Analysis of response pattern for patients with recurrent or metastatic colorectal cancer treated with Irinotecan, 5-FU, and low dose leucovorin (modified FOLFIRI) as 1st line chemotherapy

Abstract

13546 Background: Irinotecan in combination with 5-fluorouracil (5-FU) and high dose leucovorin (LV), known as FOLFIRI regimen, has shown activity in recurrent or metastatic colorectal cancer. We analyzed the response pattern of irinotecan, 5-FU and low dose LV (modified FOLFIRI) as a first line therapy for patients with relapsed or metastatic colorectal cancer. Methods: Between September 2002 and November 2005, 46 patients with histologically confirmed recurrent or metastatic colorectal cancer were enrolled. The chemotherapy schedule consisted of irinotecan 180 mg/m2 intravenous (i.v) on day 1, 5-FU 400 mg/m2 as i.v bolus with 600 mg/m2 as a 22hr continuous infusion on day 1 and 2, leucovorin 20 mg/m2 on day 1 and 2, repeated every two weeks.We investigated the pattern of response to chemotherapy according to clinical parameters. Results: The overall response rate was 47.8%. There was no difference according to disease status and location of primary cancer, but Each metastatic lesions showed different response to chemotherapy. The response rate for metastatic lesions in liver was 54.2%, but only 7.7% for lung lesion. Most peritoneal lesions and lymphadenopathies showed stable disease (60.0% and 55.6%, respectively). 27 patients received 2nd line chemotherapy with oxaliplatin, 5-FU and leucovorin (FOLFOX regimen) after progressive disease. The overall response rate with FOLFOX was 15.2%. With 2nd line chemotherapy, response rate for lesions in liver was 23.5%, but 11.1% for lung lesions. For peritoneal seeding, no response was observed (72.7% stable disease). If the lesion did not achieve response to 1st line chemotherapy, it did not showed response to 2nd line treatment. Conclusions: The response to chemotherapy may be different according to metastatic site within same cancer. The lesions in liver may respond better than those in lung. If the lesion is classified ‘refractory‘ with 1st line treatment, or stage IV cancer with lung or peritoneal seeding only, we may consider more aggressive treatment to achieve better response. No significant financial relationships to disclose.