E40 - Clinical Outcome of Patients With Stage IV Colorectal Cancer Receiving Combination Chemotherapy Without Surgery As Initial Treatment

Abstract

Background: At the time of diagnosis, 25% of patients (pts) with colorectal cancer (CRC) present synchronous unresectable metastases. The best therapeutic option for this pts is not yet defined: primary tumor resection (PTR) followed by chemotherapy or upfront chemotherapy without PTR? Methods: We conducted a prospective observation trial. Main study's objective was to describe the incidence of primary tumor–related complications in pts with stage IV CRC who received up-front oxaliplatin- or irinotecan-based combination chemotherapy with or without target therapies. Secondary objectives were: overall response rate (ORR- according to RECIST criteria), toxicity (CTCAE v4), progression free survival (PFS) and clinical benefit (defined as: increase in body weight and appetite, improvement of existing symptoms such as pain, bleeding, anorexia, asthenia). Results: From July 2013 to January 2015, 38 pts with median age of 65.8 years (range 44-83), were enrolled. Primary tumors were: right colon (cecum, ascending or transverse colon) in 26.3% of pts, left colon (descending or sigmoid) in 52.6% and rectum in 21.1%. The most common sites of metastasis were: liver (65.8%), retroperitoneal nodes (48.1%), lung (52.7%), peritoneum (21.1%), bone (21.1%) and brain (13.2%). Metastases involved one site or organ in 52.6% of pts, two sites in 26.3%, three sites in 13.2% and four sites in 7.9%. Of 38 pts, 97,4% never required surgical palliation of their primary tumor. One patients (2,6%) required medical therapy for primary tumor subobstruction. No bleeding or intestinal perforation were observed in the site of primary tumor. After 6 months, 94.7% of pts was evaluable for response: ORR was 25%, no complete response (CR), was observed, disease control rate (CR + partial response + stable disease) was 75% and progression was 25%; median PFS was 9.3 months (range 3-15). Grade 3/4 toxicities were as follows: neutropenia 19.2%; diarrhea 11.3%; nausea-vomiting 1.6%. Pain improved in 80% of pts, constipation in 60% of pts with less need for medical treatment (laxatives and enemas toileting), appetite improved in 64.8% of pts and an increase in body weight was observed in 48.3% of pts. Conclusions: These data showed that upfront chemotherapy, without routine prophylactic resection, could be an appropriate therapeutic option for pts with neither obstructed nor hemorrhaging primary colorectal tumors in the setting of metastatic disease.