progression free and overall survival in patients with epithelial ovarian cancer undergoing HIPEC at time of interval cytoreductive surgery. Presented at: SGO 2024 Winter Meeting. January 25-27, 2024; Olympic Valley, California. Abstract 1.