Rare ovarian tumours: Epidemiology, treatment challenges in and outside a network setting

PURPOSE OF THE REVIEW

More than 50% of all gynaecological cancers can be classified as rare tumours (defined as an annual incidence of <6 per 100,000) and such tumours represent an important challenge for clinicians.

RECENT FINDINGS

Rare cancers account for more than one fifth of all new cancer diagnoses, more than any of the single common cancers alone. Reviewing the RARECAREnet database, some of the tumours occur infrequently, whilst others because of their natural history have a high prevalence, and therefore appear to be more common, although their incidence is also rare. Harmonization of medical practice, guidelines and novel trials are needed to identify rare tumours and facilitate the development of new treatments. Ovarian tumours are the focus of this review, but we comment on other rare gynaecological tumours, as the diagnosis and treatment challenges faced are similar.

FUTURE

This requires European collaboration, international partnerships, harmonization of treatment and collaboration to overcome the regulatory barriers to conduct international trials. Whilst randomized trials can be done in many tumour types, there are some for which conducting even single arm studies may be challenging. For these tumours alternative study designs, robust collection of data through national registries and audits could lead to improvements in the treatment of rare tumours. In addition, concentring the care of patients with rare tumours into a limited number of centres will help to build expertise, facilitate trials and improve outcomes.

Novel membrane-based targets - Therapeutic potential in gynecological cancers

Recent advances have been made in the molecular profiling of gynecological tumors. These discoveries have led to the development of targeted therapies that have the potential to disrupt molecular pathways involved in the oncogenesis or tumor progression. In this review, we highlight areas of recent progress in the field of membrane receptor inhibitors in gynecological malignancies and describe the biological rationale underlying the inhibition of these receptors. We will introduce drug immuno-conjugates, and give an update on the biological rationale and the clinical studies involving agents directed against EGFR, HER3, IGFR, MET, FGFR, NOTCH, and TRAIL. We also discuss the challenge facing these new therapies.

A randomized clinical trial of adjuvant chemotherapy with doxorubicin, ifosfamide, and cisplatin followed by radiotherapy versus radiotherapy alone in patients with localized uterine sarcomas (SARCGYN study). A study of the French Sarcoma Group

BACKGROUND

There is no proven benefit of adjuvant treatment of uterine sarcoma (US). SARCGYN phase III study compared adjuvant polychemotherapy followed by pelvic radiotherapy (RT) (arm A) versus RT alone (arm B) conducted to detect an increase ≥ 20% of 3-year PFS.

METHODS

Patients with FIGO stage ≤ III US, physiological age ≤ 65 years; chemotherapy: four cycles of doxorubicin 50 mg/m&sup2; d1, ifosfamide 3 g/m&sup2;/day d1-2, cisplatin 75 mg/m&sup2; d3, (API) + G-CSF q 3 weeks. Study was stopped because of lack of recruitment.

RESULTS

Eighty-one patients were included: 39 in arm A and 42 in arm B; 52 stage I, 16 stage II, 13 stage III; 53 leiomyosarcomas, 9 undifferenciated sarcomas, 19 carcinosarcomas. Gr 3-4 toxicity during API (/37 patients): thrombopenia (76%), febrile neutropenia (22%) with two toxic deaths; renal gr 3 (1 patient). After a median follow-up of 4.3 years, 41/81 patients recurred, 15 in arm A, 26 in arm B. The 3 years DFS is 55% in arm A, 41% in arm B (P = 0.048). The 3-year overall survival (OS) is 81% in arm A and 69% in arm B (P = 0.41).

CONCLUSION

API adjuvant CT statistically increases the 3 year-DFS of patients with US.

P5-01-07: Identification of SORBS2 as a Candidate Marker To Predict Metastatic Relapse in Breast Cancer

Background

Elucidation of promising cancer biomarkers from gene expression data can provide important insight into the relationship between signaling networks and cancer. SORBS2, sorbin and SH3 domain containing 2, is a multi-adapter protein involved in signal transduction associated to the cytoskeleton and was reported to be strongly repressed in pancreatic and cervical cancers.

Methods: With the purpose of identifying genes involved in metastatic process, we compared gene expression profiling of 19 invasive ovarian cancers and 24 borderline tumors. Prognostic value of the selected genes was then tested in a gene expression array database that includes 1659 patients with early breast cancer (Gyorffy B et al. 2010). Upon isolation of SORBS2 as a predictor, its involvement in cell migration and tumor progression was investigated in vitro. Small interfering RNA targeting SORBS2 was used to downregulate its expression in T47D and Hela, two cell lines overexpressing SORBS2. Functional effect of siRNA-induced knockdown of SORBS2 on cell viability was determined by WST-1 assay and Trypan Blue exclusion test. Effect on cell migration was evaluated by wound-healing and transwell assays. Western blot analyses were also performed to examine the expressions of proteins involved in cell survival, death and migration.

Results: High-throughput analyses of genes that are differentially expressed between borderline ovarian tumors and invasive carcinoma demonstrated that SORBS2 is significantly downregulated in invasive carcinoma (FDR&lt;10e-10). Moreover, SORBS2 loss was a strong predictor of relapse in a gene expression array dataset of 1659 patients presenting an early breast cancer (HR=0.62, 0.52−0.72, p=6.4e-10). In vitro studies showed that SORBS2 specific downregulation stimulated cell proliferation, by an average of 40%, in T47D and Hela cell lines. SORBS2 knockdown had no effect on either cell migration rate or protein expressions of p-FAK and p-Paxillin, two focal adhesion proteins which are critical to cell adhesion and migration. No significant variations in protein expressions of Akt/mTOR pro-survival or caspases activation pathways were observed. Gene expression profiling before and after SORBS2 dowregulation is ongoing in the two cell lines.

Conclusion: This study is the first to provide evidence for an antiproliferative activity of SORBS2 with no effect on cell migration in breast cancer cells. Our clinical and in vitro data suggest that SORBS2 is a candidate marker to predict relapse in patients with early breast cancer. Molecular mechanisms mediating the antiproliferative effect of SORBS2 are currently being investigated.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-07.