Serous Ovarian Cancer Research Articles

Atezolizumab Combined With Platinum and Maintenance Niraparib for Recurrent Ovarian Cancer With a Platinum-Free Interval >6 Months: ENGOT-OV41/GEICO 69-O/ANITA Phase III Trial.

To evaluate atezolizumab combined with platinum-based chemotherapy (CT) followed by maintenance niraparib for late-relapsing recurrent ovarian cancer. The multicenter placebo-controlled double-blind randomized phase III ENGOT-OV41/GEICO 69-O/ANITA trial (ClinicalTrials.gov identifier: NCT03598270) enrolled patients with measurable high-grade serous, endometrioid, or undifferentiated recurrent ovarian cancer who had received one or two previous CT lines (most recent including platinum) and had a treatment-free interval since last platinum (TFIp) of >6 months. Patients were stratified by investigator-selected carboplatin doublet, TFIp, BRCA status, and PD-L1 status in de novo biopsy and randomly assigned 1:1 to receive either atezolizumab or placebo throughout standard therapy comprising six cycles of a carboplatin doublet followed (in patients with response/stable disease) by maintenance niraparib until progression. The primary end point was investigator-assessed progression-free survival (PFS) per RECIST v1.1. Between November 2018 and January 2022, 417 patients were randomly assigned (15% BRCA-mutated, 36% PD-L1-positive, 66% TFIp >12 months, 11% previous poly [ADP-ribose] polymerase inhibitor after frontline CT, and 53% previous bevacizumab). Median follow-up was 28.6 months (95% CI, 26.6 to 30.5 months). Atezolizumab did not significantly improve PFS (hazard ratio, 0.89 [95% CI, 0.71 to 1.10]; P = .28). Median PFS was 11.2 months (95% CI, 10.1 to 12.1 months) with atezolizumab versus 10.1 months (95% CI, 9.2 to 11.2 months) with standard therapy. Subgroup analyses generally showed consistent results, including analyses by PD-L1 status. The objective response rate (ORR) was 45% (95% CI, 39 to 52) with atezolizumab and 43% (95% CI, 36 to 49) with standard therapy. The safety profile was as expected from previous experience of these drugs. Combining atezolizumab with CT and maintenance niraparib for late-relapsing recurrent ovarian cancer did not significantly improve PFS or the ORR.

Mutant p53 Misfolding and Aggregation Precedes Transformation into High-Grade Serous Ovarian Carcinoma.

High Grade Serous Ovarian Cancer (HG-SOC), the most prevalent and aggressive gynecological malignancy, is marked by ubiquitous loss of functional p53, largely due to point mutations that arise very early in carcinogenesis. These mutations often lead to p53 protein misfolding and subsequent aggregation, yet the alterations in intracellular p53 dynamics throughout ovarian cancer progression remain poorly understood. HG-SOC originates from the fallopian tube epithelium, with a well-documented stepwise progression beginning with early pre-malignant p53 signatures. These signatures represent largely normal cells that express and accumulate mutant p53, which then transform into benign serous tubal intraepithelial lesions (STIL), progress into late pre-malignant serous tubal intraepithelial carcinoma (STIC), and ultimately lead to HGSOC. Here, we show that the transition from folded, soluble to aggregated mutant p53 occurs during the malignant transformation of benign precursor lesions into HGSOC. We analyzed fallopian tube tissue collected from ten salpingo-oophorectomy cases and determined the proportion of cells carrying soluble versus mis-folded/mutant p53 through conformation-sensitive staining and quantification. Misfolded p53 protein, prone to aggregation, is present in STICs and HG-SOCs, but notably absent from preneoplastic lesions and surrounding healthy tissue. Overall, our results indicate that aggregation of mutant p53 is a structural defect that distinguishes preneoplastic early lesions from late premalignant and malignant ones, offering a potential treatment window for targeting p53 aggregation and halting ovarian cancer progression.

Protein kinase C iota promotes glycolysis via PI3K/AKT/mTOR signalling in high grade serous ovarian cancer.

Epithelial ovarian cancer, especially high grade serous ovarian cancer (HGSOC) is by far, the most lethal gynecological malignancy with poor prognosis and high relapse rate. Despite of availability of several therapeutic interventions including poly-ADP ribose polymerase (PARP) inhibitors, HGSOC remains unmanageable and identification of early detection biomarkers and therapeutic targets for this lethal malady is highly warranted. Aberrant expression of protein kinase C iota (PKCί) is implicated in many cellular and physiological functions involved in tumorigenesis including cell proliferation and cell cycle deregulation. Two high grade serous ovarian cancer cells SKOV3 and COV362 were employed in this study. PKCί was genetically knocked down or pharmacologically inhibited and several functional and biochemical assays were performed. We report that PKCί is overexpressed in HGSOC cells and patient tissue samples with a significant prognostic value. Pharmacological inhibition of PKCί by Na-aurothiomalate or its shRNA-mediated genetic knockdown suppressed HGSOC cell proliferation, EMT and induced apoptosis. Moreover, PKCί positively regulated GLUT1 and several other glycolytic genes including HK1, HK2, PGK1, ENO1 and LDHA to promote elevated glucose uptake and glycolysis in HGSOC cells. Mechanistically, PKCί drove glycolysis via PI3K/AKT/mTOR signalling. Na-aurothiomalate and highly selective, dual PI3K/mTOR inhibitor dactolisib could serve as novel anti-glycolytic drugs in HGSOC. Taken together, our results indicate PKCί/PI3K/AKT/mTOR signalling cascade could be a novel therapeutic target in a lethal pathology like HGSOC.

Oncolytic adenovirus MEM-288 encoding membrane-stable CD40L and IFNβ induces an anti-tumor immune response in high grade serous ovarian cancer

Single agent immune checkpoint inhibitors have been ineffective for patients with advanced stage and recurrent high grade serous ovarian cancer (HGSOC). Using pre-clinical models of HGSOC, we evaluated the anti-tumor and immune stimulatory effects of an oncolytic adenovirus, MEM-288. This conditionally replicative virus encodes a modified membrane stable CD40L and IFNβ. We demonstrated this virus successfully infects HGSOC cell lines and primary human ascites samples in vitro. We evaluated the anti-tumor and immunostimulatory activity in vivo in immune competent mouse models. Intraperitoneal delivery of MEM-288 decreased ascites and solid tumor burden compared to controls, and treatment generated a systemic anti-tumor immune response. The tumor microenvironment had a higher proportion of anti-tumor macrophages and decreased markers of angiogenesis. MEM-288 is a promising immunotherapy agent in HGSOC, with further pre-clinical studies required to understand the mechanism of action in the peritoneal microenvironment and clinical activity in combination with other therapies.

Evaluation of Serum Proteome Sample Preparation Methods to Support Clinical Proteomics Applications.

Serum contains several proteins that are associated with disease-related processes. Mass spectrometry (MS)-based proteomics approaches greatly facilitate serum protein biomarker development. However, the serum proteome complexity presents a technical challenge for the accurate, sensitive, and reproducible quantification of proteins by MS. Thus, efficient sample preparation methods are of critical importance for serum proteome analyses. In this study, we evaluated the technical performance of two serum proteome sample preparation methods using sera from patients with high-grade serous ovarian cancer and patients with benign nongynecological conditions with a goal of providing insight into their compatibility with clinical proteomics workflows. One method entailed the use of immobilized trypsin (SMART Digest Trypsin) with RapiGest SF, an acid-labile surfactant designed to enhance the in-solution enzymatic digestion of proteins. The other method incorporated a commercially available sample preparation kit, iST-BCT, which contains standardized reagents. Significantly higher protein sequence coverage, albeit with lower digestion efficiency, was obtained with the immobilized trypsin + RapiGest SF workflow, whereas the iST-BCT workflow was quicker and had marginally better reproducibility. Protein relative abundance analysis revealed that the serum proteomes clustered primarily by the sample processing workflow and secondarily by disease state. We conducted a time course study to determine whether differences in the relative abundance of diagnostic high-grade serous ovarian cancer serum protein biomarker candidates were biased according to the duration of enzymatic digestion. Our results highlight the importance of optimizing enzymatic digestion kinetics according to the peptide targets of interest while considering the sensitivity of the downstream analytical method utilized in clinical proteomics workflows designed to measure biomarkers.

Characterization of DNA damage repair pathway utilization in high-grade serous ovarian cancers yields rational therapeutic approaches

While poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) have improved the prognosis of ovarian high-grade serous carcinoma (HGSC) tumors that are homologous recombination (HR) deficient (HRD), new therapeutic strategies are needed for tumors that are HR proficient (HRP) because they demonstrate greater resistance to current treatments and thus have poorer clinical outcomes. Additionally, clinical precautionary statements regarding potential risks associated with PARPi, such as myelodysplastic syndrome, highlight the need for combinatorial approaches that can lessen the dose and duration of PARPi treatment to reduce toxicities. Here, we evaluated DNA double-strand damage repair pathways in HRD and HRP ovarian cancer cell lines and found that in HRD cell lines, PARPi therapy reduced non-homologous end joining (NHEJ)-mediated repair, specifically due to decreased theta-mediated end-joining. The combination of PARPi with ATM serine/threonine kinase inhibitor (ATMi) suppressed both NHEJ and HR pathways in HRD and HRP cell lines, with synergistic increases in apoptosis and decreases in cell viability and colony formation. Interestingly, PARPi plus ATMi also decreased NF-κB p65 phosphorylation, which was not observed when PARPi was combined with inhibition of the ATR kinase (ATRi). These findings indicate that PARPi plus ATMi is a promising strategy for HGSC independent of underlying tumor HR status.

Immune escape between endoplasmic reticulum stress-related cancer cells and exhausted CD8+T cells leads to neoadjuvant chemotherapy resistance in ovarian cancer

Our study aims to explore the effects of neoadjuvant chemotherapy (NACT) on tumour cells and immune cells in the immune microenvironment of patients with high-grade serous ovarian cancer (HGSOC).Single-cell RNA sequencing data of paired ovarian cancer tissues were analysed before and after NACT in 11 patients with HGSOC. The effect of NACT on two major cell components of the tumour microenvironment, epithelial cells and CD8+T cells, was investigated. The mechanisms of epithelial cell evasion by NACT and immune killing were explored from the perspectives of gene expression, functional characteristics, transcriptional regulation, and cell communication. Key targets for reversing NACT resistance were identified and possible therapeutic strategies proposed.While NACT improved the de novo differentiation of anti-tumour CD8+T cells, enhancing their anti-tumour function, it increased the proportion of cancer cells with high HSP90B1 expression. Thus, the potential reasons for NACT resistance were identified as: 1) high levels of endoplasmic reticulum stress (ERS) characteristics, 2) high expression of the MDK-NCL ligand-receptor pair between them and exhausted CD8+T cells before NACT, and 3) high expression of the NECTIN2-TIGIT immune ligand-receptor pair between them and exhausted CD8+T cells after NACT.Thus, our study reveals the mechanisms underlying NACT resistance in patients with HGSOC from the perspective of the independent and interactive roles of cancer cells and CD8+T cells. We propose therapeutic strategies targeting the ERS marker HSP90B1 and the immune escape marker MDK before or during NACT, while targeting NECTIN2 blockade after NACT. This approach may offer new insights into combination treatments for patients with HGSOC displaying NACT resistance.

Development and Validation of a Predictive Model for Resistance to Platinum-Based Chemotherapy in Patients with Ovarian Cancer through Proteomic Analysis.

Platinum resistance in ovarian cancer poses a significant challenge, substantially impacting patient outcomes. Developing an accurate predictive model is crucial for improving clinical decision-making and guiding treatment strategies. Proteomic data from 217 high-grade serous ovarian cancer (HGSOC) biospecimens obtained from JHU, PNNL, and PTRC were used to construct a prediction model for identifying individuals who are resistant to platinum-based chemotherapy. A total of 6437 common proteins were detected across all data sets, with 26 proteins overlapping between the development cohorts JHU and PNNL. Using LASSO and logistic regression analysis, a six-protein model (P31323_PRKAR2B, Q13309_SKP2, Q14997_PSME4, Q6ZRP7_QSOX2, Q7LGA3_HS2ST1, and Q7Z2Z2_EFL1) was developed, which accurately predicted platinum resistance, with an AUC of 0.964 (95% CI, 0.929-0.999). Internal validation by resampling resulted in a C-index of 0.972 (95% CI 0.894-0.988). External validation performed on the PTRC cohort achieved an AUC of 0.855 (95% CI 0.748-0.963). Calibration curves showed good consistency, and DCA indicated superior clinical utility. The model also performed well in predicting PFS and OS at various time points. Based on these proteins, our predictive model can precisely predict platinum response and survival outcomes in HGSOC patients, which can assist clinicians in promptly identifying potentially platinum-resistant individuals.

Platinum-based chemotherapy promotes antigen presenting potential in monocytes of patients with high-grade serous ovarian carcinoma.

Ovarian cancer (OC) is the most lethal gynecologic malignancy worldwide. The major clinical challenge includes the asymptomatic state of the disease, making diagnosis possible only at advanced stages. Another OC complication is the high relapse rate and poor prognosis following the standard first-line treatment with platinum-based chemotherapy. At present, numerous clinical trials are being conducted focusing on immunotherapy in OC; nevertheless, there are still no FDA-approved indications. Personalized decision regarding the immunotherapy, including immune checkpoint blockade and immune cell-based immunotherapies, can depend on the effective antigen presentation required for the cytotoxic immune response. The major aim of our study was to uncover tumor-specific transcriptional and epigenetic changes in peripheral blood monocytes in patients with high-grade serous ovarian cancer (HGSOC). Another key point was to elucidate how chemotherapy can reprogram monocytes and how that relates to changes in other immune subpopulations in the blood. To this end, we performed single-cell RNA sequencing of peripheral blood mononuclear cells (PBMCs) from patients with HGSOC who underwent neoadjuvant chemotherapeutic treatment (NACT) and in treatment-naïve patients. Monocyte cluster was significantly affected by tumor-derived factors as well as by chemotherapeutic treatment. Bioinformatical analysis revealed three distinct monocyte subpopulations within PBMCs based on feature gene expression - CD14.Mn.S100A8.9hi, CD14.Mn.MHC2hi and CD16.Mn subsets. The intriguing result was that NACT induced antigen presentation in monocytes by the transcriptional upregulation of MHC class II molecules, but not by epigenetic changes. Increased MHC class II gene expression was a feature observed across all three monocyte subpopulations after chemotherapy. Our data also demonstrated that chemotherapy inhibited interferon-dependent signaling pathways, but activated some TGFb-related genes. Our results can enable personalized decision regarding the necessity to systemically re-educate immune cells to prime ovarian cancer to respond to anti-cancer therapy or to improve personalized prescription of existing immunotherapy in either combination with chemotherapy or a monotherapy regimen.

Efficacy of PARP inhibitors in advanced high-grade serous ovarian cancer according to BRCA domain mutations and mutation type.

Preclinical studies have emphasized the potential connection between BRCA specific domains defects and the activity of Poly ADP-ribose polymerase inhibitors (PARPi). Nevertheless, real-world evidence regarding the impact of BRCA domain defects and mutations on PARPi efficacy are limited. The aim of his study was to evaluate the efficacy of PARPi in terms of progression free survival (PFS) according to BRCA domains defects and mutation types. A retrospective analysis was performed among 79 BRCA mutated patients, diagnosed with advanced High-grade serous ovarian carcinoma (HGSOC) who received first- and second-line platinum- based chemotherapy followed by PARPi maintenance treatment. PFS was evaluated according to BRCA1 [Really Interesting Gene (RING), DNA Binding (DBD), Serine Cluster (SCD), BRCA1 C-terminal (BRCT)] and BRCA2 [RAD-51 Domain (RAD-51 BD), DBD] specific domain defects and mutation types [missense (MS), nonsense (NS), frameshift (FS), splicing (S), or large rearrangements (LR)]. After a median follow-up of 51 months, no significant difference in PFS was observed between the BRCA functional domains or mutation types in the BRCA1 and BRCA2 subgroups. Patients with BRCA2 DBD and RAD51-BD defects had the longest (39.8 months) and shortest (24.1 months) median PFS, respectively (p = 0.11). Additionally, patients with BRCA1 DBD defects had the greatest benefit (median PFS = 33.8 months) while those with BRCA1 RING domain mutations experienced the worst outcome (median PFS = 30.9 months (p = 0.43). The efficacy of maintenance treatment with PARPi is independent by BRCA domain defects or mutation types. Patients DBD domain defects experienced numerically longer median PFS compared to those with other BRCA1/2 alterations.

Immunohistochemical parameters of serous ovarian carcinomas and possible mechanism of development of resistance to platinum-based drugs

The aim of the study was to evaluate a prognostic significance of immunohistochemical parameters in serous ovarian carcinomas and their statistical relationships after neoadjuvant treatment to assess the development of tumor resistance to platinum-containing adjuvant polychemotherapy regimens. Material and Methods. An immunohistochemical study of tumor tissue was carried out in patients with high-grade serous ovarian cancer (stage IIIC–IV). The age of the patients ranged from 49–72 years. There were 59 patients who were sensitive and 22 patients who were resistant to platinum-containing adjuvant polychemotherapy. In the tissue of ovarian tumors obtained during surgery after noadjuvant polychemotherapy, we studied immunohistochemical indicators of proliferative activity (Ki67), expression of the DNA excision repair protein ERCC1 and proteins of the ABC transporter family – Pgp and BCRP, as well as statistical relationships between these indicators (Spearman’s rank correlation coefficient). Results. After effective neoadjuvant polychemotherapy, more pronounced signs of activity in the processes of proliferation, DNA repair and xenobiotic efflux were noted in serous ovarian carcinomas, which subsequently demonstrated resistance to platinum-containing polychemotherapy regimens compared to tumors that retained platinum sensitivity. Moreover, in 40 % of cases or more, there was a coincidence in the ranges of values of the studied parameters in tumors with different sensitivity to platinum drugs. The expression of transporter proteins greater than 60 % for BCRP and 65 % for Pgp was shown to precede the development of resistance to adjuvant treatment with carboplatin. In the studied groups, differences in the number and significance of statistical relationships between the variables were observed. The most significant differences were noted for the Ki67 – BCRP correlation, which had the opposite direction in groups with different sensitivity to adjuvant treatment with carboplatin. Conclusion. A comprehensive immunohistochemical analysis of highgrade serous ovarian carcinomas after neoadjuvant polychemotherapy, which further demonstrated different sensitivity to platinum-containing adjuvant regimens, was carried out, and the prognostic value of the studied parameters was assessed. The revealed critical levels of Pgp and BCRP expression in tumor tissue may have a prognostic value regarding the effect of adjuvant polychemotherapy. The results of the correlation analysis suggest a relationship between the development of platinum resistance and changes in the nature of the regulatory relationships between proliferative activity and transport processes in tumor tissue.

Biomarker-driven targeted therapy in patients with recurrent platinum-resistant epithelial ovarian cancer (BRIGHT): protocol for an open-label, multicenter, umbrella study

BackgroundPlatinum-resistant, recurrent ovarian cancer has an abysmal prognosis with limited treatment options. Poly-(ADP-ribose)-polymerase (PARP), angiogenesis, and immune checkpoint inhibitors might improve the outcomes of platinum-resistant, recurrent ovarian cancer, but accurate...

Comparative Analysis of Gene Expression Profiles in Ovarian Clear Cell Carcinoma and High-Grade Serous Ovarian Cancer.

To evaluate disparities in gene expression profiles between Ovarian Clear Cell Carcinoma (OCCC) and High-Grade Serous Ovarian Carcinoma (HGSOC). A descriptive study. Place and Duration of the Study: The Second People's Hospital of Jingdezhen, Jiangxi, China, between 31st December 2017 and December 2023. Basic and clinical diagnostic information, along with genetic test reports, were compiled from all patients within the included groups. Differential gene expression between the two cohorts was scrutinised to elucidate its clinical significance. Comparative analysis revealed nine differentially expressed genes in OCCC relative to HGSOC, with six exhibiting significant disparities (p <0.05). These genes are implicated in pivotal cellular processes including the cell cycle, apoptosis, DNA damage repair, and the PI3K pathway. Notably, aberrant expression patterns, such as overexpression of MET and downregulation of PTEN and SMARCA4, correlated with adverse prognosis and survival outcomes in selected patients. Distinctive gene expression profiles between OCCC and HGSOC underscore disparate tumorigenic mechanisms, thereby laying a foundation for the tailored therapeutic interventions. Further elucidation of the identified differentially expressed genes is warranted to delineate their role in OCCC pathogenesis and prognostic significance. Ovarian clear cell carcinoma, High-grade serous ovarian cancer, Gene expression profiles, Homologous recombination repair.

775P Association between chemotherapy response score (CRS) and tumour homologous recombination deficiency (tHRD) in women with newly diagnosed FIGO stage IIIC/IV high-grade serous ovarian cancer (HGSOC)

775P Association between chemotherapy response score (CRS) and tumour homologous recombination deficiency (tHRD) in women with newly diagnosed FIGO stage IIIC/IV high-grade serous ovarian cancer (HGSOC)

779P Testing unselected women with newly diagnosed high-grade serous ovarian cancer (HGSOC) for germline pathogenic variants (PVs) in mismatch repair (MMR) genes is unnecessary

779P Testing unselected women with newly diagnosed high-grade serous ovarian cancer (HGSOC) for germline pathogenic variants (PVs) in mismatch repair (MMR) genes is unnecessary

761P Anti-angiogenic therapy in first-line treatment of low-grade serous ovarian cancer: Exploratory meta-analysis of the prospective AGO-OVAR 11/12/16 studies

761P Anti-angiogenic therapy in first-line treatment of low-grade serous ovarian cancer: Exploratory meta-analysis of the prospective AGO-OVAR 11/12/16 studies

Colocalization of Cancer-Associated Biomarkers on Single Extracellular Vesicles for Early Detection of Cancer

Detection of cancer early, when it is most treatable, remains a significant challenge due to the lack of diagnostic methods sufficiently sensitive to detect nascent tumors. Early-stage tumors are small relative to their tissue of origin, heterogeneous, and infrequently manifest in clinical symptoms. Detection of their presence is made more difficult by a lack of abundant tumor-specific indicators (i.e., protein biomarkers, circulating tumor DNA, etc.) that would enable detection using a non-invasive diagnostic assay. To overcome these obstacles, we have developed a liquid biopsy assay that interrogates circulating extracellular vesicles (EVs) to detect tumor-specific biomarkers colocalized on the surface of individual EVs. We demonstrate the technical feasibility of this approach in human cancer cell line-derived EVs where we show strong correlations between assay signal and cell line gene/protein expression for the ovarian cancer-associated biomarkers BST2, FOLR1, and MUC1. Furthermore, we demonstrate that detecting distinct colocalized biomarkers on the surface of EVs significantly improves discrimination performance relative to single biomarker measurements. Using this approach, we observe promising discrimination of high-grade serous ovarian cancer versus benign ovarian masses and healthy women in a proof-of-concept clinical study.

776P Liquid biopsy for the determination of homologous recombination deficiency in patients with high-grade serous ovarian cancer: Results of the BOVARY-pilot study

776P Liquid biopsy for the determination of homologous recombination deficiency in patients with high-grade serous ovarian cancer: Results of the BOVARY-pilot study

Patient-derived ovarian cancer organoid carries immune microenvironment and blood vessel keeping high response to cisplatin.

Ovarian cancer is high recurrence and mortality malignant tumor. The most common ovarian cancer was High-Grade Serous Ovarian Cancer. However, High-Grade Serous Ovarian Cancer organoid is rare, which organoid with patient immune microenvironment and blood vessels even absence. Here, we report a novel High-Grade Serous Ovarian Cancer organoid system derived from patient ovarian cancer samples. These organoids recapitulate High-Grade Serous Ovarian Cancer organoids' histological and molecular heterogeneity while preserving the critical immune microenvironment and blood vessels, as evidenced by the presence of CD34 + endothelial cells. Whole exome sequencing identifies key mutations (CSMD3, TP53, GABRA6). Organoids show promise in testing cisplatin sensitivity for patients resistant to carboplatin and paclitaxel, with notable responses in cancer proteoglycans and p53 (TP53) signaling, like ACTG/ACTB1/AKT2 genes and BBC3/MDM2/PERP. Integration of immune microenvironment and blood vessels enhances potential for novel therapies like immunotherapies and angiogenesis inhibitors. Our work may provide a new detection system and theoretical basis for ovarian cancer research and individual therapy.

The Impact of Liquid Biopsy in Advanced Ovarian Cancer Care.

Ovarian cancer is the third most common gynaecological cancer and has a very high mortality rate. The cornerstone of treatment is complete debulking surgery plus chemotherapy. Even with treatment, 80% of patients have a recurrence. Circulating tumour DNA (ctDNA) has been shown to be useful in the control and follow-up of some tumours. It could be an option to define complete cytoreduction and for the early diagnosis of recurrence. We aimed to demonstrate the usefulness of ctDNA and cell-free DNA (cfDNA) as a marker of complete cytoreduction and during follow-up in patients with advanced ovarian cancer. We selected 22 women diagnosed with advanced high-grade serous ovarian cancer, of which only 4 had complete records. We detected cfDNA by polymerase chain reaction (PCR), presented as ng/mL, and detected ctDNA with droplet digital PCR (ddPCR). We calculated Pearson correlation coefficients to evaluate correlations among cfDNA, ctDNA, and cancer antigen 125 (CA125), a biomarker. The results obtained in the evaluation of cfDNA and ctDNA and their correlation with tumour markers and the radiology of patients with complete follow-up show disease progression during the disease, stable disease, or signs of recurrence. cfDNA and ctDNA correlated significantly with CA125. Following cfDNA and ctDNA over time indicated a recurrence several months earlier than computed tomography and CA125 changes. An analysis of cfDNA and ctDNA offers a non-invasive clinical tool for monitoring the primary tumour to establish a complete cytoreduction and to diagnose recurrence early.