P-340 Bidirectional chemotherapy for patients with gastrointestinal peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is a common manifestation in gastro-intestinal (GI) cancers with highest incidence gastric and colon cancer. Around 20 % of patients developp isolated, unresectable PC poor prognosis low sensitivity to systemic chemotherapy. In most the cases, disease progression results bowel obstruction malnutrition, making difficult pursuit therapy. We aimed describe prospective cohort cancer predominant peritoneal treated bidirectional (intraperitoneal systemic) chemotherapy our institution. The primary objective was feasibility intraperitoneal administration, control disease, defined as absence clinical and/or scannographic progression, overall survival. Between 2017-2022 total 29 pts received (BD) main characteristics were follow: 15 males (52%), median age 55 years (IQR: 32-74); colorectal (n=14, 48%) (n= 14, cancers.The majority had mucinous histology (n=25, 86%). BD approach decided by multidisciplinary tumor board 91% (n=27) baseline celioscopic exploration for index (PCI) assessment catheter (KT) placement. 2 (7%) KT placed interventional radiology. PCI 8-34). (IP)was performed first line(n=14,48%), second line :28%(n=8); further lines(n=6,21%) or adjuvant setting(n=1,3%). 59% (n=17) IP oxaliplatin while 41%(n=12) paclitaxel. All concomitant intravenous chemotherapy: mainly 5FU -irinotecan (n=10,35%) oxaliplatin(n=7,24%) based . number cycles 4 1-20); only one cycle BD, because obstruction. (69%, n=20) morphologic stable (assessed CT scan)disease best response but significant benefit(less abdominal pain ascites).Intermediate done 11 pts(38%). Five (n=17%) could access curative-intent surgery, two are still alive; (3%) free after follow-up 3 months duration 5.5 (IC 95% 5.24 - 11.29) all group better numeric 8.64 (95%CI 4.26-13.01) compared 5.47months (95% CI: 2.65- 8.29) ,p-0.18. OS 18.5 months(95%CI 18.00-26.85).The numerically higher cancer, without statistical difference (23 vs 22 months, p =0.5).62%(n=19) at least treatment administration. Tolerability: 41% (n=12) presented Oxaliplatin administration; 25% (n=3) grade 2, during 24 h administration.2 (n=7%) infection. Bidirectional seems feasible GI achieving interesting terms control.Gastric seem have longer chemotherpy probably this earlier patients.