Advanced low grade serous ovarian cancer: A retrospective analysis of surgical and chemotherapeutic management in two high volume oncological centers

Controversies in the management of serous borderline tumors and low-grade serous ovarian cancer

Low-grade serous ovarian cancer has been recognized as a distinct oncologic entity for the last 20 years. Over the last 10 years, treatment strategies tailored to the biological and clinical characteristics of the disease have been tested and implemented. However, several key controversies remain. Here, we articulate the uncertainties surrounding the identification of the tissues of origin of low-grade serous ovarian cancer and its precursor lesion, the serous borderline tumor, the challenges in identifying molecular drivers of low-grade serous ovarian cancer, where a driver mutation in the mitogen-activated protein kinase pathway has not been identified, and discuss the phenomenon of co-existent low- and high-grade components in a tumor. In the clinical arena, we discuss the challenges surrounding fertility preservation in young patients, difficulties encountered in patients with unresectable disease, and the controversy surrounding the recommendation of adjuvant chemotherapy. We also discuss the role of secondary debulking surgery, how to order the administration of biological therapies, and the key issues in accelerating the discovery and development of new therapies. For many of these issues, the solution lies in improved international collaboration and cooperation. For each, we allude to how this might best be achieved.

Primary versus interval cytoreductive surgery in patients with rare epithelial or non-epithelial ovarian cancer

BACKGROUND

The standard treatment for advanced epithelial ovarian cancer is primary cytoreductive surgery, with the goal of achieving no residual disease. Neoadjuvant chemotherapy and interval cytoreductive surgery can be viable treatment options for patients with extensive disease that precludes complete tumor removal during initial surgery, or when significant comorbidities increase the surgical risk without adversely impacting overall survival rates. However, published studies mostly included patients with high-grade serous ovarian cancer, with an underrepresentation of non-high-grade serous epithelial and non-epithelial cancers. This review aimed to provide an overview of the available data on the outcomes of primary cytoreductive surgery versus interval cytoreduction in patients with rare ovarian cancer histotypes.

METHODS

Published literature on primary versus interval cytoreductive surgery in non-high-grade serous ovarian cancers from 2004 to 2024 was searched using PubMed, EMBASE, and Google Scholar and reported for each histological subtype. The outcomes of patients with low-grade serous, endometrioid, clear-cell, and mucinous carcinomas after neoadjuvant chemotherapy were reviewed. Furthermore, the results following neoadjuvant chemotherapy in non-epithelial ovarian cancers, such as ovarian germ cell tumors, sex cord-stromal tumors, and small-cell carcinoma of the ovary, have also been reported. Most data were derived from retrospective studies, with heterogeneity in design.

RESULTS & CONCLUSIONS

Several ovarian cancer histotypes, including low-grade serous and mucinous carcinomas, may be less responsive than high-grade serous carcinomas to neoadjuvant chemotherapy. Consequently, primary cytoreduction with maximal surgical effort may confer a survival advantage. Other tumors responded well to neoadjuvant chemotherapy, allowing for interval fertility-sparing surgeries. Additional evidence is required because no prospective studies are currently available. Given the low incidence of these diseases, randomized controlled trials may not be feasible. However, national or international registries could play a pivotal role in determining the optimal approach for managing patients with these rare histotypes.

Novel Targeted Agents in Advanced and Recurrent Low-Grade Serous Ovarian Cancer: A Silver Lining in the Therapy of a Chemoresistant Disease?

Low-grade serous ovarian carcinoma (LGSOC) is a rare subtype of epithelial ovarian cancer, characterized by a unique molecular background and specific clinical behavior. A growing body of molecular data underscores LGSOC as a distinct disease entity; however, clinical evidence on the optimal treatment regimens for LGSOC remains limited due to the low incidence of the disease. Consequently, treatment recommendations for LGSOC are still often derived from findings on the more common high-grade serous ovarian carcinoma (HGSOC) and typically focus on radical cytoreductive surgery and platinum-based chemotherapy. Since LGSOCs typically exhibit only limited responsiveness to platinum-based chemotherapy, the clinical management of advanced and recurrent LGSOCs remains a significant therapeutic challenge and often results in limited treatment options and suboptimal outcomes. Recent advances in molecular profiling and the identification of new, promising targets, such as the mitogen-activated protein kinase (MAPK) pathway, offer hope for improving both the prognosis and health-related quality of life in affected patients. Given the high unmet clinical need to establish new therapeutic standards beyond cytotoxic chemotherapy, this review aims to summarize the most promising molecular targets and emerging targeted agents.

Outcome and prognostic factors of low‑grade serous ovarian cancer: An observational retrospective study

Low-grade serous ovarian cancer (LGSOC) is a very rare histological subtype of serous ovarian cancer, representing ~2% of all epithelial ovarian cancer cases. LGSOC has a better prognosis but a lower response rate to chemotherapy in comparison to high-grade serous ovarian carcinoma (HGSOC). The present study is a retrospective review of the medical records of all patients with histologically proven LGSOC diagnosed and treated in a single institute between January 2003 and December 2019. A total of 23 patients diagnosed with LGSOC and treated at King Faisal Specialist Hospital and Research Center (Riyadh, Saudi Arabia) were identified. The median age at diagnosis was 45.5 years (range, 26-66 years) and the median body mass index was 26.1 (range, 18-43). A total of 21 patients (91.3%) had de novo LGSOC, whereas only 2 patients (8.7%) had LGSOC that had transformed from serous borderline ovarian tumors and recurred. A total of 8 patients (34.8%) were diagnosed with International Federation of Gynecology and Obstetrics stage IV, whereas 3 (13.0%), 3 (13.0%) and 9 (39.1%) were diagnosed with stages I, II and III, respectively. In addition, 10 (43.5%), 5 (21.7%), and 3 (13.0%) patients had complete response, stable disease and partial response statuses after first-line therapy, respectively. At a median follow-up time of 34 months [95% confidence interval (CI), 25.32-42.69], the median progression-free survival (PFS) time was 75.2 months (95% CI, 17.35-133.05) and the median overall survival (OS) time was not reached. In conclusion, LGSOC exhibited better PFS and OS times than HGSOC as compared with data from the literature, and there is the option for systemic treatment (chemotherapy or hormonal therapy). Optimal cytoreduction showed numerically higher, but non-significant, PFS and OS times compared with suboptimal debulking; however, the optimal systemic chemotherapy or hormonal treatment remains controversial.

Exploring novel approaches in the systemic therapy of low-grade serous carcinoma of the ovary: a literature review

By presenting a comprehensive analysis of low-grade serous carcinomas (LGSCs), a subset of epithelial ovarian cancers, this review delves into their distinct molecular characteristics, clinicopathological features and systemic therapy options, emphasizing their differences from high-grade serous carcinomas (HGSCs). Notably, LGSCs exhibit prevalent RAS/RAF/MEK/MAPK pathway activation, KRAS and BRAF mutations, and infrequent p53 mutations. While chemotherapy is commonly employed, LGSCs display lower responsiveness compared to HGSCs. Hormone therapy, particularly endocrine maintenance therapy, is explored due to the higher estrogen receptor expression. Novel therapeutic approaches involving CDK4/6 inhibitors, MEK inhibitors, and antiangiogenic agents like bevacizumab are also investigated. Ongoing clinical trials are striving to enhance LGSC treatment strategies, offering valuable insights for future therapeutic advancements in this challenging ovarian cancer subtype.

Oncogenic Pathways and Targeted Therapies in Ovarian Cancer

Epithelial ovarian cancer (EOC) is one of the most aggressive forms of gynaecological malignancies. Survival rates for women diagnosed with OC remain poor as most patients are diagnosed with advanced disease. Debulking surgery and platinum-based therapies are the current mainstay for OC treatment. However, and despite achieving initial remission, a significant portion of patients will relapse because of innate and acquired resistance, at which point the disease is considered incurable. In view of this, novel detection strategies and therapeutic approaches are needed to improve outcomes and survival of OC patients. In this review, we summarize our current knowledge of the genetic landscape and molecular pathways underpinning OC and its many subtypes. By examining therapeutic strategies explored in preclinical and clinical settings, we highlight the importance of decoding how single and convergent genetic alterations co-exist and drive OC progression and resistance to current treatments. We also propose that core signalling pathways such as the PI3K and MAPK pathways play critical roles in the origin of diverse OC subtypes and can become new targets in combination with known DNA damage repair pathways for the development of tailored and more effective anti-cancer treatments.

Case report: ex vivo tumor organoid drug testing identifies therapeutic options for stage IV ovarian carcinoma

Patients presenting with stage 4 ovarian carcinoma, including low-grade serous disease, have a poor prognosis. Although platinum-based therapies can offer some response, these therapies are associated with many side effects, and treatment resistance often develops. Toxic side effects along with disease progression render patients unable to receive additional lines of treatment and limit their options to hospice or palliative care. In this case report, we describe a patient with an unusual case of metastatic low-grade serous ovarian cancer with some features of high-grade disease who had received four previous lines of treatment and was suffering from atelectasis, pulmonary embolism, and hydronephrosis. A CLIA-certified drug sensitivity assay of an organoid culture derived from the patient's tumor (PARIS® test) identified several therapeutic options, including the combination of fulvestrant with everolimus. On this treatment regimen, the patient experienced 7 months of stable disease and survived nearly 11 months before succumbing to her disease. This case emphasizes the clinical utility of ex vivo drug testing as a new functional precision medicine approach to identify, in real-time, personalized treatment options for patients, especially those who are not benefiting from standard of care treatments.

Impact of adjuvant chemotherapy on the overall survival of patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery

OBJECTIVE

To investigate the use and outcomes of adjuvant chemotherapy for patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery.

METHODS

Patients diagnosed between 2010 and 2015 with International Federation of Gynecology and Obstetrics stage II-IV low-grade serous ovarian carcinoma who underwent primary debulking surgery with known residual disease status and had at least 1 month of follow-up were identified in the National Cancer Database. Adjuvant chemotherapy was defined as receipt of chemotherapy within 6 months of surgery. Overall survival was evaluated using the Kaplan-Meier method and compared with the log-rank test. A Cox model was constructed to control for a priori-selected confounders. A systematic review of the literature was also performed.

RESULTS

In total, 618 patients with stage II-IV low-grade serous ovarian carcinoma who underwent primary cytoreductive surgery were identified; 501 (81.1%) patients received adjuvant chemotherapy, while 117 (18.9%) patients did not. The median follow-up of the present cohort was 47.97 months. There was no difference in overall survival between patients who did and did not receive adjuvant chemotherapy (p=0.78; 4-year overall survival rates were 77.5% and 76.1%, respectively). After controlling for patient age, medical co-morbidities, disease stage, and residual disease status, administration of adjuvant chemotherapy was not associated with better overall survival (HR=0.87, 95% CI 0.55 to 1.38). Based on data from three retrospective studies, omission of adjuvant chemotherapy following cytoreductive surgery was not associated with worse progression-free survival benefit (HR=1.25, 95% CI 0.80 to 1.95) for patients with stage III-V low-grade serous ovarian carcinoma.

CONCLUSIONS

Adjuvant chemotherapy may not be associated with an overall survival benefit for patients with advanced-stage low-grade serous ovarian carcinoma following primary cytoreductive surgery.

Low-grade serous ovarian cancer: expert consensus report on the state of the science

Compared with high-grade serous carcinoma, low-grade serous carcinoma of the ovary or peritoneum is a less frequent epithelial ovarian cancer type that is poorly sensitive to chemotherapy and affects younger women, many of whom endure years of ineffective treatments and poor quality of life. The pathogenesis of this disease and its management remain incompletely understood. However, recent advances in the molecular characterization of the disease and identification of novel targeted therapies with activity in low-grade serous carcinoma offer the promise of improved outcomes. To update clinicians regarding recent scientific and clinical trial advancements and discuss unanswered questions related to low-grade serous carcinoma diagnosis and treatment, a panel of experts convened for a workshop in October 2022 to develop a consensus document addressing pathology, translational research, epidemiology and risk, clinical management, and ongoing research. In addition, the patient perspective was discussed. The recommendations developed by this expert panel-presented in this consensus document-will guide practitioners in all settings regarding the clinical management of women with low-grade serous carcinoma and discuss future opportunities to improve research and patient care.