Challenges in Pharmacokinetic Modelling of [18F]fluoro-PEG-folate PET/CT Imaging in Epithelial Ovarian Cancer Patients.

PURPOSE: To describe the pharmacokinetic properties of the [18F]fluoro-polyethylene glycol(PEG)-folate radiotracer in PET/CT imaging of patients with advanced stage epithelial ovarian cancer (EOC). PROCEDURES: In five patients with advanced EOC (FIGO stage IIIB/IIIC, Fédération Internationale de Gynécologie et d'Obstétrique), a 90-min dynamic PET acquisition of the pelvis was performed directly after i.v. administration of 185 MBq [18F]fluoro-PEG6-folate. Arterial blood samples collected at nineteen timepoints were used to determine the plasma input function. A static volume of interest (VOI) for included tumor lesions was drawn manually on the PET images. Modelling was performed using PMOD software. Three different models (a 1-tissue compartment model (1T2k) and two 2-tissue compartment models, irreversible (2T3k) and reversible (2T4k)) were compared in goodness of fit with the time activity curves by means of the Akaike information criterion. RESULTS: The pharmacokinetic analysis in the pelvic area has proven to be much more challenging than expected. Only four out of 22 tumor lesions in five patients were considered suitable to perform modelling on. The remaining tumor lesions were inapt due to either low tracer uptake, small size, proximity to other [18F]fluoro-PEG6-folate -avid structures and/or displacement by abdominal organ motion in the dynamic scan. Data from the four analyzed tumor lesions suggest that the irreversible 2T3k may best describe the pharmacokinetics. All 22 lesions were immunohistochemically stained positive for the folate receptor alpha (FRα) after resection. CONCLUSION: Performing pharmacokinetic analysis in the abdominal pelvic region is very challenging. This brief article describes the challenges and pitfalls in pharmacokinetic analysis of a tracer with high physiological accumulation in the intestines, in case of lesions of limited size in the abdominal pelvic area.

Cytoreductive surgery for advanced epithelial ovarian cancer in the poly(ADP-ribose) polymerase inhibitors era-Is it time for a new paradigm shift? A systematic review and meta-analysis.

INTRODUCTION: In patients with newly diagnosed advanced high-grade serous and endometrioid epithelial ovarian cancer (EOC) first-line maintenance therapy with poly(ADP-ribose) polymerase inhibitors (PARPi) tremendously improved progression-free survival (PFS). Yet, data on the effect of PARPi in proportion to postoperative residual disease status were lacking. MATERIAL AND METHODS: A systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items of Systematic reviews and Meta-Analysis (PRISMA) guidelines. We searched Medline/Pubmed, Embase and Cochrane databases as well as meeting abstracts until 18th March 2023. Hazard ratios (HRs) alongside their 95% confidence intervals (CIs) for PFS were extracted from the studies. A subgroup analysis was conducted to examine the effect of PARPi according to postoperative residual disease. RESULTS: A total of six phase III randomised controlled trials were included and comprised SOLO 1, PAOLA 1, PRIMA, PRIME, ATHENA-MONO and VELIA. Patients who received PARPi following complete gross resection showed greatest PFS benefit. Compared with placebo, maintenance with PARPi significantly improved PFS in patients with macroscopic residual disease (pooled HR 0.55; 95% CI 0.44-0.68). This magnitude was comparable to that found in patients with complete gross resection (pooled HR 0.53; 95% CI 0.41-0.67). CONCLUSIONS: Patients with macroscopic residual disease benefit from PARPi at the same extent as cases with complete gross resection. However, patients with complete gross resection who were treated with PARPi show the most favourable PFS rates. Hence, the pursuit of achieving complete cytoreduction remains valid in the PARPi era.

Novel Molecular Targets for Tumor-Specific Imaging of Epithelial Ovarian Cancer Metastases.

In epithelial ovarian cancer (EOC), the strongest prognostic factor is the completeness of surgery. Intraoperative molecular imaging that targets cell-surface proteins on tumor cells may guide surgeons to detect metastases otherwise not visible to the naked eye. Previously, we identified 29% more metastatic lesions during cytoreductive surgery using OTL-38, a fluorescent tracer targeting folate receptor-a (FRa). Unfortunately, eleven out of thirteen fluorescent lymph nodes were tumor negative. The current study evaluates the suitability of five biomarkers (EGFR, VEGF-A, L1CAM, integrin avb6 and EpCAM) as alternative targets for molecular imaging of EOC metastases and included FRa as a reference. Immunohistochemistry was performed on paraffin-embedded tissue sections of primary ovarian tumors, omental, peritoneal and lymph node metastases from 84 EOC patients. Tumor-negative tissue specimens from these patients were included as controls. EGFR, VEGF-A and L1CAM were highly expressed in tumor-negative tissue, whereas avb6 showed heterogeneous expression in metastases. The expression of EpCAM was most comparable to FRa in metastatic lesions and completely absent in the lymph nodes that were false-positively illuminated with OTL-38 in our previous study. Hence, EpCAM seems to be a promising novel target for intraoperative imaging and may contribute to a more reliable detection of true metastatic EOC lesions.

Morphological and phenotypical features of ovarian metastases in breast cancer patients.

BACKGROUND: Autotransplantation of frozen-thawed ovarian tissue is a method to preserve ovarian function and fertility in patients undergoing gonadotoxic therapy. In oncology patients, the safety cannot yet be guaranteed, since current tumor detection methods can only exclude the presence of malignant cells in ovarian fragments that are not transplanted. We determined the need for a novel detection method by studying the distribution of tumor cells in ovaries from patients with breast cancer. Furthermore, we examined which cell-surface proteins are suitable as a target for non-invasive tumor-specific imaging of ovarian metastases from invasive breast cancer. METHODS: Using the nationwide database of the Dutch Pathology Registry (PALGA), we identified a cohort of 46 women with primary invasive breast cancer and ovarian metastases. The localization and morphology of ovarian metastases were determined on hematoxylin-and-eosin-stained sections. The following cell-surface markers were immunohistochemically analyzed: E-cadherin, epithelial membrane antigen (EMA), human epidermal growth receptor type 2 (Her2/neu), carcinoembryonic antigen (CEA), αvß6 integrin and epithelial cell adhesion molecule (EpCAM). RESULTS: The majority of ovarian metastases (71%) consisted of a solitary metastasis or multiple distinct nodules separated by uninvolved ovarian tissue, suggesting that ovarian metastases might be overlooked by the current detection approach. Combining the targets E-cadherin, EMA and Her2/neu resulted in nearly 100% detection of ductal ovarian metastases, whereas the combination of EMA, Her2/neu and EpCAM was most suitable to detect lobular ovarian metastases. CONCLUSIONS: Examination of the actual ovarian transplants is recommended. A combination of targets is most appropriate to detect ovarian metastases by tumor-specific imaging.

Prevalence and Risk Factors of Ovarian Metastases in Breast Cancer Patients < 41 Years of Age in the Netherlands: A Nationwide Retrospective Cohort Study.

PURPOSE: Breast cancer is one of the primary indications for cryopreservation and subsequent autotransplantation of ovarian tissue. The safety of this fertility preservation method remains questionable, as the presence of disseminated breast tumor cells cannot yet be excluded in the ovarian autografts. We explored the prevalence of ovarian metastases among young breast cancer patients and determined risk factors for the development of ovarian metastases. METHODS: Using the nationwide database of the Dutch Pathology Registry (PALGA), we identified a cohort of 2648 women with primary invasive breast cancer at age < 41 years in the period 2000-2010 in the Netherlands who subsequently underwent an oophorectomy. From this source population, all cases who had histologically confirmed ovarian metastases were included. For each case of whom clinical data were available, one control without ovarian metastases who matched the time interval between breast cancer diagnosis and oophorectomy was selected. Data were collected on patient characteristics, diagnosis, treatment and follow-up. RESULTS: Ovarian metastases were found in 63 out of 2648 patients who met the inclusion criteria. The risk of developing ovarian metastases increased with time passed since breast cancer diagnosis. Multivariate logistic regression analyses showed significant association between tumor stage and the development of ovarian metastases (p = 0.024). CONCLUSIONS: The prevalence of ovarian metastases was 2.4% among young breast cancer patients. Early ovary removal may reduce the risk of developing ovarian metastases. In breast cancer patients with tumors > 5 cm and/or inflammatory carcinoma, we recommend a cautious approach to ovarian tissue autotransplantation.

Noninvasive Detection of Metastases and Follicle Density in Ovarian Tissue Using Full-Field Optical Coherence Tomography.

PURPOSE: Autotransplantation of ovarian tissue can be used to restore fertility in patients with cancer following gonadotoxic treatment. Whether this procedure is safe remains unclear, as current tumor detection methods render the ovarian tissue unsuitable for transplantation. Full-field optical coherence tomography (FF-OCT) is an imaging modality that rapidly produces high-resolution histology-like images without the need to fix, freeze, or stain the tissue. In this proof-of-concept study, we investigated whether FF-OCT can be used to detect metastases in ovarian tissue, thereby increasing the safety of ovarian tissue autotransplantation. We also evaluated whether cortical ovarian tissue and follicles remain viable following FF-OCT imaging. EXPERIMENTAL DESIGN: Formalin-fixed, paraffin-embedded tissue samples were obtained from seven normal ovaries and fourteen ovaries containing metastases and/or micrometastases. These samples were deparaffinized and imaged using FF-OCT. The FF-OCT images were then compared with corresponding hematoxylin and eosin-stained tissue sections. Finally, we examined the effect of FF-OCT imaging on the viability of ovarian tissues and follicles in fresh bovine ovarian tissue using a glucose uptake and neutral red staining, respectively. RESULTS: FF-OCT illustrated both normal structures and metastases in ovarian tissue within minutes. Primordial follicles were readily identifiable. Finally, tissues and follicles remained viable following FF-OCT imaging for up to 180 and 60 minutes, respectively. CONCLUSIONS: FF-OCT imaging is a promising method for the noninvasive detection of metastases, including micrometastases, in ovarian tissue. Moreover, this method facilitates the selection of cortical ovarian tissue with the highest density of primordial follicles, potentially increasing the likelihood of restoring ovarian function following ovarian tissue autotransplantation. Clin Cancer Res; 22(22); 5506-13. ©2016 AACR.

Identification of cell-surface markers for detecting breast cancer cells in ovarian tissue.

PURPOSE: The safety of ovarian tissue autotransplantation in oncology patients cannot be ensured, as current tumor-detection methods compromise the ovarian tissue viability. Although non-destructive methods (for instance near-infrared fluorescence imaging) can discriminate malignant from healthy tissues while leaving the examined tissues unaffected, they require specific cell-surface tumor markers. We determined which tumor markers are suitable targets for tumor-specific imaging to exclude the presence of breast cancer cells in ovarian tissue. METHODS: Immunohistochemistry was performed on formalin-fixed, paraffin-embedded specimens of ten ovaries from premenopausal patients. Additionally, we screened a tissue microarray containing tumor tissue cores from 24 breast cancer patients being eligible for ovarian tissue cryopreservation. The following cell-surface tumor markers were tested: E-cadherin, EMA (epithelial membrane antigen), Her2/neu (human epidermal growth factor receptor type 2), αvß6 integrin, EpCAM (epithelial cell adhesion molecule), CEA (carcinoembryonic antigen), FR-α (folate receptor-alpha), and uPAR (urokinase-type plasminogen activator receptor). For each tumor, the percentage of positive breast tumor cells was measured. RESULTS: None of the ten ovaries were positive for any of the markers tested. However, all markers (except CEA and uPAR) were present on epithelial cells of inclusion cysts. E-cadherin was present in the majority of breast tumors: ≥90 % of tumor cells were positive for E-cadherin in 17 out of 24 tumors, and 100 % of tumor cells were positive in 5 out of 24 tumors. CONCLUSIONS: Of the markers tested, E-cadherin is the most suitable marker for a tumor-specific probe in ovarian tissue. Methods are required to distinguish inclusion cysts from breast tumor cells.

If the Mountain Does Not Come to Mohammad: The Significance of Guest Operations for Early Stage Ovarian Cancer.

Background: In women with early ovarian cancer (EOC), comprehensive surgical staging is known to enhance ovarian cancer outcomes and requires specific surgical competence. Given that centralization of care remains a topic of continuing debate, a system of "guest operations" was introduced in the midwestern part of The Netherlands. During a guest operation a gynecologic oncologist participates in oncology surgery performed in the community hospital. Objective: This study was conducted to examine the effects of the presence of a gynecologic oncologist on the quality of staging, treatment, and survival in patients with EOC. Materials and Methods: All patients with a pathologically confirmed diagnosis of EOC between January 2000 and December 2009 were selected from a regional cancer registry. Surgical accuracy was checked on the basis of each patient's file, operative notes, and pathology report. Results: A total of 130 patients were included, of whom 15 were treated in the Leiden University Medical Center (LUMC) and 115 in eight regional community hospitals. If a gynecologic oncologist attended the operation, surgical staging was more often adequately performed, 81.1% versus 32.1% when a gynecologic oncologist was not present (p<0.001). Adherence to protocol was observed in 76.9% of operations when a gynecologic oncologist had been present, compared to 49.5% of patients who were treated by a general gynecologist alone (p=0.004). The 5-year disease-free survival was borderline significantly in favor of optimally staged patients, 75.1% in those who were not staged optimally versus 90.9% who were staged optimally (p=0.058). Conclusions: Guest operations deserve a distinguished place among the treatment modalities available to patients with EOC, because surgery by the most specialized and experienced surgeons contributes to better care. (J GYNECOL SURG 30:265).