Yoo-Na Kim

Serial Circulating Tumor DNA Analysis with a Tumor-Naïve Next-Generation Sequencing Panel Detects Minimal Residual Disease and Predicts Outcome in Ovarian Cancer

Abstract Circulating tumor DNA (ctDNA) may aid in personalizing ovarian cancer therapeutic options. Here, we aimed to assess the clinical utility of serial ctDNA testing using tumor-naïve, small-sized next-generation sequencing (NGS) panels. A total of 296 patients, including 201 with ovarian cancer and 95 with benign or borderline disease, were enrolled. Samples were collected at baseline (initial diagnosis or surgery) and every 3 months after that, resulting in a total of 811 blood samples. Patients received adjuvant therapy based on the current standard of care. Cell-free DNA was extracted and sequenced using an NGS panel of 9 genes: TP53, BRCA1, BRCA2, ARID1A, CCNE1, KRAS, MYC, PIK3CA, and PTEN. Pathogenic somatic mutations were identified in 69.2% (139/201) of patients with ovarian cancer at baseline but not in those with benign or borderline disease. Detection of ctDNA at baseline and/or at 6 months follow-up was predictive of progression-free survival (PFS). PFS was significantly poorer in patients with detectable pathogenic mutations at baseline that persisted at follow-up than in patients that converted from having detectable ctDNA at baseline to being undetectable at follow-up; survival did not differ between patients without pathogenic ctDNA mutations in baseline or follow-up samples and those that converted from ctDNA positive to negative. Disease recurrence was also detected earlier with ctDNA than with conventional radiologic assessment or CA125 monitoring. These findings demonstrate that serial ctDNA testing could effectively monitor patients and detect minimal residual disease, facilitating early detection of disease progression and tailoring of adjuvant therapies for ovarian cancer treatment. Significance: In ovarian cancer, serial circulating tumor DNA testing is a highly predictive marker of patient survival, with a significantly improved recurrence detection lead time compared with conventional monitoring tools.

Genomic Profiling in Patients with Endometrial Cancer by Deep Sequencing of Vaginal Swabs and Plasma

Abstract Purpose: Endometrial cancer is a common gynecologic malignancy that lacks effective noninvasive screening tools as traditional approaches rely on invasive biopsies. In this large prospective study, we evaluated a novel approach combining vaginal swab DNA and plasma-based ctDNA for genomic profiling to provide a comprehensive framework for diagnosis, prognosis, and disease monitoring. Experimental Design: Adult patients with diverse stages of endometrial cancer, preneoplastic disease, and benign endometrial conditions were prospectively recruited over 2 years. Paired vaginal swab DNA and plasma-based ctDNA were collected preoperatively, and additional plasma samples were obtained at multiple time points postoperatively. Deep next-generation sequencing targeting 101 genes was performed, achieving an average depth exceeding 40,000×. Results: A total of 191 patients contributed 388 samples. Vaginal swab DNA demonstrated 77.7% sensitivity and 96.6% specificity. PTEN mutations were associated with favorable prognosis (HR: 0.27; 95% confidence interval, 0.092–0.77), and TP53 mutations were associated with poor prognosis (HR: 3.7; 95% confidence interval, 1.4–10). A novel classification system based on the mutational profile of PTEN/TP53 identified distinct prognostic groups. Plasma-based ctDNA was significantly associated with stage, lymphovascular invasion, and prognosis (P < 0.01 for all). Patients with preoperative positive plasma-based ctDNA results exhibited poorer outcomes (P < 0.01), whereas postoperative positive ctDNA results enabled early detection of recurrence. Conclusions: These two noninvasive methods play distinct, complementary roles in the management of endometrial cancer. Vaginal swab DNA and novel PTEN/TP53-based classification have distinct prognostic advantages over existing frameworks. Plasma-based ctDNA provides dynamic insights into recurrence risk and disease progression.

Comparison of progression-free survival outcome of sentinel node biopsy without ultrastaging versus lymphadenectomy in endometrial cancer: a propensity-matched analysis

We aimed to investigate the oncologic outcomes of patients with endometrial cancer who underwent sentinel lymph node (SLN) biopsy without ultrastaging compared with that of those who underwent lymphadenectomy (LND). Patients with endometrial cancer who underwent staging with SLN biopsy or LND during 2006 - 2021 were analyzed using propensity score matching (PSM). SLN metastasis was examined using hematoxylin and eosin staining, without ultrastaging. Progression-free survival (PFS) was compared between the two groups before and after PSM using age, histology, and stage as covariates. Clinical variables such as recurrence patterns and lymphatic complications, were assessed. After excluding 213 patients who underwent validation LND with SLN biopsy, 902 were identified. The demographics of the remaining patients differed according to histology, myometrial invasion depth, and stage. Lymph node metastasis was less frequent in the SLN group than in the LND group (9.4% vs. 3.8%, p=0.004). The recurrence rates within 2 years were lower in the SLN group. The SLN group exhibited significantly superior 2-year and overall PFS than the LND group. Among patients with uterus-confined disease, overall PFS was favorable for SLN biopsy. After matching, differences in PFS were no longer observed, although the lymphocele and lymphedema rates were significantly lower in the SLN group. In patients with endometrial cancer, SLN biopsy without ultrastaging did not compromise survival outcomes and was associated with significantly reduced lymphatic complication rates compared with LND. Therefore, SLN biopsy can be recommended for patients with endometrial cancer without definitive preoperative evidence of distant metastasis.

Comparison of outcomes between the one-step and two-step sentinel lymph node mapping techniques in endometrial cancer

Fluorescence image-guided sentinel lymph node (SLN) biopsy using a two-step mapping technique incorporates sequential injection of indocyanine green into the bilateral uterine cornus, followed by cervical injection. Outcomes were compared with the conventional cervical (one-step) method . Patients with FIGO stage I-III endometrial cancer who underwent laparoscopic or robotic staging, including SLN biopsy, from May 2014 to December 2018, were retrospectively reviewed. Patient characteristics, pre-operative imaging, SLN detection pattern, pathologic result, adjuvant, and recurrence locations were analyzed. A total of 199 patients received one-step (n=123) and two-step (n=76) SLN biopsy. Para-aortic SLN were more frequently identified in the two-step group. Lower and upper para-aortic SLN were identified in 67.1% and 38.2%, respectively, in the two-step group and in 18.7% and 5.7% in the one-step group (p<0.001). The number of para-aortic SLN harvested was superior in the two-step group (p<0.001). Metastatic para-aortic SLN were found in 7.9% of the two-step group and 2.4% of the one-step group (p=0.070). In detecting nodal metastasis, the sensitivities of the one- and two-step methods were 91.7% and 100.0%, negative predictive values were 99.0% and 100.0%, false-negative rates were 8.3% and 0%, and accuracy rates were 99.1% and 100.0%, respectively. The one-step method identified only three out of eight para-aortic lymph node metastases and missed five para-aortic lymph node metastases. There was no missed para-aortic lymph node metastasis in the two-step group. Recurrence was observed in two patients (2.6%; vaginal vault and adrenal gland) in the two-step group and seven patients (5.7%) including three nodal recurrences in the one-step group (p=0.307). Two-step SLN mapping improved the para-aortic SLN detection rate, a known pitfall of conventional cervical injection. Proper evaluation of aortic nodal status will assist in the tailoring of adjuvant and prevent undertreatment of patients with isolated para-aortic metastasis.

RAD51/geminin/γH2AX immunohistochemical expression predicts platinum-based chemotherapy response in ovarian high-grade serous carcinoma

The RAD51 assay is a recently developed functional assay for homologous recombination deficiency (HRD) that reflects real-time HRD status. We aimed to identify the applicability and predictive value of RAD51 immunohistochemical expression in pre- and post-neoadjuvant chemotherapy (NAC) samples of ovarian high-grade serous carcinoma (HGSC). We evaluated the immunohistochemical expression of RAD51/geminin/γH2AX in ovarian HGSC before and after NAC. In pre-NAC tumors (n=51), 74.5% (39/51) showed at least 25% of γH2AX-positive tumor cells, suggesting endogenous DNA damage. The RAD51-high group (41.0%, 16/39) showed significantly worse progression-free survival (PFS) compared to the RAD51-low group (51.3%, 20/39) (p High RAD51 expression was significantly associated with worse PFS in HGSC, and post-NAC RAD51 status showed higher association than pre-NAC RAD51 status. Moreover, RAD51 status can be evaluated in a significant proportion of treatment-naïve HGSC samples. As RAD51 status dynamically changes, sequential follow-up of RAD51 status might reflect the biological behavior of HGSCs.

Application of precision medicine based on next-generation sequencing and immunohistochemistry in ovarian cancer: a real-world experience

To evaluate the landscape of gene alterations and immunohistochemistry (IHC) profiles of patients with ovarian cancer for targeted therapy and investigate the real-world experience of applying precision medicine. Patients diagnosed with ovarian cancer between January 2015 and May 2021 at Severance Hospital and who underwent tumor next-generation sequencing (NGS) were reviewed. Data on germline mutation, IHC markers for mismatch repair deficiency (MMRd), programmed death ligand 1 (PD-L1) expression, and human epidermal growth factor receptor 2 (HER2) expression were acquired. The use of matched therapy and its clinical outcomes were evaluated. Of the 512 patients who underwent tumor NGS, 403 underwent panel-based germline testing. In patients who underwent both tests, tumor NGS identified 39 patients (9.7%) with A comprehensive review of germline mutation, IHC, and tumor NGS helped identify candidates for precision therapy in patients with ovarian cancer, a proportion of whom received matched therapy.

Investigation of PARP Inhibitor Resistance Based on Serially Collected Circulating Tumor DNA in Patients With BRCA -Mutated Ovarian Cancer

Abstract Purpose: Patient-specific molecular alterations leading to PARP inhibitor (PARPi) resistance are relatively unexplored. In this study, we analyzed serially collected circulating tumor DNA (ctDNA) from patients with BRCA1/2 mutations who received PARPis to investigate the resistance mechanisms and their significance in postprogression treatment response and survival. Experimental Design: Patients were prospectively enrolled between January 2018 and December 2021 (NCT05458973). Whole-blood samples were obtained before PARPi administration and serially every 3 months until progression. ctDNA was extracted from the samples and sequenced with a 531-gene panel; gene sets for each resistance mechanism were curated. Results: Fifty-four patients were included in this analysis. Mutation profiles of genes in pre-PARPi samples indicating a high tumor mutational burden and alterations in genes associated with replication fork stabilization and drug efflux were associated with poor progression-free survival on PARPis. BRCA hypomorphism and reversion were found in 1 and 3 patients, respectively. Among 29 patients with matched samples, mutational heterogeneity increased postprogression on PARPis, showing at least one postspecific mutation in 89.7% of the patients. These mutations indicate non-exclusive acquired resistance mechanisms—homologous recombination repair restoration (28%), replication fork stability (34%), upregulated survival pathway (41%), target loss (10%), and drug efflux (3%). We observed poor progression-free survival with subsequent chemotherapy in patients with homologous recombination repair restoration (P = 0.003) and those with the simultaneous involvement of two or more resistance mechanisms (P = 0.040). Conclusions: Analysis of serial ctDNAs highlighted multiple acquired resistance mechanisms, providing valuable insights for improving postprogression treatment and survival.

Comparison between weekly versus 3-weekly paclitaxel in combination with carboplatin as neoadjuvant chemotherapy in advanced ovarian cancer

To compare the efficacy and toxicity of dose-dense weekly paclitaxel and 3-weekly carboplatin (ddPC) as neoadjuvant chemotherapy (NAC) with the standard 3-weekly regimen. A retrospective study of patients diagnosed with stage IIIc and IV ovarian cancer who received at least one cycle of NAC followed by interval debulking surgery between August 2015 and January 2018 was conducted. Patient characteristics, clinical and pathological response to NAC, surgical and survival outcome, and adverse event were compared. A total of 23 patients in the ddPC group and 50 patients in the standard group received a median of 3 cycles of NAC. Rate of grade ≥3 neutropenia was significantly higher in the ddPC group than the standard (82.6% vs. 22.0%, p<0.001). Patients in the ddPC group underwent dose-reduction more frequently (34.8% vs. 4.00%, p=0.001). Normalization of cancer antigen-125 post-NAC occurred more frequently in the ddPC group (73.9% vs. 46.0%, p=0.030). No residual disease rate (43.5% vs. 60.0%, p=0.188) and chemotherapy response score of 3 (34.8% vs. 26.0%, p=0.441) were not statistically different between two groups. There was no statistical difference in progression free survival (PFS) at 2 years (36.3% vs. 28.4%, p=0.454). Cox proportional hazard model showed that ddPC was not a significant determinant of PFS (p=0.816). There was no difference between both regimens in terms of NAC response and survival outcomes. However, ddPC group showed higher hematologic toxicity requiring dose reduction.

Circulating Tumor DNA and BRCA Reversion Mutation in Advanced or Recurrent Ovarian Cancer Patients With Germline Mutation.

Increasing number of ovarian cancer patients are receiving PARP inhibitor as maintenance or salvage therapy. Predictive factors to PARP inhibitor other than BRCA mutation or HRD status as well as specific resistance mechanism are unknown. Thus, the objective of this study was to prospectively collect serial blood samples in ovarian cancer patients with germline BRCA mutation who receive PARP inhibitor. We investigated circulating tumor DNA (ctDNA) before patients are started on PARP inhibitor and every 3 months thereafter until progression on PARP inhibitor. Through assessment of the changes in ctDNA mutational landscape, we aimed to investigate resistance mechanism to PARP inhibitor including BRCA reversion mutation.