Sandra Rojo

INTRODUCTION: Imatinib is the standard first-line therapy for advanced gastrointestinal stromal tumor. (18)F-fluorodeoxyglucose PET computed tomography (FDG PET/CT) shows a faster response than computed tomography in nonpretreated patients. PATIENTS & METHODS: After disease progression on imatinib 400 mg, 16 patients were exposed to 800 mg. Tumor response was evaluated by FDG PET/CT on days 7 and 37. Primary objective was to correlate early metabolic response (EMR) with progression-free survival (PFS). RESULTS: EMR by FDG PET/CT scan was not predictive of PFS. Median PFS in these patients was 3 months. Overall survival was influenced by gastric primary site (p = 0.05). CONCLUSION: The assessment of EMR by FDG PET/CT in patients with advanced gastrointestinal stromal tumor exposed to imatinib 800 mg was not predictive of PFS or overall survival.

e14521 Background: Thestandard treatment for biliary tract cancer is gemcitabine plus platinum, but median progression-free survival (PFS) is only 5-8 months (m) (Valle et al, NEJM 2010). Gene expression or somatic mutations may influence the clinical phenotype, which will affect decisions on individualized treatment. Methods: We retrospectively analyzed tissue blocks from 54 advanced or metastatic cholangiocarcinoma, gallbladder or ampulllary cancer patients (p) treated with single-agent gemcitabine or gemcitabine plus carboplatin or cisplatin. Using RT-PCR, we analyzed the mRNA expression levels of oncogenes, tumor suppressors and DNA repair genes (BRCA1, RRM1, AEG-1, RAP80, SPINK1 and FBXW7) and correlated results with PFS, overall survival (OS) and response. In addition, FBXW7 hotspot mutations were assessed. Results: p characteristics: 72% females; median age, 60 (40-87). Only FBXW7 expression correlated with PFS and OS. When FBXW7 levels were dichotomized at the median value, PFS was 4.2 m for p with low levels vs 12.6 m for p with high levels (p=0.02). When FBXW7 expression was divided by terciles, PFS was 4.9 m for p in the lowest tercile, 7.6 for p in the intermediate tercile, and 26.9 m for p in the highest tercile (p=0.08). OS was 6.2 m for p in the lowest tercile, 8 m for p in the intermediate tercile, and not reached for p in the highest tercile. No other significant correlation was observed between expression levels of the other genes examined and PFS or OS. Only AEG-1 expression correlated with response (p=0.05). No FBXW7 hotspot mutations were detected. Conclusions: Although we did not find the FBXW7 hotspot mutations previously described in biliary tract cancer, FBXW7 mRNA expression significantly influenced PFS and OS. A separate cohort of p is being analyzed to validate the prognostic role of FBXW7.


 
 
 La radioquimioterapia neoadyuvante radiosensibilizante seguida de escisión total del mesorecto, es tratamiento estándar en cáncer de recto localmente avanzado (LARC). La radioterapia de intensidad modulada (IMRT) permite respetar dosis de tolerancia en órganos a riesgo. El objetivo de este estudio fue registrar toxicidad aguda y tardía, cuantificar respuesta patológica completa (pCR) y su efecto en supervivencia global (SG) en la serie y pacientes operados y no operados.
 Estudio retrospectivo en108 pacientes tratados entre 2016-2019 con IMRT- SIB (boost simultáneo integrado) 54 Gy (Equivalente 57Gy) en 20 fracciones.
 El seguimiento medio fue de 31 meses, en 108 pacientes toxicidad aguda: dolor abdominal 55 (51%); meteorismo 42 (38.8%); enteritis G1 54 (50%), G2 31 (28.7%) y G3 4 (3.7%); rectitis G1 56 (51.4%), G2 33 (30.3%) y G3 1 (0.9%); epidermitis G1 55 (51%) y G2 18 (16.5%); proctorragia 57 (52.7%); disuria 33 (30.5%) e incontinencia anal 13 (12%). Toxicidad tardía en 103/108: enteritis G1 23 (22.3%), G2=6 (5.8%); rectitis G1 28 (27.2%), G2 6 (5.8%); proctorragia 14 (13.6%), incontinencia anal 10 (9.7%), disuria 3 (2.9%). En 51/103 ausencia de toxicidad tardía. En 80/108 operados 45 (56.25%) pCR. No hubo diferencia significativa en SG pCR versus respuesta parcial. La SG fue mejor en pacientes operados
 
 
 IMRT levemente hipofraccionada permite reducir el tiempo total de tratamiento y aplicar dosis > 50Gy en el tumor, obteniendo tasa de respuesta parcial y completa alentadoras con aceptable toxicidad.
 
 

10081 Background: Imatinib is the standard first-line therapy for advanced GIST patients. 18 F- fluorodeoxyglucose positron emission tomography (FDG-PET/CT) shows a faster response than CT in nonpretreated patients. After disease progression on imatinib 400 mg, FDG-PET/CT scans were performed to evaluate early response to imatinib 800 mg. Methods: After disease progression on imatinib 400 mg, 16 patients had their dose escalated to 800 mg and tumor response was evaluated by FDG-PET/CT on days 7 and 37. Objective assessment was performed according to the recommendations of the European Organization for Research and Treatment of Cancer (EORTC) PET Study group. The primary objective was to correlate early metabolic response with progression-free survival (PFS). Secondly, metabolic assessment, Response Evaluation Criteria in Solid Tumors (RECIST) and Choi criteria were compared. Ninety-five lesions were assessed in 46 FDG-PET/CT. Results: Early metabolic assessment by FDG-PET/CT scan was not predictive of PFS in advanced GIST patients treated with imatinib 800 mg daily. Median PFS was 5.3 months. Gastric primary site and previous exposure to imatinib 400 mg for over 12 months were statistically significant positive predictive factors for PFS (p 0.02). Three partial responses were observed on day 7 FDG-PET/CT but time to progression was 2 months (range 2-3). No objective responses according to RECIST criteria were observed on Day 7 or 37. There was a trend towards an earlier identification of partial responses or disease progression with PET and Choi than RECIST. In this group of patients, OS was only influenced by gastric primary site (p 0.05). Metabolic response or other clinical-molecular variables did not impact in OS. Conclusions: The assessment of early metabolic response by FDG-PET/CT in advanced GIST patients exposed to imatinib 800 mg was not predictive of PFS or OS. No significant financial relationships to disclose.