Impact of Positive Resection Margins on Recurrence and Survival Following Resection and Adjuvant Chemotherapy in Pancreatic Cancer: Results of the PRODIGE 24-CCTG PA-6 Randomized Controlled Trial.

OBJECTIVE: This study investigated the correlation between positive resection margins and outcomes in patients with pancreatic ductal adenocarcinoma who underwent surgery and adjuvant chemotherapy according to the pivotal trial PRODIGE 24-CCTG PA-6. BACKGROUND: The primary focus is on elucidating the prognostic significance of specific resection margins, including those associated with the superior-mesenteric vein (SMV), medial, and posterior pancreas. METHODS: The analysis involved 400 patients across multiple centers in France and Canada. Surgical resection and subsequent adjuvant chemotherapy were core interventions. This study assessed the prognostic impact of resection margins, highlighting the significance of standardized pathology assessments. Additionally, the influence of chemotherapy regimen choice, comparing gemcitabine to mFOLFIRINOX, on the implications of positive resection margins was examined. RESULTS: Only three margins, SMV (HR=1.48 95% CI [1.11;1.96], P<.001), medial (HR=1.92 95% CI [1.36;2.73], P<.001) and posterior (HR=1.65 95% CI [1.21;2.24], P=.002), had a significant prognostic impact on disease-free survival and were sufficient compared with the seven recommended margins (Kappa=0.90 95% CI [0.87; 0.94]). R1 status was significant independent prognostic factor for poorer survival in gemcitabine-treasted patients (HR=1.97 95% CI [1.23;3.16], P=.005) but lost its significance with mFOLFIRINOX (HR=1.46 95% CI [0.91;2.35], P=.114). CONCLUSIONS: All efforts should be made to evaluate the three margins of the highest prognostic value, with the others being secondary. A key finding of this study is the likely effect of mFOLFIRINOX on local invasion in operated patients, which seems to correct the impairment related to margin involvement, probably explaining the improvements in DFS and OS.

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy to Treat Pseudomyxoma Peritonei of Ovarian Origin: A Retrospective French RENAPE Group Study.

BACKGROUND: Ovarian pseudomyxoma peritonei (OPMP) are rare, without well-defined therapeutic guidelines. We aimed to evaluate cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) to treat OPMP. METHODS: Patients from the French National Network for Rare Peritoneal Tumors (RENAPE) database with proven OPMP treated by CRS/HIPEC and with histologically normal appendix and digestive endoscopy were retrospectively included. Clinical and follow-up data were collected. Histopathological and immunohistochemical features were reviewed. RESULTS: Fifteen patients with a median age of 56 years were included. The median Peritoneal Cancer Index was 16. Following CRS, the completeness of cytoreduction (CC) score was CC-0 for 9/15 (60%) patients, CC-1 for 5/15 (33.3%) patients, and CC-2 for 1/15 (6.7%) patients. The median tumor size was 22.5 cm. After pathological review and immunohistochemical studies, tumors were classified as Group 1 (mucinous ovarian epithelial neoplasms) in 3/15 (20%) patients; Group 2 (mucinous neoplasm in ovarian teratoma) in 4/15 (26.7%) patients; Group 3 (mucinous neoplasm probably arising in ovarian teratoma) in 5/15 (33.3%) patients; and Group 4 (non-specific group) in 3/15 (20%) patients. Peritoneal lesions were OPMP pM1a/acellular, pM1b/grade 1 (hypocellular) and pM1b/grade 3 (signet-ring cells) in 13/15 (86.7%), 1/15 (6.7%) and 1/15 (6.7%) patients, respectively. Disease-free survival analysis showed a difference (p = 0.0463) between OPMP with teratoma/likely-teratoma origin (groups 2 and 3; 100% at 1, 5, and 10 years), and other groups (groups 1 and 4; 100%, 66.6%, and 50% at 1, 5, and 10 years, respectively). CONCLUSION: These results suggested that a primary therapeutic strategy using complete CRS/HIPEC for patients with OPMP led to favorable long-term outcomes.

Integrated Molecular Characterization of HER2-Low Breast Cancer Using Next Generation Sequencing (NGS).

Based on immunohistochemistry (IHC) and in situ hybridization (ISH), HER2-low breast cancers (BC) subtype-defined as IHC1+ or IHC2+/ISH- tumors-emerged and represent more than half of all BC. We evaluated the performance of NGS for integrated molecular characterization of HER2-low BC, including identification of actionable molecular targets, copy number variation (CNV), and microsatellite instability (MSI) analysis. Thirty-one BC specimens (11 HER2+, 10 HER2-, and 10 HER2-low) were routinely analyzed using IHC and ISH, and were selected and analyzed using NGS for gene mutations including ESR1, PIK3CA, AKT1, ERBB2, TP53, BRCA1, and BRCA2, CNV, and MSI. CNV values for the ERBB2 gene were significantly (p < 0.001) different between HER2+, and either HER2-low or HER2- tumors with mean values of 7.8 (SD = 6.8), 1.9 (SD = 0.3), and 2.0 (SD = 0.3), respectively. Using 3.25 as the cutoff value, 96.8% overall concordance of HER2 status was achieved between IHC and NGS compared to IHC and ISH. Using NGS, gene mutations and amplifications were detected in 68% (21/31) and 19% (6/31) of the cases, respectively. One case of MSI was detected in a HER2-negative and ISH unamplified case. Beside IHC, NGS allows the identification of HER2-low subtype simultaneously, with the detection of multiple actionable gene mutations being helpful for molecular board treatment selection.