Vena cava leiomyosarcoma surgery results in a retrospective cohort of 41 patients from two centers.

BACKGROUND: Leiomyosarcoma of the vena cava (LMS-VC) is a rare entity with poor oncological outcomes and a lack of histological staging prognostic factors. METHODS: Outcomes of consecutive patients operated on LMS-VC between March 2003 and May 2022, in two specialized sarcoma centers were reported. RESULT: Forty-one patients were identified. Median size of LMS-VC was 9 cm with 68% of complete obstruction. After surgery, severe complication rate was 30%. No postoperative mortality was reported. Microscopic complete excision was obtained for 71% of patients, R1 for 27% and one patient presented an R2 resection. Grade 3 was found in 24%. After a median follow-up of 70 months, 3 years disease-free survival (DFS) and 5 years DFS were 34% and 17%, and 3 years overall survival (OS) and 5 years OS were 74% and 50%. Distant metastasis concerned 54% of recurrences, local 7% and local and distant 5%. Multivariate analysis showed that FNCLCC grade (p < 0.001) and perioperative chemotherapy (p = 0.026) were significant factors for DFS. In multivariate analysis, FNCLCC grade was a significant factor for OS (p = 0.004). DISCUSSION: Perioperative chemotherapy may have a role to play in lowering the risk of recurrence for LMS-VC, particularly in high-grade tumor.

Initial laparoscopic liver resection is associated with reduced adhesions and transfusions at the time of salvage liver transplantation.

BACKGROUND: Laparoscopic liver resection (LLR) has been associated with improved patient recovery as well as reduced postoperative adhesions compared to open LR (OLR) and could therefore facilitate redo liver surgery. LLR prior to liver transplantation (LT) is increasingly performed, LT being saved for HCC recurrence. LT is still performed by open surgery due to vascular reconstructions and underlying liver chronic disease. We evaluated the impact of laparoscopic approach for LR prior to LT in terms of intraoperative transfusions, adhesions severity and outcome. METHODS: Data from all patients who underwent a LT after LR in two French high-volume tertiary centers were retrospectively reviewed. The impact of LLR on per operative and postoperative outcome was assessed using logistic regression. RESULTS: 170 patients were included, 43 patients in the LLR group and 127 in the OLR group. Preoperative characteristics were comparable between both groups, except LLR group included more patients with "very early-stage" BCLC tumors than OLR group (51% vs. 33%, p = 0.02) and less anatomical resections (54% vs. 75%, p = 0.015). During LT, the transfusion rate was significantly higher in the OLR group (71.4% vs 44.2%, p = 0.002) as well as the proportion of type III adhesions according to OLSG classification (p < 0.001). Multivariate analysis found LLR to be an independent protective factor for adhesions and transfusion (p = 0.001 and p = 0.03 respectively). CONCLUSION: Laparoscopic liver resection was associated with reduced postoperative adhesions and transfusion requirements during subsequent liver transplantation.

Single-cell multiomics profiling reveals heterogeneous transcriptional programs and microenvironment in DSRCTs.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive sarcoma driven by the EWSR1::WT1 chimeric transcription factor. Despite this unique oncogenic driver, DSRCT displays a polyphenotypic differentiation of unknown causality. Using single-cell multi-omics on 12 samples from five patients, we find that DSRCT tumor cells cluster into consistent subpopulations with partially overlapping lineage- and metabolism-related transcriptional programs. In vitro modeling shows that high EWSR1::WT1 DNA-binding activity associates with most lineage-related states, in contrast to glycolytic and profibrotic states. Single-cell chromatin accessibility analysis suggests that EWSR1::WT1 binding site variability may drive distinct lineage-related transcriptional programs, supporting some level of cell-intrinsic plasticity. Spatial transcriptomics reveals that glycolytic and profibrotic states specifically localize within hypoxic niches at the periphery of tumor cell islets, suggesting an additional role of tumor cell-extrinsic microenvironmental cues. We finally identify a single-cell transcriptomics-derived epithelial signature associated with improved patient survival, highlighting the clinical relevance of our findings.

Correlation between peritoneal cancer index and survival in advanced epithelial ovarian cancer with complete resection.

OBJECTIVE: The aim of this study was to investigate the relation between the peritoneal cancer index, overall survival, and recurrence free survival, in patients with epithelial ovarian cancer. METHODS: Patients treated at the Gustave-Roussy Institute between December 2004 and November 2017 for advanced epithelial ovarian cancer in complete resection were included. The correlation between the peritoneal cancer index and survival was studied using statistical modeling. Multivariate analysis was performed with a logistic regression model. RESULTS: Of the 351 patients included, 94 (27%) had initial surgery and 257 (73%) had interval surgery. Median follow-up was 52.7 months (range 47.6-63.9). Median peritoneal cancer index was 10 (range 0-32). The linear model best represented the relationship between peritoneal cancer index and overall survival. Patients with neoadjuvant chemotherapy had a greater instantaneous risk of baseline death than those with initial surgery, as well as a more rapid increase in this risk as the peritoneal cancer index increased. Overall survival and recurrence free survival were better in the initial surgery group (103.4 months (79.1-not reached (NR)) vs 66.5 months (59.1-95.3) and 31.8 months (23.7-48.7) vs 25.9 months (23.2-29), respectively). Risk factors for death were body mass index, peritoneal cancer index, and need for neoadjuvant chemotherapy. CONCLUSION: The peritoneal cancer index is a prognostic indicator, but its linear relationship with survival precluded setting a unique peritoneal cancer index cut-off. Moreover, the prognostic impact of peritoneal cancer index was stronger in the setting of neoadjuvant chemotherapy.

Impact of lymphovascular invasion on otherwise low-risk papillary thyroid carcinomas: a retrospective and observational study.

PURPOSE: Presence of venous vascular invasion is a criterion of intermediate risk of recurrence in papillary thyroid carcinoma (PTC). However, the presence and type of vascular invasion (lymphatic or venous) is often underreported and its impact on PTCs without other risk features remains unknown. The aim of this study was to evaluate the impact of both lymphatic and venous invasion on the risk of recurrence/persistence on otherwise low-risk PTCs. METHODS: Retrospective study including patients with otherwise low-risk PTCs but with vascular invasion, diagnosed between 2013 and 2019. The persistence/recurrence during the follow-up was evaluated. Pathology was reviewed to confirm the presence of lymphovascular invasion and determine the type of invasion. RESULTS: A total of 141 patients were included. Lymphovascular invasion was confirmed in 20.6%. After surgery, 48.9% (N = 69) of the patients received radioactive iodine (RAI). The median follow-up time was 4 [3-6] years. Overall, 6 (4.2%) patients experienced persistent/recurrent disease in the neck, including 3 with lymphovascular invasion, confirmed as "only lymphatic". Overall, patients with tumors harboring lymphovascular invasion had sensibly more persistent/recurrence disease compared with those without lymphovascular invasion (10.3% vs 2.7%, p = 0.1), especially in the subgroup of patients not treated with RAI (20% vs 1.6%, p = 0.049) [OR 15.25, 95% CI 1.24-187.85, p = 0.033]. CONCLUSION: Lymphovascular invasion, including lymphatic invasion only, is associated with a sensibly higher risk of persistent/recurrent disease in otherwise low-risk PTCs, namely in patients not treated with RAI. Lymphatic invasion could have a role in risk-stratification systems for decision making.

Desmoid-type fibromatosis: Current therapeutic strategies and future perspectives.

Desmoid tumors (DT) are rare, slow-growing, locally invasive soft tissue tumors that often pose significant therapeutic challenges. Traditional management strategies including active surveillance, surgery, radiotherapy, and systemic therapy which are associated with varying recurrence rates and high morbidity. Given the challenging nature of DT and the modest outcomes associated with current treatment strategies, there has been a growing interest in the field of γ-secretase inhibitors as a result of its action on the Wnt/ß-catenin signaling pathway. In this review article, we will shed the light on the pathogenesis and molecular biology of DT, discuss its symptoms and diagnosis, and provide a comprehensive review of the traditional therapeutic approaches. We will also delve into the mechanisms of action of γ-secretase inhibitors, its efficacy, and the existing preclinical and clinical data available to date on the use of these agents, as well as the potential challenges and future prospects in the treatment landscape of these tumors.

Hepatic arterial oxaliplatin plus intravenous 5-fluorouracil and cetuximab for first-line treatment of colorectal liver metastases: A multicenter phase II trial.

BACKGROUND: The efficacy and tolerability of hepatic arterial infusion (HAI) oxaliplatin plus systemic 5-fluorouracil and cetuximab as frontline treatment in patients with colorectal liver metastases (CRLM) are unknown. METHODS: In this multicenter, single-arm phase II study, patients with CRLM not amenable to curative-intent resection or requiring complex/major liver resection, and no prior chemotherapy for metastatic disease, received HAI oxaliplatin and intravenous 5-fluorouracil, leucovorin and cetuximab, every two weeks until disease progression, limiting toxicity or at least 3 months after complete response or curative-intent resection/ablation. The primary endpoint was overall response rate (ORR). RESULTS: 35 patients, mostly with bilateral (89%), multiple CRLM (>4, 86%; >10, 46%) were enrolled in eight centers. The ORR was 88% (95% CI, 71%-96%) among evaluable patients (n = 32), and 95% (95% CI 70-100%) among the 22 wild-type RAS/BRAF evaluable patients. After a median follow-up of 8.8 years (95% CI, 8.7-not reached), median progression-free survival was 17.9 months (95% CI, 15-23) and median overall survival (OS) was 46.3 months (95% CI, 40.0-not reached). 23 of the 35 patients (66%), including 22 (79%) of the 25 patients with wild-type RAS tumor, underwent curative-intent surgical resection and/or ablation of CRLM. HAI catheter remained patent in 86% of patients, allowing for a median of eight oxaliplatin infusions (range, 1-19). Treatment toxicity was manageable, without toxic death. CONCLUSION: HAI oxaliplatin plus systemic 5-fluorouracil and cetuximab appears highly effective in the frontline treatment of patients with unresectable CRLM and should be investigated further.

The Need for Centralization for Small Intestinal Neuroendocrine Tumor Surgery: A Cohort Study from the GTE-Endocan-RENATEN Network, the CentralChirSINET Study.

BACKGROUND: The concept of surgical centralization is becoming more and more accepted for specific surgical procedures. OBJECTIVE: The aim of this study was to evaluate the relationship between procedure volume and the outcomes of surgical small intestine (SI) neuroendocrine tumor (NET) resections. METHODS: We conducted a retrospective national study that included patients who underwent SI-NET resection between 2019 and 2021. A high-volume center (hvC) was defined as a center that performed more than five SI-NET resections per year. The quality of the surgical resections was evaluated between hvCs and low-volume centers (lvCs) by comparing the number of resected lymph nodes (LNs) as the primary endpoint. RESULTS: A total of 157 patients underwent surgery in 33 centers: 90 patients in four hvCs and 67 patients in 29 lvCs. Laparotomy was more often performed in hvCs (85.6% vs. 59.7%; p < 0.001), as was right hemicolectomy (64.4% vs. 38.8%; p < 0.001), whereas limited ileocolic resection was performed in 18% of patients in lvCs versus none in hvCs. A bi-digital palpation of the entire SI length (95.6% vs. 34.3%, p < 0.001), a cholecystectomy (93.3% vs. 14.9%; p < 0.001), and a mesenteric mass resection (70% vs. 35.8%; p < 0.001) were more often performed in hvCs. The proportion of patients with ≥8 LNs resected was significantly higher (96.3% vs. 65.1%; p < 0.001) in hvCs compared with lvCs, as was the proportion of patients with ≥12 LNs resected (87.8% vs. 52.4%). Furthermore, the number of patients with multiple SI-NETs was higher in the hvC group compared with the lvC group (43.3% vs. 25.4%), as were the number of tumors in those patients (median of 7 vs. 2; p < 0.001). CONCLUSIONS: Optimal SI-NET resection was significantly more often performed in hvCs. Centralization of surgical care of SI-NETs is recommended.

Systemic Therapy in Advanced Pleomorphic Liposarcoma: a Comprehensive Review.

OPINION STATEMENT: The therapeutic approach of pleomorphic liposarcoma (PLPS), a rare high-grade subgroup of soft tissue sarcoma, is commonly extrapolated from the management of other LPS subtypes. Only published retrospective data on PLPS currently serve as a guide for oncologists without clear recommendations or specific guidelines. In the advanced setting, specific systemic therapy such as eribulin and trabectedin showed promising activity in comparison to conventional therapy (doxorubicin- and gemcitabine-based protocols), which currently remains the current standard of care at initial stages of the disease. The better understanding of soft tissue sarcoma (STS) pathophysiology and disease course has led to the development of adapted clinical trial designs for rare STS histotypes with specific treatment approach.

[French recommendations for malignant pheochromocytomas and paragangliomas by the national ENDOCAN-COMETE network]. / Recommandations du réseau national ENDOCAN-COMETE pour la prise en charge des phéochromocytomes et paragangliomes métastatiques.

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors, developed respectively in the adrenal medulla and in extra-adrenal locations. Their malignancy is defined by the presence of distant metastases. Forty percent of them are inherited and can be part of different hereditary syndromes. Their management is ensured in France by the multidisciplinary expert centers of the ENDOCAN-COMETE national network "Cancers of the Adrenal gland", certified by the National Cancer Institute and discussed within multidisciplinary team meetings. The diagnostic and therapeutic work-up must be standardized, based on an expert analysis of clinical symptoms, hormonal biological secretions, genetics, morphological and specific metabolic imaging. In the context of a heterogeneous survival sometimes beyond seven to ten years, therapeutic intervention must be justified. This is multidisciplinary and relies on surgery, interventional radiology, external or internal radiotherapy and medical treatments such as sunitinib or dacarbazine and temodal chemotherapy. The personalized approach based on functional imaging fixation status and genetics is progressing despite the extreme rarity of this disease.

Individual Participant Data Network Meta-Analysis of Neoadjuvant Chemotherapy or Chemoradiotherapy in Esophageal or Gastroesophageal Junction Carcinoma.

PURPOSE: The optimal neoadjuvant treatment for resectable carcinoma of the thoracic esophagus (TE) or gastroesophageal junction (GEJ) remains a matter of debate. We performed an individual participant data (IPD) network meta-analysis (NMA) of randomized controlled trials (RCTs) to study the effect of chemotherapy or chemoradiotherapy, with a focus on tumor location and histology subgroups. PATIENTS AND METHODS: All, published or unpublished, RCTs closed to accrual before December 31, 2015 and having compared at least two of the following strategies were eligible: upfront surgery (S), chemotherapy followed by surgery (CS), and chemoradiotherapy followed by surgery (CRS). All analyses were conducted on IPD obtained from investigators. The primary end point was overall survival (OS). The IPD-NMA was analyzed by a one-step mixed-effect Cox model adjusted for age, sex, tumor location, and histology. The NMA was registered in PROSPERO (CRD42018107158). RESULTS: IPD were obtained for 26 of 35 RCTs (4,985 of 5,807 patients) corresponding to 12 comparisons for CS-S, 12 for CRS-S, and four for CRS-CS. CS and CRS led to increased OS when compared with S with hazard ratio (HR) = 0.86 (0.75 to 0.99), P = .03 and HR = 0.77 (0.68 to 0.87), P < .001 respectively. The NMA comparison of CRS versus CS for OS gave a HR of 0.90 (0.74 to 1.09), P = .27 (consistency P = .26, heterogeneity P = .0038). For CS versus S, a larger effect on OS was observed for GEJ versus TE tumors (P = .036). For the CRS versus S and CRS versus CS, a larger effect on OS was observed for women (P = .003, .012, respectively). CONCLUSION: Neoadjuvant chemotherapy and chemoradiotherapy were consistently better than S alone across histology, but with some variation in the magnitude of treatment effect by sex for CRS and tumor location for CS. A strong OS difference between CS and CRS was not identified.

Robotic-assisted surgery for mid and low rectal cancer: a long but safe learning curve.

The number of robotic-assisted procedures for rectal cancer is rising. The risk of this procedure when performed by surgeon with limited robotic experience is unknown and the precise duration of the learning curve debated. We, therefore, aimed to analyze the learning curve and its related safety in a single center before the development of mentoring programs. We prospectively recorded all robotic procedures performed for colorectal cancer between 2015 and 2020 by a single surgeon. Operative times for partial and total proctectomy were analyzed. The learning curve was defined by comparison with the standard duration of the laparoscopic procedure performed in expert centers (published in GRECCAR 5 and GRECCAR 6 trials) and calculated using a cumulative summation for learning curve test (LC-CUSUM). Among the 174 patients operated for colorectal cancer, we analyzed the outcomes of the 89 patients operated by partial and total robotic proctectomy. To reach repeatedly the same surgical duration as laparoscopic procedure for partial or complete proctectomy, the LC-CUSUM identified a learning curve of 57 patients. A severe morbidity in this population, defined by Clavien-Dindo classification ≥ 3, was observed in 15 cases (16.8%) with an anastomotic leak rate of 13.5%. The rate of completeness of mesorectal excision was 90% and the mean number of harvested lymph nodes was 15 (± 9). Using operative time as end-point, the learning curve of rectal cancer robotic surgery identified a cut-off of 57 patients. The technic remained safe with acceptable morbidity and oncological outcomes.

[Guidelines of the French National ENDOCAN-COMETE, Association of Endocrine Surgery, Society of Urology for the management of adrenocortical carcinoma]. / Recommandations conjointes du réseau National ENDOCAN-COMETE, de l'Association francophone de chirurgie endocrinienne et de la Société française d'urologie pour la prise en charge du carcinome corticosurrénalien.

The adrenocortical carcinoma (ACC) is a primary malignant tumor developed from the adrenal cortex, defined by a Weiss score≥3. Its prognosis is poor and depends mainly on the stage of the disease at diagnosis. Care is organized in France by the multidisciplinary expert centers of the national ENDOCAN-COMETE "Adrenal Cancers" network, certified by the National Cancer Institute. This document updates the guidelines for the management of ACC in adults based on the most robust data in the literature. It's divided into 11 chapters: (1) circumstances of discovery; (2) pre-therapeutic assessment; (3) diagnosis of ACC; (4) oncogenetics; (5) prognostic classifications; (6) treatment of hormonal hypersecretion; (7) treatment of localized forms; (8) treatment of relapses; (9) treatment of advanced forms; (10) follow-up; (11) the particular case of ACC and pregnancy. R0 resection of all localized ACC remains an unmet need and it must be performed in expert centers. Flow-charts for the therapeutic management of localized ACC, relapse or advanced ACC are provided. It was written by the experts from the national ENDOCAN-COMETE network and validated by all French Societies involved in the management of these patients (endocrinology, medical oncology, endocrine surgery, urology, pathology, genetics, nuclear medicine, radiology, interventional radiology).

Molecular profiling and target actionability for precision medicine in neuroendocrine neoplasms: real-world data.

BACKGROUND: Key molecular alterations (MA) of neuroendocrine neoplasm (NEN) of various grade/primaries have been described but the applicability of molecular profiling (MP) for precision medicine in NEN remains to be demonstrated. METHODS: We conducted a retrospective study of all patients with metastatic NEN who had MP on tumour tissue at Gustave Roussy. The primary objective was to assess the clinical applicability of MP by evaluating the growth modulator index (GMI) as the primary end-point. RESULTS: MPs were obtained in 114 out of 156 eligible patients, including 12% NET-G1, 42% NET-G2, 13% NET-G3 and 35% neuroendocrine carcinoma (NEC). Primary sites were lung/thymus (40%), pancreas (19%), gastro-intestinal (16%), head&neck (10%), unknown (10%) and others (10%) with synchronous metastases in 61% of the patients. Most frequent MA were: MEN1 (25%), PTEN (13%), TP53 (11%) and TSC2 (9%), in neuroendocrine tumour (NET), and TP53 (50%) and RB1 (18%) in NEC. ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) classification of these MA were: I(5%), III(20%), IV(23%), X(27%); a putative actionable MA was identified in 48% patients. Median TMB was 5.7 Mut/Mb, with 3 TMB > 10 and 1 MSI NET. No MA was found in 26% patients. Molecularly matched treatment was administered to 19 patients (4 NEC, 15 NET): immunotherapy (n = 3), tipifarnib (n = 1), NOTCHi (n = 1), EGFRi (n = 2), HER2i (n = 1) and everolimus (n = 11). Overall, 67% of patients had a clinical benefit defined as a GMI over 1.3 with a 78% disease control rate. CONCLUSION: We report 48% of NEN with a putative actionable MA of which 35% received molecularly matched treatment, with a clinical benefit in 67% of the cases.

Single-agent gemcitabine in patients with advanced, pre-treated angiosarcoma: A multicenter, retrospective study.

Gemcitabine has shown clinical activity against angiosarcoma in small series, alone, or combined with taxanes. We aimed to evaluate its activity as a single-agent in a larger series of patients with advanced angiosarcoma. We retrospectively reviewed the electronic medical records of consecutive adult patients with advanced angiosarcoma treated with single-agent gemcitabine at our institutions from January 2010 to January 2021. Response was evaluated according to RECIST 1.1, and toxicity was graded according to NCI-CTC v5.0. 42 patients were identified. 38 patients (90%) had received prior anthracyclines and weekly paclitaxel, and 9 (21%) had received pazopanib. The best tumor response was partial response (PR) in 16 patients (38%), or stable disease (10 patients, 24%). All 8 patients with cardiac angiosarcoma experienced a PR. Median PFS was 5.4 months (95%CI: 3.1-6.5), and median OS was 9.9 months (95%CI: 6.6-13.4). Single-agent gemcitabine has clinically meaningful activity in advanced, heavily pre-treated angiosarcoma.

A novel fusion variant LSM14A::NR4A3 in extraskeletal myxoid chondrosarcoma.

Extraskeletal myxoid chondrosarcoma (EMC) is a rare soft tissue neoplasm of uncertain lineage characterized by the pathognomonic rearrangement of the NR4A3 gene, which in most cases is fused with EWSR1. Other NR4A3 fusion partners have been described, namely TAF15, FUS, TCF12, and TGF. Some studies suggest that EMCs with non-EWSR1 variant fusion are associated with high-grade morphology and worst clinical behavior compared to EWSR1::NR4A3 tumors, supporting the potential significance of particular fusion variant in EMC. We report a case of a 34-year-old male who presented with calf EMC and subsequently developed a slowly progressive metastatic disease 3 years after diagnosis. Whole-transcriptome analysis with total RNA sequencing enabled identification of a novel fusion transcript LSM14A::NR4A3, expanding the molecular spectrum of EMC.

Second-line treatment and prognostic factors in neuroendocrine carcinoma: the RBNEC study.

Neuroendocrine carcinomas (NEC) are aggressive malignant diseases. Etoposide-based rechallenge (EBR) and the prognostic role of RB transcriptional corepressor 1 (RB1) status in second-line chemotherapy (2L) have not been studied. The objectives of this study were to report the results of 2L including EBR as well as prognostic factors in a national retrospective multicentre study. NEC patients treated with 2L and further, with tissue samples available, were included. RB1 status and morphological classification were reviewed centrally. Among the 121 NEC patients (40% female, median age 61 years) included, there were 73 small-cell NEC (60%), 34 large-cell NEC (28%) and 14 NEC (not otherwise specified, 12%). Primary sites were lung (39%), gastroenteropancreatic (36%), other (13%) and unknown (12%). Median Ki-67 index was 80%. Median progression-free survival (PFS) and overall survival (OS) under 2L were 2.1 and 6.2 months, respectively. No difference was observed between patients who received an 'adenocarcinoma-like' or a 'neuroendocrine-like' 2L or according to the RB1 status. Thoracic NEC primary was the only adverse prognostic factor for OS. EBR, administered to 31 patients, resulted in a 62% disease control rate with a median PFS and OS of 3.2 and 11.7 months, respectively. In the 94 patients with a relapse-free interval of ≥3 months after first-line platinum-etoposide chemotherapy, the median OS was 12 months in patients who received EBR as compared to 5.9 months in patients who did not (P = 0.043). EBR could be the best 2L option for patient with initial response to first-line platinum-etoposide lasting at least 3 months. RB1 status does not provide prognostic information in this setting.

Succinate: A Serum Biomarker of SDHB-Mutated Paragangliomas and Pheochromocytomas.

CONTEXT: Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors that are frequently associated with succinate dehydrogenase (SDH) germline mutations. When mutated, SDH losses its function, thus leading to succinate accumulation. OBJECTIVE: In this study, we evaluated serum succinate levels as a new metabolic biomarker in SDHx-related carriers. METHODS: Retrospective monocentric study of 88 PPGL patients (43 sporadic, 35 SDHB, 10 SDHA/C/D), 17 tumor-free familial asymptomatic carriers (13 SDHB, 4 SDHC/D), and 60 healthy controls. Clinical, biological, and imaging data were reviewed. Serum succinate levels (n = 280) were quantified by an ultra-performance liquid chromatography coupled to a tandem mass spectrometry method and correlated to SDHx mutational status, disease extension, and other biological biomarkers. RESULTS: Serum succinate levels > 7 µM allowed identification of tumor-free asymptomatic SDHB-mutated cases compared to a healthy control group (100% specificity; 85% sensitivity). At PPGL diagnosis, SDHB-mutated patients had a significantly increased median succinate level (14 µM) compared to sporadic patients (8 µM) (P < 0.01). Metastatic disease extension was correlated to serum succinate levels (r = 0.81). In the SDHB group, patients displaying highest tumor burdens showed significant increased succinate levels compared to the sporadic group (P < 0.0001). CONCLUSIONS: In this pilot study, we showed that serum succinate level is an oncometabolic biomarker that should be useful to identify SDHB-related carriers. Succinate levels are also a marker of metabolic tumor burden in patients with a metastatic PPGL and a potential marker of treatment response and follow-up.