Low-grade serous ovarian carcinoma: A comprehensive literature review.

BACKGROUND: Low-grade serous ovarian carcinoma (LGSOC) is a unique entity with clinical and molecular characteristics distinct from high-grade serous ovarian carcinoma (HGSOC). To date the majority of research has focused on the more common HGSOC, with treatment recommendations often extrapolated to LGSOC. Women with LGSOC are typically diagnosed younger and have indolent and relatively chemoresistant disease. Recently there have been major research advances in LGSOC. AIMS: This systematic review describes the epidemiological, clinical and molecular characteristics of LGSOC, with advances in research and novel treatment options also discussed. MATERIALS AND METHODS: A 10-year comprehensive systematic review of peer-reviewed literature was conducted, with a total of 132 abstracts read, 89 articles reviewed and 49 included in this review. RESULTS: This review highlights the clinical and molecular features of LGSOC, current and traditional treatment options and areas of current research into targeted agents. CONCLUSIONS: Our growing knowledge about LGSOC as a distinct clinical and molecular entity from HGSOC has led to the investigation of more targeted and tailored therapies as their clinical course, optimal management and therapeutic targets differ. There is a need for ongoing collaborative research to provide better treatment options for these patients.

Trends in the overall survival rates in women with advanced ovarian cancer in a single tertiary centre in New Zealand.

BACKGROUND: Survival rates for women diagnosed with ovarian cancer are much poorer than other gynaecological cancers and greatly depend on stage at diagnosis. A recent publication showed that unlike some other developed countries, there has been no improvement in the five-year survival rate for those diagnosed with ovarian cancer in New Zealand. AIM: To compare the five-year survival rate of women diagnosed with advanced ovarian cancer in a single tertiary hospital during two 36-month time periods 10 years apart. MATERIALS AND METHODS: An observational retrospective review of patient clinical notes, including all women diagnosed with stage three or four ovarian cancer between 2000 and 2002 (Cohort 1) and 2010-2012 (Cohort 2). Eligible patients were identified through the Regional Gynaecology Oncology database. Clinical notes were reviewed to compare the five-year survival rate between these two time periods and look at changes in patterns of care over time. RESULTS: Eighty-three women were diagnosed in 2000-2002 and 125 women in 2010-2012. There was no difference in five-year survival between cohorts (21.7% vs 23.2%, P = 0.80). Mean age at diagnosis did not differ between cohorts (62.1 years vs 63.5 years, P = 0.43); however, there were more women with stage four cancer in Cohort 2 (14% vs 30%, P = 0.01). In Cohort 2, more women were treated with neoadjuvant chemotherapy (20% vs 34%, P = 0.04) or chemotherapy only (6% vs 18%, P = 0.01). CONCLUSION: Five-year overall survival in women diagnosed with advanced ovarian cancer in our centre has not changed over the last 10 years.

The role of hormonal therapy in patients with relapsed high-grade ovarian carcinoma: a retrospective series of tamoxifen and letrozole.

BACKGROUND: Hormonal therapy is used as a treatment option in high-grade ovarian carcinoma (HGOC), but the role and choice of treatment remains unclear. Agents used include tamoxifen and aromatase inhibitors. Our aim was to evaluate the efficacy of tamoxifen (T) and letrozole (L) in HGOC in clinical practice and investigate factors influencing clinical outcome. METHODS: A retrospective review of patients with relapsed HGOC treated with either tamoxifen or letrozole at the Royal Marsden Hospital between 2007 and 2012 was performed. The primary endpoint of the study was objective response rate (ORR). Secondary endpoints included CA125 response, clinical benefit rate (CBR) and duration of response. Platinum-sensitivity and ER-status were evaluated as predictors of treatment response. RESULTS: 97 patients were included (43 T, 54 L); median age 63 years (20-92); 91% high-grade serous; median number of lines of prior chemotherapy 3 (1-8); 60% platinum-resistant, 40% platinum-sensitive; 52% ER + ve, 1% ER-ve, 47% unknown. 14 patients (6 T, 8 L) achieved a partial response, with ORR (RECIST) of 14% (T) and 15% (L). The CBR for ≥3 months was 65% (22/43) for tamoxifen and 56% (22/54) for letrozole. There was no significant difference in ORR (p = 0.99) or CBR (p = 0.14) between tamoxifen and letrozole. 22 patients (23%) had a CA-125 response with hormonal therapy (10 T - 23% and 12 L - 22%). ORR did not differ by platinum sensitivity (p = 0.42); or ER-status (positive vs unknown, p = 0.12). Responders to letrozole had longer durations of response than responders to tamoxifen (26 vs 11.5 months, p = 0.03), but equivalent disease stability duration (9.6 vs 7.2 months respectively, p = 0.11). CONCLUSIONS: Within the constraints of a retrospective study, we identified that patients treated with letrozole had a significantly longer duration of response than those treated with tamoxifen. Treatment with either tamoxifen or letrozole is a rational treatment option for patients with ER + ve HGOC, with equivalent ORR, CBR and disease stability.

Poor performance status (PS) is an indication for an aggressive approach to neoadjuvant chemotherapy in patients with advanced epithelial ovarian cancer (EOC).

BACKGROUND: Some guidelines suggest that poor performance status (PS) is a contraindication to 1st line chemotherapy. Poor PS is a known adverse prognostic factor in advanced epithelial ovarian cancer (EOC). We show in this retrospective analysis that 1st line chemotherapy in this patient group is not only safe but is associated with good outcomes. PATIENTS AND METHODS: A retrospective review of 114 patients with stage III/IV EOC, who presented with a PS ≥3 at diagnosis and treated as inpatients with upfront platinum-based chemotherapy between 2000 and 2013, at the Royal Marsden Hospital, was conducted. The association between clinical parameters and the likelihood of completion of chemotherapy and overall survival (OS) was assessed. RESULTS: 66% of patients completed ≥6cycles of platinum-based chemotherapy. Prognostic factors for completion of chemotherapy were improvement of PS during hospital stay (p<0.001) and doublet-chemotherapy with carboplatin/paclitaxel compared to single-agent carboplatin (p=0.004). A negative trend for completion of treatment was seen for patients with low albumin (<25g/l) and low CA125 levels at baseline. The median OS for all patients was 13.1months (95% CI: 10.4-15.8) and 21.2months (95% CI: 16.5-25.8) for those who completed 6cycles of chemotherapy. CONCLUSION: Upfront platinum-based chemotherapy is feasible, beneficial and tolerable for the majority of patients with advanced EOC and poor PS. Guidelines suggesting that best supportive care is the preferred option for poor PS patients with solid tumours should be revised to exclude those with advanced EOC. An aggressive approach utilising neoadjuvant carboplatin plus paclitaxel should be regarded as standard of care.

Abiraterone in patients with recurrent epithelial ovarian cancer: principal results of the phase II Cancer of the Ovary Abiraterone (CORAL) trial (CRUK - A16037).

BACKGROUND: Recurrent epithelial ovarian cancer (EOC) remains difficult to treat, with an urgent need for more therapy options. Androgens bind to the androgen receptor (AR), commonly expressed in EOC. CYP17 inhibitor abiraterone irreversibly inhibits androgen biosynthesis. The Cancer of the Ovary Abiraterone (CORAL) trial was designed to evaluate the clinical activity of abiraterone in EOC. PATIENTS & METHODS: CORAL was a multi-centre, open-label, non-randomised, 2-stage phase II clinical trial. Eligible patients had progression within 12 months of last systemic therapy and no prior hormonal anti-cancer agents. Patients received abiraterone 1000 mg daily plus 5 mg prednisone until progression. The primary endpoint was objective response rate (ORR) according to combined Response Evaluation Criteria in Solid Tumours/Gynaecological Cancer Intergroup (RECIST/GCIG) criteria at 12 weeks. Secondary endpoints included clinical benefit rate (CBR) at 12 weeks. RESULTS: A total of 42 patients were recruited; median age 65 (range 34-85) years; 37 (88.1%) had high-grade serous tumours; 20 (48%) had at least three prior lines of therapy; 29/40 (72.5%) were AR+. In stage 1, 1/26 response was observed (in an AR+, low-grade serous EOC); response lasted 47 weeks. Overall, 12 week ORR was 1/42 (2%), CBR was 11/42 (26%) (8/29 (28%) in AR+ patients). Disease control was ⩾6 months for 4/29 (14%). One patient (AR+, low-grade serous) had a RECIST response at 82 weeks. Four (10%) had grade ⩾3 hypokalaemia; 11 (26%) had dose delays. CONCLUSIONS: CORAL represents the first trial of an AR targeted agent in ovarian cancer. While responses were rare, a subset of patients achieved sustained clinical benefit. Targeting AR in EOC including low-grade serous cancer warrants further investigation. TRIAL REGISTRATION: CORAL is registered on the ISRCTN registry: ISRCTN63407050; http://www.isrctn.com/ISRCTN63407050.

Olaparib for the treatment of epithelial ovarian cancer.

INTRODUCTION: Despite recent advances in the management of epithelial ovarian cancer, overall survival rates remain poor, and there is a pressing need to develop novel therapeutic agents and maintenance strategies to improve outcomes for women with this disease. Olaparib, a potent oral poly(ADP-ribose) polymerase (PARP) inhibitor, has demonstrated antitumor activity in women with ovarian cancer, associated with homologous recombination deficiency. AREAS COVERED: This review outlines the rationale for PARP inhibitor therapy in ovarian cancer and summarizes the efficacy and tolerability data for olaparib to date. Ongoing phase III clinical trials of olaparib in ovarian cancer will be discussed. EXPERT OPINION: There are a number of issues regarding the optimal use of olaparib in ovarian cancer, including the identification of a homologous recombination deficiency signature to predict treatment response, establishment of the optimal treatment setting (maintenance or relapsed disease), and evaluation of cost-effectiveness. Finally, the long term consequences of PARP inhibitors, including the risk of myelodysplasia and acute myeloid leukemia need to be quantified in ongoing large phase III clinical trials.

The current status of PARP inhibitors in ovarian cancer.

Recent advances in our understanding of the molecular biology of epithelial ovarian cancer have led to the development of a number of targeted therapies, including poly-ADP-ribose polymerase (PARP) inhibitors. PARP inhibitors are a novel class of therapeutic agents that target tumors with deficiencies in the homologous recombination DNA repair pathway. Early studies have shown significant efficacy for PARP inhibitors in patients with germline BRCA1/2 mutations. It has become evident that BRCA wild-type patients with other defects in the homologous recombination repair pathway benefit from this therapeutic approach. Importantly, companion homologous recombination deficiency scores are being developed to help guide the selection of patients most likely to gain clinical benefit from PARP inhibition. Olaparib, the first and most extensively investigated PARP inhibitor, is now licensed in Europe for maintenance treatment of patients with platinum-sensitive relapsed BRCA-mutated (germline or somatic) high-grade serous ovarian cancer who have responded to platinum-based chemotherapy. In the United States, olaparib is licensed for treatment of patients with germline BRCA-mutated ovarian cancer who have received 3 or more lines of chemotherapy. There are a number of other PARP inhibitors in late phase clinical development in ovarian cancer including rucaparib, niraparib, veliparib, and talazoparib. This review will focus on the current evidence for PARP inhibitors in ovarian cancer and discuss ongoing clinical trials and future research directions in this rapidly evolving area.

Targeting the mitogen-activated protein kinase pathway in low-grade serous carcinoma of the ovary.

Until recently, there has been little change in the management of epithelial ovarian cancer with the majority of women receiving identical systemic therapy, regardless of histological subtype. The heterogeneity of epithelial ovarian cancer is now well established, with distinct subtypes characterized by specific molecular alterations and patterns of clinical behavior. Low-grade serous carcinoma is a rare subtype associated with an indolent biological behavior and inherent resistance to chemotherapy. The mitogen-activated protein kinase pathway plays a prominent role in the pathogenesis of low-grade serous carcinoma, and provides an attractive target for novel therapeutic agents. Selumetinib, a MEK1/2 inhibitor, demonstrates promising efficacy in women with relapsed low-grade serous carcinoma, and further trials of MEK-inhibition are underway. Translational research will be essential to identify predictive biomarkers for this treatment approach.

Targeted agents and combinations in ovarian cancer: where are we now?

Epithelial ovarian cancer is a heterogeneous disease with distinct histological subtypes characterized by different patterns of clinical behaviour. The identification of molecular pathways associated with individual subtypes has fuelled enthusiasm for the development of targeted therapies directed at specific subtypes of ovarian cancer. To date, the most successful targeted therapies in ovarian cancer to have undergone clinical development include anti-angiogenic agents and PARP inhibitors. Other promising areas of development include folate receptor antagonists, MEK and BRAF inhibitors in low-grade serous carcinoma, and immunotherapy. These novel therapeutic agents have the potential to maximize tumor efficacy, minimize toxicity and improve outcomes for women with epithelial ovarian cancer.

Pazopanib in ovarian cancer.

The majority of women with ovarian cancer present with advanced disease, and ultimately relapse following primary surgery and platinum-taxane chemotherapy. Despite recent advances in the development of targeted agents in ovarian cancer, survival rates remain poor. The promising activity of bevacizumab, a VEGF receptor inhibitor, has stimulated research on the use of additional anti-angiogenic agents in ovarian cancer. Pazopanib, an oral tyrosine kinase inhibitor, targets VEGF receptor-1, -2 and -3, platelet-derived growth factor receptor-α and -ß and c-kit; resulting in the inhibition of angiogenesis and tumor proliferation. Early phase studies have demonstrated promising efficacy and tolerability. To date, there has been one Phase III trial of pazopanib in ovarian cancer, demonstrating a progression-free survival benefit in women treated with maintenance pazopanib following primary surgery and systemic therapy. This article summarizes the preclinical and clinical data of pazopanib in ovarian cancer, highlighting future research options for this agent.

Bleomycin-Induced Flagellate Erythema in a Patient Diagnosed with Ovarian Yolk Sac Tumor.

Flagellate linear hyperpigmentation can rarely be caused by the chemotherapy agent, bleomycin. Herein, we describe the case of a 20-year-old woman treated with bleomycin for an ovarian yolk sac tumor and review the prominent features of this form of dermatitis.

Malignant Ovarian Germ Cell Tumors in Postmenopausal Patients: The Royal Marsden Experience and Literature Review.

BACKGROUND: Ovarian germ cell tumors (OGCT) account for 2-5% of ovarian malignancies, with an annual incidence of 1:100,000, and typically occur in young women and adolescents. The yolk sac tumor (YST) is the second most common subtype of OGCTs and has an aggressive phenotype. Their rarity in postmenopausal women has the potential to cause initial diagnostic uncertainty and lead to delayed or sub-optimal treatment. In this article, we report two cases. The first case is a 67-year-old woman with a pure YST and the second refers to a 59-year-old patient with YST with neuroendocrine differentiation. We also review and summarise the current literature. DISCUSSION: YSTs in older women, either in association with ovarian epithelial tumors or without an identifiable epithelial precursor, are a challenging clinical situation. The disease is aggressive and the outcome remains poor. Thirty-seven cases, including the two reported in this article, have been described in the literature to date. 12/ 37 described patients with malignant OGCTs died within 8 months of diagnosis. CONCLUSION: Ovarian cancer with a YST component in postmenopausal women has an aggressive behaviour and adjuvant platinum-based chemotherapy should be considered.

Combined therapeutic benefit of mitochondria-targeted antioxidant, MitoQ10, and angiotensin receptor blocker, losartan, on cardiovascular function.

OBJECTIVE: Mitochondria-derived reactive oxygen species (ROS) play important roles in the development of cardiovascular disease highlighting the need for novel targeted therapies. This study assessed the potential therapeutic benefit of combining the mitochondria-specific antioxidant, MitoQ10, with the low-dose angiotensin receptor blocker (ARB), losartan, on attenuation of hypertension and left ventricular hypertrophy. In parallel, we investigated the impact of MitoQ10 on cardiac hypertrophy in a neonatal cardiomyocyte cell line. METHODS AND RESULTS: Eight-week-old male stroke-prone spontaneously hypertensive rats (SHRSPs, n=8-11) were treated with low-dose losartan (2.5 mg/kg per day); MitoQ10 (500 µmol/l); a combination of MitoQ10 and losartan (M+L); or vehicle for 8 weeks. Systolic pressure and pulse pressure were significantly lower in M+L rats (167.1 ± 2.9 mmHg; 50.2 ± 2.05 mmHg) than in untreated SHRSP (206.6 ± 9 mmHg, P<0.001; 63.7 ± 2.7 mmHg, P=0.001) and demonstrated greater improvement than MitoQ10 or low-dose losartan alone, as measured by radiotelemetry. Left ventricular mass index was significantly reduced from 22.8 ± 0.74 to 20.1 ± 0.61 mg/mm in the combination group (P<0.05). Picrosirius red staining showed significantly reduced cardiac fibrosis in M+L rats (0.82 ± 0.22 A.U.) compared with control (5.94 ± 1.35 A.U., P<0.01). In H9c2 neonatal rat cardiomyocytes, MitoQ10 significantly inhibited angiotensin II mediated hypertrophy in a dose-dependent manner (500  nmol/l MitoQ10 153.7 ± 3.1 microns vs. angiotensin II 200.1 ± 3.6 microns, P<0.001). CONCLUSION: Combining MitoQ10 and low-dose losartan provides additive therapeutic benefit, significantly attenuating development of hypertension and reducing left ventricular hypertrophy. In addition, MitoQ10 mediates a direct antihypertrophic effect on rat cardiomyocytes in vitro. MitoQ10 has potential as a novel therapeutic intervention in conjunction with current antihypertensive drugs.

A ratiometric fluorescent probe for assessing mitochondrial phospholipid peroxidation within living cells.

Mitochondrial oxidative damage contributes to a wide range of pathologies, and lipid peroxidation of the mitochondrial inner membrane is a major component of this disruption. However, despite its importance, there are no methods to assess mitochondrial lipid peroxidation within cells specifically. To address this unmet need we have developed a ratiometric, fluorescent, mitochondria-targeted lipid peroxidation probe, MitoPerOx. This compound is derived from the C11-BODIPY(581/591) probe, which contains a boron dipyromethane difluoride (BODIPY) fluorophore conjugated via a dienyl link to a phenyl group. In response to lipid peroxidation the fluorescence emission maximum shifts from ∼590 to ∼520nm. To target this probe to the matrix-facing surface of the mitochondrial inner membrane we attached a triphenylphosphonium lipophilic cation, which leads to its selective uptake into mitochondria in cells, driven by the mitochondrial membrane potential. Here we report on the development and characterization of MitoPerOx. We found that MitoPerOx was taken up very rapidly into mitochondria within cells, where it responded to changes in mitochondrial lipid peroxidation that could be measured by fluorimetry, confocal microscopy, and epifluorescence live cell imaging. Importantly, the peroxidation-sensitive change in fluorescence at 520nm relative to that at 590nm enabled the use of the probe as a ratiometric fluorescent probe, greatly facilitating assessment of mitochondrial lipid peroxidation in cells.

Specific targeted gene repair using single-stranded DNA oligonucleotides at an endogenous locus in mammalian cells uses homologous recombination.

The feasibility of introducing point mutations in vivo using single-stranded DNA oligonucleotides (ssON) has been demonstrated but the efficiency and mechanism remain elusive and potential side effects have not been fully evaluated. Understanding the mechanism behind this potential therapy may help its development. Here, we demonstrate the specific repair of an endogenous non-functional hprt gene by a ssON in mammalian cells, and show that the frequency of such an event is enhanced when cells are in S-phase of the cell cycle. A potential barrier in using ssONs as gene therapy could be non-targeted mutations or gene rearrangements triggered by the ssON. Both the non-specific mutation frequencies and the frequency of gene rearrangements were largely unaffected by ssONs. Furthermore, we find that the introduction of a mutation causing the loss of a functional endogenous hprt gene by a ssON occurred at a similarly low but statistically significant frequency in wild type cells and in cells deficient in single strand break repair, nucleotide excision repair and mismatch repair. However, this mutation was not induced in XRCC3 mutant cells deficient in homologous recombination. Thus, our data suggest ssON-mediated targeted gene repair is more efficient in S-phase and involves homologous recombination.