Operability and chemotherapy responsiveness in advanced low-grade serous ovarian cancer. An analysis of the AGO Study Group metadatabase

Targeted Therapies in Low-Grade Serous Ovarian Cancers

OPINION STATEMENT

Low grade serous carcinoma of the ovary has been delineated as a separate entity from its counterpart high grade serous carcinoma of the ovary. Molecular profiling has helped to further characterize this disease process and has led to new and exciting treatment options. Surgery has always been a cornerstone of management both in primary and recurrent disease settings. Chemotherapy has been a long-standing backbone of adjuvant treatment, but its efficacy continues to be questioned. Hormonal therapy for upfront and recurrent disease is an effective treatment option with a high response rate and minimal side effects. Newer therapies including MEK, CDK 4/6, and PI3KCA inhibitors have emerged as exciting options for recurrent disease. Ongoing clinical trials will hopefully lead to additional therapeutic opportunities based on novel biomarkers in this disease.

High throughput screening identifies dasatinib as synergistic with trametinib in low grade serous ovarian carcinoma

BACKGROUND

Low grade serous ovarian carcinoma (LGSOC) is a distinct histotype of ovarian cancer characterised high levels of intrinsic chemoresistance, highlighting the urgent need for new treatments. High throughput screening in clinically-informative cell-based models represents an attractive strategy for identifying candidate treatment options for prioritisation in clinical studies.

METHODS

We performed a high throughput drug screen of 1610 agents across a panel of 6 LGSOC cell lines (3 RAS/RAF-mutant, 3 RAS/RAF-wildtype) to identify novel candidate therapeutic approaches. Validation comprised dose-response analysis across 9 LGSOC models and 5 high grade serous comparator lines.

RESULTS

16 hits of 1610 screened compounds were prioritised for validation based on >50% reduction in nuclei counts in over half of screened cell lines at 1000 nM concentration. 11 compounds passed validation, and the four agents of greatest interest (dasatinib, tyrosine kinase inhibitor; disulfiram, aldehyde dehydrogenase inhibitor; carfilzomib, proteasome inhibitor; romidepsin, histone deacetylase inhibitor) underwent synergy profiling with the recently approved MEK inhibitor trametinib. Disulfiram demonstrated excellent selectivity for LGSOC versus high grade serous ovarian carcinoma comparator lines (P = 0.003 for IC50 comparison), while the tyrosine kinase inhibitor dasatinib demonstrated favourable synergy with trametinib across multiple LGSOC models (maximum zero interaction potency synergy score 46.9). The novel, highly selective Src family kinase (SFK) inhibitor NXP900 demonstrated a similar trametinib synergy profile to dasatinib, suggesting that SFK inhibition is the likely driver of synergy.

CONCLUSION

Dasatinib and other SFK inhibitors represent novel candidate treatments for LGSOC and demonstrate synergy with trametinib. Disulfiram represents an additional treatment strategy worthy of investigation.

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.

The survival benefit associated with complete macroscopic resection in epithelial ovarian cancer is histotype specific

BACKGROUND

Complete macroscopic resection is a key factor associated with prolonged survival in ovarian cancer. However, most evidence derives from high-grade serous ovarian carcinoma, and the benefit of complete macroscopic resection in other histotypes is poorly characterized. We sought to determine which histotypes derive the greatest benefit from complete macroscopic resection to better inform future decisions on radical cytoreductive efforts.

METHODS

We performed multivariable analysis of disease-specific survival across 2 independent patient cohorts to determine the magnitude of benefit associated with complete macroscopic resection within each histotype.

RESULTS

Across both cohorts (Scottish: n = 1622; Surveillance, Epidemiology, and End Results [SEER]: n = 18 947), complete macroscopic resection was associated with prolonged disease-specific survival; this was more marked in the Scottish cohort (multivariable hazard ratio [HR] = 0.44, 95% confidence interval [CI] = 0.37 to 0.52 vs HR = 0.59, 95% CI = 0.57 to 0.62 in SEER). In both cohorts, clear cell ovarian carcinoma was among the histotypes to benefit most from complete macroscopic resection (multivariable HR = 0.23 and HR = 0.50 in Scottish and SEER cohorts, respectively); high-grade serous ovarian carcinoma patients demonstrated highly statistically significant and clinically meaningful survival benefit, but this was of lower magnitude than in clear cell ovarian carcinoma and endometrioid ovarian carcinoma across both cohorts. The benefit derived in low-grade serous ovarian carcinoma is also high (multivariable HR = 0.27 in Scottish cohort). Complete macroscopic resection was associated with prolonged survival in mucinous ovarian carcinoma patients in the SEER cohort (multivariable HR = 0.65), but the association failed to reach statistical significance in the Scottish cohort.

CONCLUSIONS

The overall ovarian cancer patient population demonstrates clinically significant survival benefit associated with complete macroscopic resection; however, the magnitude of benefit differs between histotypes.

Durable response to BRAF inhibitor monotherapy in recurrent metastatic low grade serous ovarian cancer

Low grade serous ovarian cancers (LGSOC) in an advanced setting have limited systemic treatment options. In this paper we report a case of metastatic LGSOC harboring a BRAF mutation, treated with dabrafenib. We discuss the clinical, pathologic and molecular characteristics as well as surgical considerations and ongoing investigations in LGSOC.

Innovations in Rare Gynecologic Cancer: Melanoma, Neuroendocrine, and Low-Grade Serous Ovarian

In the field of gynecologic cancer, low-grade serous ovarian cancer (LGSOC) has been poorly understood and underinvestigated until recently. Similarly, understanding of the distinct properties and therapeutic sensitivities of gynecologic melanoma and cervical neuroendocrine tumors has recently accelerated. For each of these rare cancers, we explore the epidemiology and natural history, discuss the prognosis, diagnostic testing, and contemporary molecular classification, and then deliberate existing and emerging therapeutic strategies. In LGSOC, we focus on the clinical relevance of recent molecular studies that shed light on the importance of mitogen-activated protein kinase (MAPK) pathway gene mutation and chromosome 1 copy-number change on prognosis and MEK inhibitor sensitivity. We also discuss the relative chemoresistance of this disease and the fact that attention is shifting to combinations of molecular therapies such as endocrine agents plus cyclin-dependent kinase 4/6 inhibitors or MEK inhibitors plus FAK inhibitors. Gynecologic tract melanomas harbor a lower frequency of canonical BRAF mutations, and have lower tumor mutational burden and immune cell infiltration than cutaneous melanomas (CMs). As a result, patients with this disease are less likely to respond to BRAF/MEK or immune checkpoint inhibition than patients with CM. Emerging strategies include the combination of antiangiogenic agents with immune checkpoint inhibitors and the use of adoptive cellular therapies. In cervical neuroendocrine cancer, we discuss the use of surgery in early-stage disease, and the uncertainties regarding the role of radiotherapy. We also explore the evidence for chemotherapy and emerging investigational strategies including the use of poly (ADP-ribose) polymerase inhibitors. For all situations, we explore the shared decision-making process with the patient.

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.

Novel Endocrine Therapeutic Opportunities for Estrogen Receptor-Positive Ovarian Cancer-What Can We Learn from Breast Cancer?

Low-grade serous ovarian cancer (LGSOC) is a rare ovarian malignancy primarily affecting younger women and is characterized by an indolent growth pattern. It exhibits indolent growth and high estrogen/progesterone receptor expression, suggesting potential responsiveness to endocrine therapy. However, treatment efficacy remains limited due to the development of endocrine resistance. The mechanisms of resistance, whether primary or acquired, are still largely unknown and present a significant hurdle in achieving favorable treatment outcomes with endocrine therapy in these patients. In estrogen receptor-positive breast cancer, mechanisms of endocrine resistance have been largely explored and novel treatment strategies to overcome resistance have emerged. Considering the shared estrogen receptor positivity in LGSOC and breast cancer, we wanted to explore whether there are any parallel mechanisms of resistance and whether we can extend endocrine breast cancer treatments to LGSOC. This review aims to highlight the underlying molecular mechanisms possibly driving endocrine resistance in ovarian cancer, while also exploring the available therapeutic opportunities to overcome this resistance. By unraveling the potential pathways involved and examining emerging strategies, this review explores valuable insights for advancing treatment options and improving patient outcomes in LGSOC, which has limited therapeutic options available.

Trps1 predicts poor prognosis in advanced high grade serous ovarian carcinoma

TRPS1 is aberrantly expressed in a variety of tumors, including breast, prostate, and gastric cancers, and is strongly associated with tumorigenesis or prognosis. However, the role of TRPS1 in high grade serous ovarian carcinoma (HGSC) is unknown. We investigated the relationship between TRPS1 expression and clinicopathology in HGSC patients. The tumor-related regulatory mechanisms of TRPS1 was explored through in vivo and vitro experiments. The results showed that TRPS1 was highly expressed in HGSC compared to normal tissues. It was also linked to the cell proliferation index Ki67 and poor prognosis. In vivo experiments showed that knockdown of TRPS1 could inhibit tumor growth. In vitro experiments, knockdown of TRPS1 inhibited the proliferation of ovarian cancer cells. TRPS1 exerted its regulatory role as a transcription factor, binding to the PSAT1 promoter and promoting the expression of PSAT1 gene. Meanwhile, PSAT1 was positively correlated with CCND1 expression. These results suggest that TRPS1 affects HGSC proliferation and cell cycle by regulating PSAT1 and thus CCND1 expression.

Advances in precision therapy of low-grade serous ovarian cancer: A review

Low-grade serous ovarian carcinoma (LGSOC) is a rare subtype of ovarian cancer that accounts for approximately 6% to 10% of serous ovarian cancers. The clinical treatment of LGSOC is similar to that of high-grade serous ovarian carcinoma, however, its clinical and molecular characteristics are different from those of high-grade serous ovarian carcinoma. This article reviews the research on gene diagnosis, surgical treatment, chemotherapy, and biological therapy of LGSOC, providing reference for clinical diagnosis and treatment of LGSOC. Surgery is the cornerstone of LGSOC treatment and maximum effort must be made to achieve R0 removal. Although LGSOC is not sensitive to chemotherapy, postoperative platinum-based combination chemotherapy remains the first-line treatment option for LGSOC. Additional clinical trials are needed to confirm the clinical benefits of chemotherapy and explore new chemotherapy protocols. Hormone and targeted therapies may also play important roles. Some patients, particularly those with residual lesions after treatment, may benefit from hormone maintenance therapy after chemotherapy. Targeted therapies, such as MEKi, show good application prospects and are expected to change the treatment pattern of LGSOC. Continuing to further study the genomics of LGSOC, identify its specific gene changes, and combine traditional treatment methods with precision targeted therapy based on second-generation sequencing may be the direction for LGSOC to overcome the treatment bottleneck. In future clinical work, comprehensive genetic testing should be carried out for LGSOC patients to accumulate data for future scientific research, in order to find more effective methods and drugs for the treatment of LGSOC.

Preclinical efficacy of RAF/MEK clamp avutometinib in combination with FAK inhibition in low grade serous ovarian cancer

OBJECTIVES

Low-grade-serous-ovarian-carcinoma (LGSOC) is characterized by a high recurrence rate and limited therapeutic options. About one-third of LGSOC contains mutations in MAPK pathway genes such as KRAS/NRAS/BRAF. Avutometinib is a dual RAF/MEK inhibitor while defactinib and VS-4718 are focal-adhesion-kinase-inhibitors (FAKi). We determined the preclinical efficacy of avutometinib±VS-4718 in LGSOC patient-derived-tumor-xenografts (PDX).

METHODS

Whole-exome-sequencing (WES) was used to evaluate the genetic fingerprint of 3 patient-derived LGSOC (OVA(K)250, PERIT(M)17 and A(PE)148). OVA(K)250 tissue was successfully xenografted as PDX into female CB17/lcrHsd-Prkdc/SCID-mice. Animals were treated with either control, avutometinib, VS-4718, or avutometinib/ VS-4718 once daily five days on and two days off through oral gavage. Mechanistic studies were performed ex vivo using avutometinib±defactinib treated LGSOC tumor samples by western blot.

RESULTS

WES results demonstrated wild-type KRAS in all 3 LGSOC. OVA(K)250 PDX showed gain-of-function mutations (GOF) in PTK2 and PTK2B genes, and loss-of-heterozygosity in ADRB2, potentially sensitizing to FAK and RAF/MEK inhibition. The combination of avutometinib/ VS-4718 demonstrated strong tumor-growth inhibition compared to controls starting at day 9 (p < 0.002) in OVA(K)250PDX. By 60 days, mice treated with avutometinib alone and avutometinib/VS-4718 were still alive; compared to median survival of 20 days in control-treated mice and of 35 days in VS-4718-treated mice (p < 0.0001). By western-blot assays exposure of OVA(K)250 to avutometinib, FAKi defactinib and their combination demonstrated decreased phosphorylated FAK (p-FAK) as well as decreased p-ERK.

CONCLUSION

Avutometinib, and to a larger extent its combination with FAK inhibitor VS-4718, demonstrated promising in vivo activity against a KRAS wild-type LGSOC-PDX. These data support the ongoing registration-directed study (RAMP201/NCT04625270).

A phase II, multicenter, open-label study of abemaciclib and letrozole in patients with estrogen receptor-positive rare ovarian cancer: ALEPRO trial

BACKGROUND

Low-grade serous and endometrioid ovarian cancers and adult-type granulosa cell tumors are rare ovarian malignancies that show high estrogen receptor positivity. Recurrences of these subtypes of ovarian cancer are often treated with conventional chemotherapy, although response rates are disappointing.

PRIMARY OBJECTIVE

To determine the overall response rate of the combination therapy of abemaciclib and letrozole in patients with estrogen receptor-positive rare ovarian cancers.

STUDY HYPOTHESIS

The combination therapy of abemaciclib and letrozole will provide a clinically meaningful therapeutic benefit, with an overall response rate of >25%.

TRIAL DESIGN

This is a phase II, international, multicenter, open-label, single-arm study to evaluate the efficacy and safety of abemaciclib and letrozole in patients with advanced, recurrent, and/or metastatic estrogen receptor-positive, rare ovarian cancer. The study will follow a tandem two-stage design.

MAJOR INCLUSION/EXCLUSION CRITERIA

Patients must have histologically confirmed low-grade serous/endometrioid ovarian cancer or adult-type granulosa cell tumor with estrogen receptor positivity on immunohistochemistry. Patients need to have recurrent and measurable disease according to Radiologic Evaluation Criteria in Solid Tumors (RECIST) version 1.1. A maximum of two prior lines of endocrine therapy are allowed, and patients cannot have previously received a cyclin-dependent kinase inhibitor. Patients with platinum-refractory disease are not allowed in any stage of the study.

PRIMARY ENDPOINT

Investigator-assessed confirmed overall response rate, defined as the proportion of patients with a complete or partial response according to RECIST v1.1.

SAMPLE SIZE

40 to 100 patients will be included, depending on the results of the interim analysis. Patients will be included in Belgium, France and the Netherlands.

ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS

Patient recruitment will be completed by the end of 2025 and reporting of the final study results will be done by the end of 2027.

TRIAL REGISTRATION NUMBER

NCT05872204.

ESGO-ESMO-ESP consensus conference recommendations on ovarian cancer: pathology and molecular biology and early, advanced and recurrent disease

The European Society of Gynaecological Oncology, the European Society for Medical Oncology (ESMO) and the European Society of Pathology held a consensus conference (CC) on ovarian cancer on 15-16 June 2022 in Valencia, Spain. The CC panel included 44 experts in the management of ovarian cancer and pathology, an ESMO scientific advisor and a methodologist. The aim was to discuss new or contentious topics and develop recommendations to improve and harmonise the management of patients with ovarian cancer. Eighteen questions were identified for discussion under four main topics: (i) pathology and molecular biology, (ii) early-stage disease and pelvic mass in pregnancy, (iii) advanced stage (including older/frail patients) and (iv) recurrent disease. The panel was divided into four working groups (WGs) to each address questions relating to one of the four topics outlined above, based on their expertise. Relevant scientific literature was reviewed in advance. Recommendations were developed by the WGs and then presented to the entire panel for further discussion and amendment before voting. This manuscript focuses on the recommendation statements that reached a consensus, their voting results and a summary of evidence supporting each recommendation.

Retrospective analysis of uterine involvement in low grade serous ovarian carcinoma

OBJECTIVES

Low grade serous ovarian carcinoma (LGSOC) accounts for 2.5% of all ovarian carcinoma more affects younger women than high grade serous ovarian carcinoma. Hysterectomy is performed routinely for LGSOC treatment, but fertility sparring surgery (FSS) is feasible for some early stages. Currently, there is no study about uterine involvement in LGSOC. We evaluate uterine involvement in LGSOC patients and aim to identify pre-operative predictive factors.

METHODS

Retrospective observational study of LGSOC patients treated between January 2000 and May 2022 in the Hospices Civils de Lyon. All cases were viewed, reviewed or approved by an expert pathologist.

RESULTS

Among 535 serous ovarian carcinomas, 26 were included. Most patients (73 %) had FIGO III disease. Median OS was 115 months and median PFS was 42 months. Uterine involvement was found in 58 % patients who underwent hysterectomy (14/24), serosal involvement was the most frequent type of involvement (n = 13, 54 %). Myometrial involvement was found in 8 patients (33 %) and was associated with serosal involvement (7/8). Among patients with a macroscopic disease-free uterus during exploratory laparoscopy, 31 % had a microscopic serosal involvement. None patient with presumed early stage (FIGO I) were upstaged due to uterine involvement (serosal or myometrial). In patients with stage FIGO IIII, 72 % of uterine involvement were found. Univariate analysis did not show any predictive factor of myometrial involvement. There was no difference on OS nor PFS between patients with or without myometrial involvement.

CONCLUSIONS

In early stages LGSOC, FSS may be considered for selected patients. In advanced stages, hysterectomy should be performed routinely, since no predictive factor for uterine involvement were identified.

Low-grade versus high-grade serous ovarian cancer: comparison of surgical outcomes after secondary cytoreductive surgery

OBJECTIVE

Retrospective series have shown secondary cytoreductive surgery improves oncological outcomes in recurrent low-grade serous ovarian cancer. We aim to compare surgical procedures and complications between patients with low-grade and high-grade recurrent serous ovarian cancer.

METHODS

This retrospective single-institution study includes patients with recurrent low-grade and high-grade serous ovarian cancer undergoing surgery between January 2012 to December 2021. Patients were propensity matched 1:3 for residual tumor at first surgery, presence of ascites and performance status. Complexity of surgery and postoperative complications were analyzed.

RESULTS

A total of 116 patients undergoing secondary cytoreductive surgery were included with 29 patients (25%) having low-grade ovarian cancer. The median age of the patients was 54 years (range: 19-85) and 57 years (range: 29-78) in low-grade and high-grade ovarian cancer, respectively (p=0.13). Stages III/IV at diagnosis were more frequent in patients with high-grade ovarian cancers (p<0.001). Peritoneal involvement was higher in low-grade compared with high-grade ovarian cancer as shown by the higher rate of diaphragmatic (41.4% vs 21.8%, p=0.05), abdominal wall (41.4% vs 18.4%, p=0.02) and pelvic (51.7% vs 21.8%, p=0.01) peritonectomy. Multiple bowel resections were higher in low-grade ovarian cancer (24.1% vs 8.0%, p=0.04), while high-grade ovarian cancer had a higher rate of nodal recurrences (73.2%% vs 37.9%, p=0.03). Overall, surgical complexity was higher in low-grade ovarian cancer (58.6% vs 36.8%; p=0.05), with higher median estimated blood loss (400 vs 200 mL; p=0.01) compared with high-grade. Complete cytoreduction was achieved in 26 patients (89.7%) with low-grade and 84 (96.6%) with high-grade (p=0.16) ovarian cancer, with no significant differences in postoperative complications.

CONCLUSIONS

Secondary cytoreductive surgery in low-grade serous ovarian cancer patients was associated with higher complexity, multiple bowel resections, and higher median estimated blood loss than in high-grade serous ovarian cancer. The comparable rate of postoperative complications suggests that secondary cytoreductive surgery in this group of patients is feasible in expert centers.

Maintenance therapy for newly and recurrent epithelial ovarian cancer: current therapies and future perspectives

PURPOSE OF REVIEW

Epithelial ovarian cancer (EOC) is the fifth cause of cancer death among women, and 70-80% of patients relapse within 2 years from the last cycle of first-line chemotherapy despite a complete response to chemotherapy and optimal debulking surgery. In this context, the goal of the maintenance treatment strategy is to prolong the time to recurrence. The recent development of targeted molecular therapies resulted in a broader spectrum of maintenance therapeutic options with consequent higher clinical benefit but less toxicity. This review summarizes the currently available maintenance strategies for newly and recurrent EOC, focusing on the decision-making process to personalize treatment and future perspectives.

RECENT FINDINGS

Over the past 10 years, several studies have demonstrated the clear benefit in terms of survival with the addition of a maintenance treatment strategy over the 'watchful waiting' approach both in the first line and recurrent setting. Since December 2016, the United States Food and Drug Administration and European Medicines Agency have approved four drugs for ovarian cancer maintenance based on the results of several clinical trials demonstrating efficacy and tolerability. These include the antiangiogenic drug Bevacizumab and three polyadenosine diphosphate-ribose polymerase (PARP) inhibitors: olaparib, niraparib, and rucaparib.

SUMMARY

These data led American and European Treatment guidelines to include bevacizumab, olaparib, niraparib, rucaparib, and combination bevacizumab-olaparib as maintenance treatment options in first-line and recurrent ovarian cancer therapy. However, with the availability of different maintenance options, identifying the best treatment choice for each patient can be challenging, and several clinical and molecular aspects have to be taken into account in the decision-making process.

Complete Response With Trametinib in Advanced Low-Grade Serous Ovarian Carcinoma: A Case Report

Low-grade serous ovarian carcinoma (LGSOC) is an uncommon subtype of ovarian cancer, and it is usually associated with reduced sensitivity to chemotherapy and worse outcomes. We present a case involving a 45-year-old female patient diagnosed with stage III-C low-grade serous ovarian carcinoma (LGSOC) in 2013. She achieved a complete response for 29 months after undergoing platinum-based chemotherapy and interval cytoreduction. However, in 2016, both local and distant relapses were observed. As there was no benefit from hormonal therapy and the patient refused chemotherapy, bevacizumab was initiated, resulting in disease stabilization for 30 months. At disease progression, trametinib was proposed, and the patient experienced an ongoing sustained complete response for over 36 months. To the best of our knowledge, this is the first report, outside of a clinical trial, regarding a complete response with single agent MEK inhibitor therapy in a patient with recurrent LGSOC, with unknown BRAF V600E mutation. We present the following case in accordance with the CAse REports (CARE) checklist.

Treatment of Recurrent Low-grade Serous Ovarian Cancer With MEK Inhibitors: A Systematic Review

OBJECTIVE

Low-grade serous ovarian cancer (LGSC) represents 5% of all epithelial ovarian cancers. They are characterized by indolent growth and KRAS and BRAF mutations, differing from high-grade serous ovarian cancer both clinically and molecularly. LGSC has low response rates to traditional systemic therapies, including chemotherapy and hormonal therapy. The objective of this systematic review was to appraise the literature describing the efficacy of MEK inhibitors in the treatment of LGSC.

METHODS

A comprehensive search was conducted of the following databases: Medline ALL, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Sciences, ClinicalTrials.gov, International Clinical Trials Registry Platform (ICFRP), and International Standard Randomized Controlled Trials Number (ISRCTN) Registry. All studies investigating MEKi in the treatment of LGSC in the adjuvant or recurrent setting for patients 18 years of age or older were included. All titles/abstracts were then screened by 2 independent reviewers (A.K. and C.C.). The full-text articles were then screened. All disagreements were resolved by a third independent reviewer (T.Z.). Two independent reviewers (A.K. and C.C.) extracted data from the studies deemed eligible for final review.

RESULTS

A total of 2108 studies were identified in the initial search. Of these, a total of 4 studies met the eligibility criteria for systematic review. In these studies, 416 patients were treated with an MEKi alone. All patients included in the studies were being treated for LGSC in the recurrent setting. Varied results and efficacy of the MEKi were reported in each study.

CONCLUSIONS

The results highlighted in this systematic review demonstrate varied responses to MEKi for recurrent LGSC. Further research is needed in this field comparing the efficacy to current therapies, as well as to further evaluate the safety and toxicity profile with long-term use of MEKi.

Circulating small extracellular vesicles microRNAs plus CA-125 for treatment stratification in advanced ovarian cancer

BACKGROUND

No residual disease (R0 resection) after debulking surgery is the most critical independent prognostic factor for advanced ovarian cancer (AOC). There is an unmet clinical need for selecting primary or interval debulking surgery in AOC patients using existing prediction models.

METHODS

RNA sequencing of circulating small extracellular vesicles (sEVs) was used to discover the differential expression microRNAs (DEMs) profile between any residual disease (R0, n = 17) and no residual disease (non-R0, n = 20) in AOC patients. We further analyzed plasma samples of AOC patients collected before surgery or neoadjuvant chemotherapy via TaqMan qRT-PCR. The combined risk model of residual disease was developed by logistic regression analysis based on the discovery-validation sets.

RESULTS

Using a comprehensive plasma small extracellular vesicles (sEVs) microRNAs (miRNAs) profile in AOC, we identified and optimized a risk prediction model consisting of plasma sEVs-derived 4-miRNA and CA-125 with better performance in predicting R0 resection. Based on 360 clinical human samples, this model was constructed using least absolute shrinkage and selection operator (LASSO) and logistic regression analysis, and it has favorable calibration and discrimination ability (AUC:0.903; sensitivity:0.897; specificity:0.910; PPV:0.926; NPV:0.871). The quantitative evaluation of Net Reclassification Improvement (NRI) and Integrated Discrimination Improvement (IDI) suggested that the additional predictive power of the combined model was significantly improved contrasted with CA-125 or 4-miRNA alone (NRI = 0.471, IDI = 0.538, p < 0.001; NRI = 0.122, IDI = 0.185, p < 0.01).

CONCLUSION

Overall, we established a reliable, non-invasive, and objective detection method composed of circulating tumor-derived sEVs 4-miRNA plus CA-125 to preoperatively anticipate the high-risk AOC patients of residual disease to optimize clinical therapy.

Characterization and prognostic impact of ACTBL2-positive tumor-infiltrating leukocytes in epithelial ovarian cancer

Actin beta-like 2 (ACTBL2) was recently identified as a new mediator of migration in ovarian cancer cells. Yet, its impact on tumor-infiltrating and thus migrating leukocytes (TILs) remains to date unknown. This study characterizes the subset of ACTBL2-expressing TILs in epithelial ovarian cancer (EOC) and elucidates their prognostic influence on the overall survival of EOC patients with special regard to different histological subtypes. Comprehensive immunohistochemical analyses of Tissue-Microarrays of 156 ovarian cancer patients revealed, that a tumor infiltration by ACTBL2-positive leukocytes was significantly associated with an improved overall survival (OS) (61.2 vs. 34.4 months; p = 0.006) and was identified as an independent prognostic factor (HR = 0.556; p = 0.038). This significant survival benefit was particularly evident in patients with low-grade serous carcinoma (OS: median not reached vs. 15.6 months, p < 0.001; HR = 0.058, p = 0.018). In the present cohort, ACTBL2-positive TILs were mainly composed of CD44-positive cytotoxic T-cells (CD8+) and macrophages (CD68+), as depicted by double-immunofluorescence and various immunohistochemical serial staining. Our results provide significant evidence of the prognostic impact and cellular composition of ACTBL2-expressing TILs in EOC. Complementary studies are required to analyze the underlying molecular mechanisms of ACTBL2 as a marker for activated migrating leukocytes and to further characterize its immunological impact on ovarian carcinogenesis.

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.

Clinical Observations and Outcomes in Advanced Low-Grade Serous Carcinoma of the Ovary: Case Series from a Tertiary Cancer Center

Low-grade serous carcinoma (LGSC) is a rare histologic subtype of ovarian cancer. We present detailed management of 15 cases of advanced LGSC from a tertiary cancer center of India. Fifteen cases of advanced LGSC who underwent cytoreductive surgery (CRS) were analyzed from a prospectively maintained database. Baseline demographic characteristics, surgical details, and chemotherapy details were recorded. Descriptive statistics were summarized, and progression-free survival (PFS) and overall survival (OS) were estimated. The median age was 37 years. Nine patients had received NACT. All cases were FIGO stage III. Mean PCI was 15. Eleven patients had a completeness of cytoreduction score of 0-1. The median surgical time was 7.5 h; nine patients required multiple gastrointestinal resections. Median blood loss was 2500 ml. Median postoperative ventilation, ICU stay, and hospital stays were 1, 2, and 16 days, respectively. One patient had a grade III complication. Four patients received adjuvant chemotherapy. There was no postoperative mortality at the end of 90 days of surgery. All the patients except one were offered hormonal maintenance therapy. At a median follow-up of 43 months, 4 patients were disease-free, 9 had a recurrence, one died of disease progression, and one was lost to follow-up. Most recurrences were locoregional in the peritoneal cavity or pelvis. Four-year OS and PFS were 71.8% and 29.7%, respectively. Advanced LGSCs occur mostly in young premenopausal women with favorable oncologic outcomes. Optimal CRS is the mainstay of treatment. Relative chemo-resistance and hormone receptor positivity provide an excellent therapeutic opportunity for endocrine therapy.

Molecular Results and Potential Biomarkers Identified from the Phase 3 MILO/ENGOT-ov11 Study of Binimetinib versus Physician Choice of Chemotherapy in Recurrent Low-Grade Serous Ovarian Cancer

PURPOSE

We present the results of a post hoc tumor tissue analysis from the phase 3 MILO/ENGOT-ov11 study (NCT01849874).

PATIENTS AND METHODS

Mutation/copy-number analysis was performed on tissue obtained pre-randomization. The Kaplan-Meier method was used to estimate progression-free survival (PFS). Unbiased univariate analysis, Cox regression, and binary logistic regression were used to test associations between mutation status and outcomes, including PFS and binary response by local RECIST 1.1.

RESULTS

MILO/ENGOT-ov11 enrolled 341 patients, ranging in age from 22 to 79, from June, 2013 to April, 2016. Patients were randomized 2:1 to binimetinib or physician's choice of chemotherapy (PCC). The most commonly altered gene was KRAS (33%). In 135 patients treated with binimetinib with response rate (RR) data, other detected MAPK pathway alterations included: NRAS (n = 11, 8.1%), BRAF V600E (n = 8, 5.9%), RAF1 (n = 2, 1.5%), and NF1 (n = 7, 5.2%). In those with and without MAPK pathway alterations, the RRs with binimetinib were 41% and 13%, respectively. PFS was significantly longer in patients with, compared with those without, MAPK pathway alterations treated with binimetinib [HR, 0.5; 95% confidence interval (CI) 0.31-0.79]. There was a nonsignificant trend toward PFS improvement in PCC-treated patients with MAPK pathway alterations compared with those without (HR, 0.82; 95% CI, 0.43-1.59).

CONCLUSIONS

Although this hypothesis-generating analysis is limited by multiple testing, higher RRs and longer PFS were seen in patients with low-grade serous ovarian cancer (LGSOC) treated with binimetinib, and to a lesser extent in those treated with PCC, who harbored MAPK pathway alterations. Somatic tumor testing should be routinely considered in patients with LGSOC and used as a future stratification factor.

Tumor biology and impact on timing of surgery in advanced epithelial ovarian cancer

Recent advances in epithelial ovarian cancer research have led to a shift in treatment strategy from the traditional 'organ-centric' to a personalized tumor biology-based approach. Nevertheless, we are still far behind an individualized approach for cytoreductive surgery in advanced ovarian cancer; the gold standard of primary treatment in combination with systemic agents. The impact of tumor biology on treatment sequence is still understudied. It is obvious, that response to platinum-based therapy is crucial for the success of neoadjuvant chemotherapy. While high-grade serous and endometrioid tumors are commonly characterized by an excellent response, other subtypes are considered poor responders or even resistant to platinum. Undoubtedly, neoadjuvant chemotherapy may filter poor responders, but to date, we still do not have appropriate alternatives to platinum-based chemotherapy in the neoadjuvant and first-line setting and 'adjusting' systemic treatment in cases of poor response to neoadjuvant chemotherapy remains elusive. Primary cytoreduction is still considered the gold standard for fit patients with operable tumor dissemination patterns, especially for those ovarian cancer subtypes that show poor response to platinum. Of note, even in high-grade serous ovarian cancer, approximately 20% of tumors are platinum resistant and the benefit of neoadjuvant chemotherapy in this subgroup is limited. Interestingly, these tumors are associated with the mesenchymal molecular subtype, which in turn correlates with high risk for residual disease after cytoreductive surgery and is characterized by the worst survival outcome among high-grade ovarian cancers. This leads to the question, how to best tailor surgical radicality at the onset of patients' presentation to avoid associated morbidity and with a moderate benefit. Here, we give an overview of recent advances of interaction between tumor biology and surgery in ovarian cancer.

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.

Rare Epithelial Ovarian Cancers: Low Grade Serous and Mucinous Carcinomas

The ovarian epithelial cancer histotypes can be divided into common and rare types. Common types include high-grade serous ovarian carcinomas and the endometriosis-associated cancers, endometrioid and clear-cell carcinomas. The less common histotypes are mucinous and low-grade serous, each comprising less than 10% of all epithelial carcinomas. Although histologically and epidemiologically distinct from each other, these histotypes share some genetic and natural history features that distinguish them from the more common types. In this review, we will consider the similarities and differences of these rare histological types, and the clinical challenges they pose.

Comprehensive Review of Serous Tumors of Tubo-Ovarian Origin: Clinical Behavior, Pathological Correlation, Current Molecular Updates, and Imaging Manifestations

Ovarian cancer is the eighth most common women's cancer worldwide, with the highest mortality rate of any gynecologic malignancy. On a global scale, the World Health Organization (WHO) reports that ovarian cancer has approximately 225,000 new cases every year with approximately 145,000 deaths. According to the National Institute of Health, Surveillance Epidemiology and End Results program (SEER) database, 5-year survival for women with ovarian cancer in the United States is 49.1%. High-grade serous ovarian carcinoma typically presents at an advanced stage and accounts for the majority of these cancer deaths. Given their prevalence and the lack of a reliable method for screening, early and reliable diagnosis of serous cancers is of paramount importance. Early differentiation of borderline, low and high-grade lesions can assist in surgical planning and support challenging intraoperative diagnoses. The objective of this article is to provide a review of the pathogenesis, diagnosis, and treatment of serous ovarian tumors, with a specific focus on the imaging characteristics that help to preoperatively differentiate borderline, low-grade, and high-grade serous ovarian lesions.

The highs and lows of serous ovarian cancer

Low-grade serous ovarian cancer was initially described as a distinct type of rare epithelial ovarian cancer 20 years ago; however, only recently have physicians begun to leverage the understanding of the clinical behavior and molecular profile of this disease for treatment. The use of routine next-generation sequencing has allowed a deeper understanding of the molecular drivers of this disease and shown how molecular alterations in mitogen-activated protein kinase pathway genes such as KRAS and BRAF can affect overall prognosis and disease behavior. The use of targeted therapies, including MEK inhibitors, BRAF kinase inhibitors, and other investigational targeted therapies are changing the way this disease is viewed and treated. In addition, endocrine therapy can provide prolonged disease stability with generally mild toxicity, as well as promising response rates in recent studies examining combination therapy with CDK 4/6 inhibitors in the upfront and recurrent setting. Once seen merely as a chemo-resistant form of ovarian cancer, recent studies have worked to harness the unique features of low-grade serous ovarian cancer to provide individualized treatment options for patients with this disease.

Trends in the use of neoadjuvant chemotherapy for low-grade serous ovarian cancer in the United States

OBJECTIVE

To describe trends in neoadjuvant chemotherapy (NACT) use for low-grade serous ovarian carcinoma (LGSOC) and to quantify associations between NACT and extent of cytoreductive surgery.

METHODS

We identified women treated for stage III or IV serous ovarian cancer in a Commission on Cancer accredited program between January 2004-December 2020. Regression models were developed to evaluate trends in NACT use for LGSOC, to identify factors associated with receipt of NACT, and to quantify associations between NACT and bowel or urinary resection at the time of surgery. Demographic and clinical factors were used for confounder control.

RESULTS

We observed 3350 patients who received treatment for LGSOC during the study period. The proportion of patients who received NACT increased from 9.5% in 2004 to 25.9% in 2020, corresponding to an annual percent change of 7.2% (95% CI 5.6-8.9). Increasing age (rate ratio (RR) 1.15; 95% CI 1.07-1.24), and stage IV disease (RR 2.66; 95% CI 2.31-3.07) were associated with a higher likelihood of receiving NACT. For patients with high-grade disease, NACT was associated with a decrease in likelihood of bowel or urinary surgery (35.3% versus 23.9%; RR 0.68, 95% CI 0.65-0.71). For LGSOC, NACT was associated with a higher likelihood of these procedures (26.6% versus 32.2%; RR 1.24, 95% CI 1.08-1.42).

CONCLUSION

NACT use among patients with LGSOC has increased from 2004 to 2020. While NACT was associated with a lower rate of gastrointestinal and urinary surgery among patients with high-grade disease, patients with LGSOC receiving NACT were more likely to undergo these procedures.

Chemotherapy response in low-grade serous ovarian carcinoma at a comprehensive cancer center: Readdressing the roles of platinum and cytotoxic therapies

BACKGROUND

Data on platinum sensitivity of low-grade serous ovarian carcinoma (LGSOC) in the upfront setting is lacking, and there is limited and contradictory information on chemotherapy responses in recurrent disease.

METHODS

Patients with LGSOC seen at a comprehensive cancer center from January 1, 1998 to September 30, 2021 were identified from institutional databases. Response to neoadjuvant chemotherapy (NACT) or adjuvant platinum-based chemotherapy and to second- to fifth-line regimens was retrospectively characterized by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Wilcoxon rank-sum and two-tailed Fisher exact tests were employed.

RESULTS

Of 50 patients, 12 received platinum doublets for suboptimal residual disease and 11 as NACT. Of 12 patients with suboptimal residual disease, seven (58%) achieved objective responses (five partial responses [PRs] and two complete responses); of the 11 patients who underwent NACT, one (9%) achieved a PR (p = .027). The 15 remaining patients had stable disease on first-line platinum chemotherapy. Of 44 patients who recurred, 20 had RECIST-evaluable responses to second-line and 27 to third-line chemotherapy. Objective response rates to platinum-based chemotherapy were 22% (two of nine) in the second line and 10% (one of 10) in the third. In second and third lines, highest response rates were observed with nonplatinum chemotherapy with bevacizumab, at 100% (two of two) and 30% (three of 10), respectively.

CONCLUSIONS

Primary platinum-based chemotherapy has moderate activity in LGSOC and minimal activity in the recurrent setting, suggesting standard definitions of platinum sensitivity may not apply in LGSOC. In the second and third lines, nonplatinum chemotherapy/bevacizumab elicited the highest response rates.

The impact of adjuvant antihormonal therapy versus observation on recurrence of borderline ovarian tumors: A retrospective cohort study

Objectives

Adjuvant management of borderline ovarian tumors (BOT) after surgical diagnosis and staging is not standardized. While many patients undergo observation alone, some providers have introduced the use of adjuvant antihormonal therapy for BOT, extrapolating from studies suggesting improvement in progression-free survival in the low-grade serous ovarian carcinoma population. We hypothesized that adjuvant antihormonal therapy after surgical diagnosis of BOT would improve progression-free survival compared to surveillance alone.

Methods

This is a retrospective review of BOT at one academic institution over thirteen years comparing management with antihormonal therapy, including aromatase inhibitors, progestins, and selective estrogen receptor modulators, to surveillance alone. Patients with concurrent malignancy were excluded. Data were abstracted from electronic medical records. Groups were compared by bivariate statistics.

Results

We identified 193 patients with BOT. Of these, 17 (8.8%) were treated with adjuvant antihormonal therapy and 24 (12.4%) recurred. Patients treated with antihormonal therapy were more likely to be obese (64.7% vs 37.9%, p = 0.032), have advanced-stage disease (70.6% vs 11.4%, p < 0.001), serous histotype (94.1% vs 59.4%, p = 0.005) or microinvasion (29.4% vs 9.7%, p = 0.030), and less likely to have undergone fertility-sparing surgery (18.8% vs 51.7%, p = 0.012). Use of antihormonal therapy was not associated with a difference in recurrence or survival.

Conclusions

This study is the first retrospective cohort review of adjuvant antihormonal therapy in BOT. We found that adjuvant antihormonal therapy for BOT is not associated with recurrence. While this single institution retrospective cohort study may lack the power to confirm or refute benefit, further studies could evaluate whether a subpopulation exists in whom antihormonal therapy is worthwhile.

Whole exome sequencing of low grade serous ovarian carcinoma identifies genomic events associated with clinical outcome

OBJECTIVES

Low-grade serous ovarian carcinoma (LGSOC) is a distinct, rare, ovarian cancer type characterised by younger patient age and intrinsic chemoresistance. Understanding the molecular landscape is crucial for optimising targeted therapy.

METHODS

Genomic data from whole exome sequencing of tumour tissue was analysed in a LGSOC cohort with detailed clinical annotation.

RESULTS

63 cases were analysed and three subgroups identified based on single nucleotide variants: canonical MAPK mutant (cMAPKm: 52%, KRAS/BRAF/NRAS), MAPK-associated gene mutation (MAPK-assoc: 27%) and MAPK wild-type (MAPKwt: 21%). NOTCH pathway disruption occurred across all subgroups. Tumour mutational burden (TMB), mutational signatures and recurrent copy number (CN) changes varied across the cohort with co-occurrence of chromosome 1p loss and 1q gain (CN Chr1pq) a recurrent feature. Low TMB and CN Chr1pq were associated with inferior disease-specific survival (HR 6.43; p < 0.001 and HR 3.29, p = 0.011 respectively). Stepwise genomic classification in relation to outcome resulted in four groups (TMB low; CN Chr1pq; MAPKwt/MAPKassoc; cMAPKm). 5 year disease-specific survival was 46%, 55%, 79% and 100% respectively for these groups. The two most favourable genomic subgroups were enriched for the SBS10b mutational signature, particularly the cMAPKm subgroup.

CONCLUSIONS

LGSOC comprises multiple genomic subgroups with distinct clinical and molecular features. Chr1pq CN arm disruption and TMB represent promising methods to identify individuals with poorer prognosis. Further investigation of the molecular basis for these observations is required. MAPKwt cases represent around a fifth of patients. NOTCH inhibitors represent a candidate therapeutic strategy worthy of exploration across these cases.

Distinct histopathological features are associated with molecular subtypes and outcome in low grade serous ovarian carcinoma

Low grade serous ovarian carcinoma (LGSOC) demonstrates unique clinical and molecular features compared to other ovarian cancer types. The relationship between common histological features of LGSOC and molecular events, such as hormone receptor expression patterns and MAPK gene mutation status, remains poorly understood. Recent data suggest some of these molecular features may be biomarkers of response to recently introduced biologically-targeted therapies, namely endocrine therapy and MEK inhibitors. We utilize a cohort of 63 pathologically-confirmed LGSOC cases with whole exome sequencing and hormone receptor expression data to investigate these relationships. LGSOC cases demonstrated uniformly high oestrogen receptor (ER) expression, but variable progesterone receptor (PR) expression intensity. 60% and 37% of cases demonstrated micropapillary and macropapillary patterns of stromal invasion, respectively. 63% of cases demonstrated desmoplasia, which was significantly associated with advanced disease stage and visible residual disease after cytoreductive surgery. MAPK-mutant cases (KRAS, BRAF, NRAS) more frequently demonstrated macropapillary stromal invasion, while Chr1p loss was associated with desmoplasia and low PR expression. Presence of micropapillary stromal invasion and low PR expression were associated with significantly poorer survival after accounting for stage and residual disease status. Together, these data identify novel relationships between histopathological features and molecularly-defined subgroups in LGSOC.

[Treatments for rare ovarian tumors: What's new?]

Even if each rare ovarian tumor (ROT) has a low incidence, the sum of all these entities represents almost the half of all ovarian neoplasms. Thus, development of dedicated clinical trial emerged as a prerequisite to improve their managements. Owing to the spreading of dedicated institutional networks and (supra)national collaborations, the number of clinical trials has increased the past few years, with different types of trials; while some focused on specific molecular features, others assessed innovative molecules. Furthermore, relevant randomized clinical trials were designed as a mean to position new treatment options. Currently, innovative molecular-driven trials, based on master protocol trials are emerging and may shed light towards the improvement of personalized medicine regarding ROT.

Effect of bevacizumab in advanced low grade serous ovarian cancer: Data from the MITO 22 trial

OBJECTIVE

The aim of the present analysis was to explore the efficacy of Bevacizumab (Bev) on survival outcome in advanced low grade serous ovarian cancer (LGSOC) both in first line and in recurrent setting.

METHODS

In retrospective observational multicenter study, we described the outcome of LGSOC patients enrolled in the MITO 22 study and treated with chemotherapy (CT) with or without Bev. Patients receiving Bev in first-line or in recurrence were considered and compared with patients receiving CT alone (stage III and IV in first line; platinum based-CT in second line). Descriptive and survival analyses were performed for each group.

RESULTS

Out of 128 patients included in MITO 22, 46 LGSOC patients receiving Bev in first line setting or at the time of first recurrence were identified. In first line, 30 patients received Bev + CT and 65 CT alone and the median PFS were 47.86 months (95% CI: 31.48 - NR) and 22.63 months (95% CI 15-39.24) (p-value 0.0392), respectively. In the recurrent setting, 16 patients who received Bev + CT were compared to 33 women treated with platinum-based CT alone. Median PFS were 37.1 months (95% CI: 13.42-40.56) and 11.22 months (95% CI: 8.26-15.63) (p-value 0.013), respectively.

CONCLUSIONS

Our study suggests that Bev might be effective in LGSOC both at diagnosis and at the time of relapse. These data warrants further studies.

Prediction of Surgical Outcome in Advanced Ovarian Cancer by Imaging and Laparoscopy: A Narrative Review

Maximal-effort upfront or interval debulking surgery is the recommended approach for advanced-stage ovarian cancer. The role of diagnostic imaging is to provide a systematic and structured report on tumour dissemination with emphasis on key sites for resectability. Imaging methods, such as pelvic and abdominal ultrasound, contrast-enhanced computed tomography, whole-body diffusion-weighted magnetic resonance imaging and positron emission tomography, yield high diagnostic performance for diagnosing bulky disease, but they are less accurate for depicting small-volume carcinomatosis, which may lead to unnecessary explorative laparotomies. Diagnostic laparoscopy, on the other hand, may directly visualize intraperitoneal involvement but has limitations in detecting tumours beyond the gastrosplenic ligament, in the lesser sac, mesenteric root or in the retroperitoneum. Laparoscopy has its place in combination with imaging in cases where ima-ging results regarding resectability are unclear. Different imaging models predicting tumour resectability have been developed as an adjunctional objective tool. Incorporating results from tumour quantitative analyses (e.g., radiomics), preoperative biopsies and biomarkers into predictive models may allow for more precise selection of patients eligible for extensive surgery. This review will discuss the ability of imaging and laparoscopy to predict non-resectable disease in patients with advanced ovarian cancer.

Laparoscopic selection for surgery in epithelial ovarian cancer. A short review

The role of laparoscopy as a treatment selection method in ovarian cancer patients is receiving growing attention in surgical practice in both early and advanced-stage disease. When the disease is confined to the ovary, intraoperative laparoscopic assessment of the tumour features is needed to select the best surgical approach in order to prevent intraoperative spillage of cancer cells which would negatively impact patient prognosis. The role of laparoscopy as a disease distribution assessment tool in cases of advanced-stage disease is now accepted by current guidelines as an effective treatment strategy selection. Indeed, a published and validated laparoscopic scoring system, based on laparoscopic assessed intra-abdominal disease dissemination features have been demonstrated to be a reliable predictor of optimal cytoreduction achievement. This subsequently reduces the exploratory laparotomy rate in both primary and interval debulking surgery setting. Furthermore, in cases of recurrent disease, the use of laparoscopy to predict whether complete tumour resection can be achieved is accepted by available guidelines. In this setting, the combination of laparoscopy and imaging techniques to manage platinum sensitive recurrent ovarian cancer cases showed a high accuracy in appropriately selected patients for secondary cytoreductive surgery. In this article we describe the role of laparoscopy in the treatment selection-process in ovarian cancer patients.

Molecular characteristics and clinical behaviour of epithelial ovarian cancers

Ovarian carcinoma (OC) is an umbrella term for multiple distinct diseases (histotypes), each with their own developmental origins, clinical behaviour and molecular profile. Accordingly, OC management is progressing away from a one-size-fits all approach, toward more molecularly-driven, histotype-specific management strategies. Our knowledge of driver events in high grade serous OC, the most common histotype, has led to major advances in treatments, including PARP inhibitor use. However, these agents are not suitable for all patients, most notably for many of those with rare OC histotypes. Identification of additional targeted therapeutic strategies will require a detailed understanding of the molecular landscape in each OC histotype. Until recently, tumour profiling studies in rare histotypes were sparse; however, significant advances have been made over the last decade. In particular, reports of genomic characterisation in endometrioid, clear cell, mucinous and low grade serous OC have significantly expanded our understanding of mutational events in these tumour types. Nonetheless, substantial knowledge gaps remain. This review summarises our current understanding of each histotype, highlighting recent advances in these unique diseases and outlining immediate research priorities for accelerating progress toward improving patient outcomes.

Stage, treatment and survival of low-grade serous ovarian carcinoma in the Netherlands: A nationwide study

INTRODUCTION

Serous ovarian carcinomas constitute the largest group of epithelial ovarian cancer (60%-75%) and are further classified into high- and low-grade serous carcinoma. Low-grade serous carcinoma (LGSC) is a relatively rare subtype (approximately 5% of serous carcinomas) and epidemiologic studies of large cohorts are scarce. With the present study we aimed to report trends in stage, primary treatment and relative survival of LGSC of the ovary in a large cohort of patients in an effort to identify opportunities to improve clinical practice and outcome of this relatively rare disease.

MATERIAL AND METHODS

Patients diagnosed with LGSC between 2000 and 2019 were identified from the Netherlands Cancer Registry (n = 855). Trends in FIGO stages and primary treatment were analyzed with the Cochran-Armitage trend test, and differences in and trends of 5-year relative survival were analyzed using multivariable Poisson regression.

RESULTS

Over time, LGSC was increasingly diagnosed as stage III (39.9%-59.0%) and IV disease (5.7%-14.4%) and less often as stage I (34.6%-13.5%; p < 0.001). Primary debulking surgery was the most common strategy (76.2%), although interval debulking surgery was preferred more often over the years (10.6%-31.1%; p < 0.001). Following primary surgery, there was >1 cm residual disease in only 15/252 patients (6%), compared with 17/95 patients (17.9%) after interval surgery. Full cohort 5-year survival was 61% and survival after primary debulking surgery was superior to the outcome following interval debulking surgery (60% vs 34%). Survival following primary debulking surgery without macroscopic residual disease (73%) was better compared with ≤1 cm (47%) and >1 cm residual disease (22%). Survival following interval debulking surgery without macroscopic residual disease (51%) was significantly higher than after >1 cm residual disease (24%). Except FIGO stage II (85%-92%), survival did not change significantly over time.

CONCLUSIONS

Over the years, LGSC has been diagnosed as FIGO stage III and stage IV disease more often and interval debulking surgery has been increasingly preferred over primary debulking in these patients. Relative survival did not change over time (except for stage II) and worse survival outcomes after interval debulking surgery were observed. The results support the common recommendation to perform primary debulking surgery in patients eligible for primary surgery.

Update on new treatments for rare ovarian tumours

PURPOSE OF REVIEW

In spite of their rarity when considered individually, the sum of all rare ovarian tumours (ROT) represent almost half of all ovarian malignancies. As such, their appropriate inclusion within dedicated clinical trials is essential for enhanced management.

RECENT FINDINGS

Supported by institutional expert national (e.g. TMRG) and international (e.g. ESGO) networks and owing to national (e.g. ARCAGY-GINECO) and international (e.g. ENGOT) collaborations dedicated to clinical research, the last few years have shown increased number of clinical trials dedicated to ROT. These either were based on specific molecular features of ROT (e.g. expression of oestrogen receptors for low-grade serous ovarian carcinomas and anastrazole evaluation in the PARAGON trial) or on the evaluation of innovative therapies (e.g. pembrolizumab within the ROT cohort from the AcSé Pembrolizumab multicentric basket trial). Furthermore, recent years have also shown the advent of randomized clinical trials. For instance, the ALIENOR trial positioned weekly paclitaxel as a new option for relapsed sex cord-stromal tumours, while the GOG281/LOGS trial raised trametinib as a new standard-of-care option for recurrent low-grade serous carcinomas.

SUMMARY

The last few years have exhibited a paradigm shift towards the possibility to develop dedicated trials for ROT, owing to international collaborations supported by institutional networks. Current trials, molecular-driven and based on innovative designs, are highly promising, as they may bring ROT management towards more personalized medicine.

Neoadjuvant chemotherapy in advanced epithelial ovarian cancer by histology: A SEER based survival analysis

To evaluate the prognostic effect of neoadjuvant chemotherapy (NACT) in advanced epithelial ovarian cancer (EOC) patients with different histological subtype. Stage III/IV EOC patients diagnosed between 2010 and 2018 were identified from the surveillance, epidemiology, and end results database (SEER) database and stratified by histological subtype. Kaplan-Meier analysis was used for the assessment of overall survival (OS) cause-specific survival (CSS) before and after matching for baseline characteristics between NACT and primary debulking surgery (PDS) groups. Cox proportional risk model was conducted to identify independent prognostic factors. A total of 13,582 patients were included in the analysis. Of them, 9505 (74.50%) received PDS and 3253 (25.50%) received NACT. Overall, an inferior OS and CSS was observed among patients with high-grade serous carcinoma (HGSC) receiving NACT, while NACT served as a protective factor in clear cell carcinoma and carcinosarcoma in both original cohorts and adjusted cohorts. For other histo-subtypes, PDS showed survival benefit over NACT in certain cohorts of models. Prognostic effect of NACT in advanced EOC differed from pathological subtypes. Although it served as a risk factor for HGSC, patients with less common subtypes may benefit from NACT.

Diagnostic and Therapeutic Pathway of Advanced Ovarian Cancer with Peritoneal Metastases

Over two thirds of ovarian cancer patients present with advanced stage disease at the time of diagnosis. In this scenario, standard treatment includes a combination of cytoreductive surgery and carboplatinum-paclitaxel-based chemotherapy. Despite the survival advantage of patients treated with upfront cytoreductive surgery compared to women undergoing neo-adjuvant chemotherapy (NACT) and interval debulking surgery (IDS) due to high tumor load or poor performance status has been demonstrated by multiple studies, this topic is still a matter of debate. As a consequence, selecting the adequate treatment through an appropriate diagnostic pathway represents a crucial step. Aiming to assess the likelihood of leaving no residual disease at the end of surgery, the role of the CT scan as a predictor of cytoreductive outcomes has shown controversial results. Similarly, CA 125 level as an expression of tumor load demonstrated limited applicability. On the contrary, laparoscopic assessment of disease distribution through a validated scoring system was able to identify, with the highest specificity, patients undergoing suboptimal cytoreduction and therefore best suitable for NACT-IDS. Against this background, with this article, we aim to provide a comprehensive review of available evidence on the diagnostic and treatment pathways of advanced ovarian cancer.

Trametinib for patients with recurrent low-grade serous ovarian cancer: A cost-effectiveness analysis

OBJECTIVE

The GOG 281/LOGS trial found that trametinib prolonged progression-free survival (PFS) in patients with recurrent low-grade serous ovarian cancer (LGSOC), compared with standard of care (SOC). The current study aimed to evaluate the cost-effectiveness of trametinib versus standard of care for recurrent LGSOC from the US payer perspective.

METHODS

A Markov model was adopted to compare the cost and effectiveness of trametinib and standard of care group in patients with recurrent LGSOC. Life years (LYs), quality-adjusted LYs (QALYs), lifetime costs, and incremental cost-effectiveness ratios (ICERs) were calculated. One-way, and probabilistic sensitivity analyses were performed to explore the model robustness.

RESULT

Trametinib group provided an additional 0.58 QALYs (1.14 LYs) and an incremental cost of $248,214 compared with the SOC group. The incremental cost-effectiveness ratio was $424,097 per QALY. The results of one-way sensitivity analyses suggested that our model was sensitive to the hazard ratio of OS and PFS between trametinib and SOC group, utility of PFS and the cycle cost of trametinib. Probabilistic sensitivity analyses revealed that there was 6% probability of the trametinib group being cost-effective at a willingness-to-pay (WTP) threshold of $150,000 per QALY.

CONCLUSIONS

From the US payer perspective, trametinib is not cost-effective for patients with recurrent LGSOC at the assumed WTP threshold of $150,000 per QALY. Based on the value standpoint, price reduction of trametinib is expected to improve the cost-effectiveness of trametinib in patients with recurrent LGSOC.

Low grade serous ovarian cancer - A rare disease with increasing therapeutic options

High-grade serous ovarian cancers (HGSOCs) most commonly arise from the fimbrial end of the fallopian tube and harbor TP53 gene mutations. In contrast, low-grade serous ovarian cancers (LGSOCs) appear to have different pathological, epidemiological, and clinical features and should be seen as a distinct serous epithelial ovarian cancer subtype. Our current understanding of LGSOC is limited, and treatment has generally been derived from the more common HGSOCs due to a lack of separate trial data. LGSOCs are characterized by slow tumor growth and are assumed to develop from serous borderline ovarian tumors as precursors. These cancers are often estrogen-receptor positive and show an activated mitogen-activated protein kinase pathway together with KRAS and BRAF mutations and, rarely, TP53 mutations. These characteristics are now commonly used to guide therapeutical decision making and, consequently, a substantial part of treatment consists of maintenance with endocrine treatment, thus balancing disease stabilization and mild toxicity. Additionally, new trials are ongoing that examine the role of targeted therapies such as MEK inhibitors in combination with endocrine treatments. The purpose of this work is to summarize current knowledge and present ongoing trial efforts for LGSOCs.

Low-Grade Serous Ovarian Carcinoma: a Retrospective Study from a Tertiary Cancer Institute

The aim of this study was to evaluate the clinico-pathological behaviour and treatment patterns of low-grade serous carcinomas (LGSC) of ovary treated at a regional cancer centre. A retrospective analysis was done for the histopathology-proven cases of low-grade serous ovarian carcinoma, treated at a tertiary cancer institute between January, 2010, and September, 2019. There were 28 patients identified from the medical records with low-grade serous ovarian carcinoma. Median age of the patients was 43 years [22-79 years]. Average BMI was 22.3 ± 4.0 kg/m2 [range 15.2-31.2]. Twenty-one (75%) were parous and 7 (25%) were non-parous women. Median CA125 level was 188 IU/ml [range 6-14,187 IU/ml]. Ten (35.7%) patients had primary surgery elsewhere and 8 (80%) out of these patients had to undergo repeat staging. Fertility sparing surgery (FSS) was offered to 4 (14.3%) patients. Five (17.8%) patients had received neoadjuvant chemotherapy for advanced disease and poor performance status. Almost 82.2% (23) of the patients had no macroscopic residual disease at the primary surgery. According to International Federation of Obstetrics and Gynaecologists (FIGO) stage for ovarian carcinoma, there were 7 (25%), 6 (21.4%), 13 (46.4%), and 2 (7.1%) patients in the stages I, II, III, and IV respectively. Post-operative adjuvant chemotherapy was offered to 7 (25%), hormonal therapy (anastrozole/tamoxifen) to 7 (25%), and rest of 14 (50%) patients were under surveillance. Median follow-up time for the study group was 36 months. Overall survival (OS) and disease-free survival (DFS) at 2 years was 96.4% and 89.1%, respectively. Low-grade serous carcinomas of ovary differ biologically from high-grade serous ovarian carcinoma. Surgery is the cornerstone of the treatment. Further research is needed to understand the behaviour of these tumours for effective treatment strategies in future.