Tailoring Treatment for Advanced And/or Recurrent Ovarian Cancer Using the Response of Circulating Tumor Cells to Therapy: A Retrospective Analysis

OBJECTIVE:To examine the role of circulating tumor cell analysis in tailoring therapy for recurrent ovarian cancer by determining the survival outcomes of patients who received circulating tumor cell-guided therapy. METHODS:A retrospective chart review of patients who received circulating tumor cell-guided therapy for recurrent epithelial ovarian cancer at a single center between September 2015 and May 2024. RESULTS:Of 334 records of patients reviewed, 88 patients (26.35%) were referred to circulating tumor cell testing to determine tumor response to therapy and 66 (19.76%) received circulating tumor cell-guided therapy. The median progression-free survival of patients who received circulating tumor cell-guided therapy was significantly longer compared to that of their previous treatment line: 6.70 months (95% confidence interval [CI] 5.30 to 10.80) versus 4.40 months (95% CI 3.77 to 5.83), p = .0042. Twenty-seven patients (55.1%) had a progression-free survival 2/progression-free survival 1 ratio >1.3, suggesting clinical benefit. Patients who received circulating tumor cell-guided therapy had statistically significantly longer median overall survival from circulating tumor cell testing, adjusted for age at diagnosis and stage compared to patients who underwent circulating tumor cell testing but were not treated by circulating tumor cell-guided therapy (13.83 months [95% CI 8.44 to 22.14] versus 2.04 months [95% CI 1.77 to not evaluable], p = .0001). Patients with ≤5 circulating tumor cells expressing epithelial cell adhesion molecule per mL had longer overall survival from circulating tumor cell testing compared to those with >5 epithelial cell adhesion molecule per milliliter. CONCLUSIONS:This retrospective real-world study suggests that circulating tumor cell-guided therapy may enable better disease management, prolonging time on therapy and predicting longer survival after testing. Studies with larger cohorts are necessary to confirm our findings.