Computational modeling of ovarian cancer dynamics suggests optimal strategies for therapy and screening

Heterogeneity and treatment landscape of ovarian carcinoma

Ovarian carcinoma is characterized by heterogeneity at the molecular, cellular and anatomical levels, both spatially and temporally. This heterogeneity affects response to surgery and/or systemic therapy, and also facilitates inherent and acquired drug resistance. As a consequence, this tumour type is often aggressive and frequently lethal. Ovarian carcinoma is not a single disease entity and comprises various subtypes, each with distinct complex molecular landscapes that change during progression and therapy. The interactions of cancer and stromal cells within the tumour microenvironment further affects disease evolution and response to therapy. In past decades, researchers have characterized the cellular, molecular, microenvironmental and immunological heterogeneity of ovarian carcinoma. Traditional treatment approaches have considered ovarian carcinoma as a single entity. This landscape is slowly changing with the increasing appreciation of heterogeneity and the recognition that delivering ineffective therapies can delay the development of effective personalized approaches as well as potentially change the molecular and cellular characteristics of the tumour, which might lead to additional resistance to subsequent therapy. In this Review we discuss the heterogeneity of ovarian carcinoma, outline the current treatment landscape for this malignancy and highlight potentially effective therapeutic strategies in development.

Selection of maintenance therapy during first-line treatment of advanced ovarian cancer based on pharmacologic characteristics

INTRODUCTION

Maintenance therapy with bevacizumab and the poly (ADP-ribose) polymerase (PARP) inhibitors olaparib and niraparib after first-line treatment of advanced ovarian cancer has been approved. However, it is not clear which one should be used for which patients.

AREAS COVERED

This paper presents a detailed analysis of data from phase 3 trials in ovarian cancer evaluating bevacizumab (ICON7, GOG-0218), olaparib (SOLO1, PAOLA-1), and niraparib (PRIMA, PRIME). We will discuss how the results of these trials relate to the 'rebound effect,' in which the risk of progression increases after discontinuation of bevacizumab in patients receiving bevacizumab, and to the significant difference in tissue permeability between olaparib and niraparib.

EXPERT OPINION

In patients with homologous recombination deficiency and no macroscopic residual disease (R0) after primary debulking surgery (PDS), the combination of bevacizumab plus olaparib seems to be the best regimen. Olaparib monotherapy is suitable for patients with BRCA mutations other than PDS R0. Bevacizumab is most useful in cases with a short duration of the rebound effect, i.e. short survival. Niraparib is useful in others but may be more useful in Asians.

Adaptive therapy for ovarian cancer: An integrated approach to PARP inhibitor scheduling

Toxicity and emerging drug resistance are important challenges in PARP inhibitor (PARPi) treatment of ovarian cancer. Recent research has shown that evolutionary-inspired treatment algorithms which adapt treatment to the tumor's treatment response (adaptive therapy) can help to mitigate both. Here, we present a first step in developing an adaptive therapy protocol for PARPi treatment by combining mathematical modelling and wet-lab experiments to characterize the cell population dynamics under different PARPi schedules. Using data from in vitro Incucyte Zoom time-lapse microscopy experiments and a step-wise model selection process we derive a calibrated and validated ordinary differential equation model, which we then use to test different plausible adaptive treatment schedules. Our model can accurately predict the in vitro treatment dynamics, even to new schedules, and suggests that treatment modifications need to be carefully timed, or one risks losing control over tumour growth, even in the absence of any resistance. This is because our model predicts that multiple rounds of cell division are required for cells to acquire sufficient DNA damage to induce apoptosis. As a result, adaptive therapy algorithms that modulate treatment but never completely withdraw it are predicted to perform better in this setting than strategies based on treatment interruptions. Pilot experiments in vivo confirm this conclusion. Overall, this study contributes to a better understanding of the impact of scheduling on treatment outcome for PARPis and showcases some of the challenges involved in developing adaptive therapies for new treatment settings.

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.

Evolutionary perspectives, heterogeneity and ovarian cancer: a complicated tale from past to present

Ovarian cancer is composed of a complex system of cells best described by features such as clonal evolution, spatial and temporal genetic heterogeneity, and development of drug resistance, thus making it the most lethal gynecologic cancer. Seminal work on cancer as an evolutionary process has a long history; however, recent cost-effective large-scale molecular profiling has started to provide novel insights coupled with the development of mathematical algorithms. In the current review, we have systematically searched for articles that focused on the clonal evolution of ovarian cancer to offer the whole landscape of research that has been done and highlight future research avenues given its characteristic features and connections to evolutionary biology.

Individualization in the first-line treatment of advanced ovarian cancer based on the mechanism of action of molecularly targeted drugs

With the development of poly(ADP-ribose) polymerase inhibitors, the treatment of advanced ovarian cancer is changing dramatically. The purpose of this narrative review is to provide a direction for the individualization of advanced ovarian cancer treatment based on the mechanism of action of molecularly targeted drugs currently used in Japan. The PAOLA-1 study showed very good progression-free survival in patients with homologous recombination deficiency tumors who underwent complete surgery with primary debulking surgery and who received olaparib plus bevacizumab. Niraparib has high intratumor penetration, and in a subgroup analysis of the PRIMA study, it was most effective in patients with residual tumors after interval debulking surgery. These data suggest the importance of achieving complete surgery and aiming for cure in the treatment of ovarian cancer and how the use of bevacizumab, olaparib, and niraparib should be individualized.

The roles and limitations of bevacizumab in the treatment of ovarian cancer

Bevacizumab, an anti-VEGF antibody, targets mainly tumor blood vessels and exerts a cytostatic antitumor effect. In primary ovarian cancer, bevacizumab is used for 15 months, but its effect on progression-free survival disappears after 2 years and does not prolong overall survival. And in the treatment of primary ovarian cancer, there is no evidence that bevacizumab increases the intratumor concentration of chemotherapy and enhances response rates. On the other hand, bevacizumab is not affected by resistance mechanisms to chemotherapeutic agents or poly(ADP-ribose) polymerase (PARP) inhibitors. In the era of using PARP inhibitors for primary ovarian cancer, bevacizumab will become a molecularly targeted drug that will play a central role in chemo-refractory and recurrent ovarian cancer.

Perspectives on Ovarian Cancer 1809 to 2022 and Beyond

Unlike many other malignancies, overall survival for women with epithelial ovarian cancer has improved only modestly over the last half-century. The perspectives presented here detail the views of a gynecologic oncologist looking back and the view of the academic editor looking forward. Surgical beginnings in 1809 are merged with genomics, surgical advances, and precision therapy at present and for the future. Presentations in this special issue focus on factors related to the diagnosis of ovarian cancer: (1) markers for the preoperative assessment of primary and metastatic ovarian tumors, (2) demonstrations of the presence of pelvic fluid in ultrasound studies of ovarian malignancies, (3) the effects of age, menopausal status, and body habitus on ovarian visualization, (4) the ability of OVA1 to detect ovarian cancers when Ca125 was not informative, (5) the detection of tumor-specific changes in cell adhesion molecules by tissue-based staining, (6) presentation of a high discrimination model for ovarian cancer using IOTA Simple Rules and CA125, (7) review of low-grade serous carcinoma of the ovary, and (8) a comprehensive case report on ovarian carcinosarcoma.

Significance of Pelvic Fluid Observed during Ovarian Cancer Screening with Transvaginal Sonogram

The primary objective was to examine the role of pelvic fluid observed during transvaginal ultrasonography (TVS) in identifying ovarian malignancy. A single-institution, observational study was conducted within the University of Kentucky Ovarian Cancer Screening trial from January 1987 to September 2019. We analyzed true-positive (TP), false-positive (FP), true-negative (TN), and false-negative (FN) groups for the presence of pelvic fluid during screening encounters. Measured outcomes were the presence and duration of fluid over successive screening encounters. Of the 48,925 women surveyed, 2001 (4.1%) had pelvic fluid present during a TVS exam. The odds ratio (OR) of detecting fluid in the comparison group (TN screen; OR = 1) significantly differed from that of the FP cases (benign pathology; OR: 13.4; 95% confidence interval (CI): 9.1–19.8), the TP cases with a low malignant potential (LMP; OR: 28; 95% CI: 26.5–29.5), TP ovarian cancer cases (OR: 50.4; 95% CI: 27.2–93.2), and FN ovarian cancer cases (OR: 59.3; 95% CI: 19.7–178.1). The mean duration that pelvic fluid was present for women with TN screens was 2.2 ± 0.05 encounters, lasting 38.7 ± 1.3 months. In an asymptomatic screening population, free fluid identified in TVS exams was more associated with ovarian malignancy than in the control group or benign ovarian tumors. While pelvic free fluid may not solely discriminate malignancy from non-malignancy, it appears to be clinically relevant and warrants thoughtful consideration.