Abstract A113: National multidisciplinary tumor board improves diagnostic stratification and therapeutic management in cancers of unknown primary
Authors: Bieche Ivan , Kamal Maud , Jacquin Nicolas , Dupain Célia , Guillou Isabelle , Rouleau Etienne , Planchon Julien Masliah , Soubeyran Isabelle , Fouchardière Christelle De La , Tlemsani Camille , Blons Hélène , Marisa Laëtitia , Patrikidou Anna , Escande Fabienne , Blanc Pierre , Wong Jennifer , Saintigny Pierre , Boyault Sandrine , Buisson Adrien , Allory Yves , Vincent-Salomon Anne , Cockenpot Vincent , Selves Janick , Tourneau Christophe Le , Watson Sarah 
Published: December 2023

Introduction: With the increasing complexity of current diagnostic investigations, the integration of clinical, pathological and genomic characteristics is crucial for the management of patients (pts) with cancers of unknown primary (CUP). A national multidisciplinary tumor board (NatCUPMTB) was created in July 2020 in France to discuss the diagnostic and therapeutic management of CUP pts. The objective of this study was to evaluate the diagnostic, prognostic and therapeutic impact of this NatCUPMTB after 30 months of activity.

Methods: This was a multicenter retrospective study with prospective follow-up. All pts discussed at least once in the NatCUPMTB between July 2020 and January 2023 were included. Pts and tumors characteristics, pathological and genomic analyses including WGS, WES and transcriptome analysis performed on the two PFMG2025 (French Genomic Medecine Plan 2025) national sequencing laboratories, multidisciplinary tumor board (MTB) conclusions, and follow-up after MTB were collected.

Results: 151 pts were included. The median age at diagnosis was 58 yo, 55% were female, and the majority of patients had an OMS status &lt;2. The median number of metastatic sites at diagnosis was 2, with a majority located in the lymph nodes (63%). The median time between diagnosis and first MTB presentation was 4 months (1-20). At the time of analysis, NatCUPMTB conclusions and long-term follow up (30 months) were available for 93 pts alive at the second MTB presentation. MTB investigations enabled to identify a likely primary origin in 62/93 (67%) pts, the most frequent being renal carcinoma (N=10), lung carcinoma (N=9) and breast carcinoma (N=8). The most frequently molecular alterations found were in TP53 (37%), KRAS (19%), CDKN2A (18%), NF2 (12%), KMT2C (10%), CDKN2B (9%), PBRM1 (9%) genes. MTB diagnoses were based on the combination of clinical, pathological and genomic investigations in 34/93 (37%) of pts. The others were based on pathological and genomic investigations in 15/93 pts (16%), genomic in 4/93 pts (4%), clinical and genomic in 3/93 pts (3%), clinical and pathological in 3/93 pts (3%) and pathological in 3/93 pts (3%). After a median follow-up of 11.2 months, the median overall survival (OS) was 11.9 months from the 2nd MTB presentation. Importantly, a personalized therapeutic strategy was recommended by NatCUPMTB in 79/93 (85%) of pts. Among these recommendations, 38/79 (49%) were based on the diagnosis of tissue of origin (TOO), 12/79 (15%) on an actionable molecular alteration, 24/79 (30%) on both the TOO and an actionable molecular alteration, and 5/79 (6%) were based on an unguided clinical trial.

Conclusion: NatCUPMTB provides significant diagnostic and therapeutic benefit in 85% of pts with CUP. Early presentation of pts at NatCUPMTB as soon as CUP diagnosis is suspected should be recommended.

Citation Format: Ivan Bieche, Maud Kamal, Nicolas Jacquin, Célia Dupain, Isabelle Guillou, Etienne Rouleau, Julien Masliah Planchon, Isabelle Soubeyran, Christelle De La Fouchardière, Camille Tlemsani, Hélène Blons, Laëtitia Marisa, Anna Patrikidou, Fabienne Escande, Pierre Blanc, Jennifer Wong, Pierre Saintigny, Sandrine Boyault, Adrien Buisson, Yves Allory, Anne Vincent-Salomon, Vincent Cockenpot, Janick Selves, Christophe Le Tourneau, Sarah Watson. National multidisciplinary tumor board improves diagnostic stratification and therapeutic management in cancers of unknown primary [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A113.