PARP inhibitors (PARPi) prolongation after local therapy for oligo-metastatic progression in relapsed ovarian cancer patients.

BACKGROUND: PARP inhibitors (PARPi) have revolutionized the management of high-grade epithelial ovarian cancer (HGOC) treatment. However, a significant number of patients relapse or progress under PARPi, leading to the introduction of a new line of systemic therapy such as chemotherapy. In patients with a limited number of metastatic sites at progression, -referred to as an oligometastatic progression- a potential indication for local therapy followed by re-introduction or continuation of PARPi treatment rather than initiating a new line of chemotherapy could be proposed. However, the impact of such strategies on progression free survival (PFS) in these patients remains unknown. METHODS: This international multicenter retrospective study evaluated the efficacy of PARPi continuation or re-introduction in patients with HGOC after local treatment for oligometastatic progression. The main objective was to assess PFS under PARPi after local therapy (PFS post-LT). Secondary objectives included safety and overall survival (OS). RESULTS: 74 patients were identified in 20 centers between April 2020 and November 2021. 65% of patients were BRCA mutated and 92% had received ≥2 lines of prior systemic chemotherapy before the initial introduction of PARPi. Main progression sites were lymph nodes (42%), peritoneum (27%), liver (16%), other visceral (16%) and abdominal wall (4%). Local therapies included radiotherapy (45%), surgery (43%), both (7%), percutaneous thermal ablation (4%) or chemoembolization (1%). Median PFS post-LT was 11.5 months [95% CI 7.4; 17.2]. After a median follow up of 14.8 months, 6 patients (8.1%) discontinued PARPi due to toxicity. The 1-year overall survival rate was 90.7% [95% CI 79.1; 96.0]. CONCLUSIONS: With close to one year without progression or introduction of a new line of systemic therapy, this study reports the feasibility and potential benefit of this original strategy in patients with oligometastatic progression under PARPi.

Expanding the molecular spectrum of tenosynovial giant cell tumors.

Background: While great advances in clinical and pathological description of tenosynovial giant cell tumors (TGCT) have been made, TGCT molecular heterogeneity represents an ongoing challenge. The canonical oncogenic fusion CSF1::COL6A3 is not systematically observed, suggesting that other oncogenic mechanisms are involved in tumorigenesis. This study aims to explore by RNA sequencing a retrospective series of tumors diagnosed as TGCT, in order to provide a better description of their molecular landscape and to correlate molecular features with clinical data. Methods: We analyzed clinicopathological data and performed whole-exome RNA sequencing on 41 TGCT samples. Results: RNAseq analysis showed significant higher CSF1 and CSF1-R expression than a control panel of 2642 solid tumors. RNA sequencing revealed fusion transcripts in 14 patients including 6 not involving CSF1 and some previously unreported fusions. Unsupervised clustering on the expression profiles issued from this series suggested two distinct subgroups: one composed of various molecular subtypes including CSF1 and FN1 rearranged samples and one composed of four tumors harboring an HMGA2::NCOR2 fusion, suggesting distinct tumor entities. Overall, 15 patients received at least one systemic anti-CSF1R treatment and clinical improvement was observed in 11 patients, including patients from both clusters. Discussion: This study reported molecular heterogeneity in TGCT, contrasting with the clinical and pathological homogeneity and the ubiquitous high CSF1 and CSF1R expression levels. Whether molecular diversity may impact the efficacy of systemic treatments needs to be further investigated.