Clinical Colorectal Cancer March 2006 • 429 Introduction Colorectal cancer (CRC) is the third most common malignancy in Western countries. 1 In Spain, CRC is the second most deadly type of cancer in women after breast cancer and the third in men after lung and prostate cancer. The treatment of CRC has advanced significantly over the past decade, resulting in progressively better cure rates. The introduction of screening strategies, better surgical techniques, and more effective adjuvant treatments have increased the survival of patients with early CRC. Despite these efforts, one third of patients will present with stage IV disease, and another 20%-25% of patients treated with curative intention will develop disease progression after surgery. The standard of care for these patients remains systemic chemotherapy despite cure rates remaining low. 2-6 Over the past few years, the systemic treatment of patients with advanced-stage CRC has witnessed 2 major developments. First, newer more active chemotherapy agents have been introduced. These new agents include the platinum- Multicenter Phase II Study of Fixed Sequences of Capecitabine Combined with Oxaliplatin or Irinotecan in Patients with Previously Untreated Metastatic Colorectal Cancer Abstract Submitted: Jan 30, 2006; Revised: Mar 10, 2006; Accepted: Mar 10, 2006 Address for correspondence: Javier Cassinello, MD, Servicio de Oncología Médica, Hospital Universitario de Guadalajara, Av Donantes de Sangre s/n, 19002 Guadalajara, Spain Fax: 34-949-209-237; e-mail: jacaes@sescam.jccm.es 1 Hospital Universitario de Guadalajara 2 Hospital Rodríguez Chamorro, Zamora 3 Hospital Nuestra Señora de Alarcos, Ciudad Real 4 Hospital Santa Bárbara, Soria 5 Hospital Central de la Defensa 6 Hospital Nuestra Señora del Valle 7 Hospital Nuestra Señora del Prado, Talavera de la Reina 8 Hospital Nuestra Señora de Sonsoles, Ávila Spain Javier Cassinello, 1 Jose Valero Álvarez, 2 María José García López, 3 Eduardo Pujol, 4 Antonio Colmenarejo, 5 Fernando Segovia, 6 Fernando Marcos, 7 Elena Filipovich, 8 Alberto Arcediano, 1 Inés García Castro 1 Purpose: The purpose of this study was to evaluate the antitumor activity and toxicity of fixed sequences of capecitabine/oxaliplatin followed by capecitabine/irinotecan in patients with previously untreated metastatic colorectal cancer. Patients and Methods: Adult patients with histologically confirmed, previously untreated, nonresectable, locally advanced or metastatic colorectal adenocarcinoma were enrolled in the study. Patients were treated as follows: capecitabine (1000 mg/m 2 orally twice daily) on days 1-14 and oxaliplatin (130 mg/m 2 2-hour intravenous infusion) on day 1, followed by capecitabine (1000 mg/m 2 twice daily) on days 1-14 and irinotecan (240 mg/m 2 1.5-hour intravenous infusion) on day 1. Each combination was administered every 21 days during 4 consecutive cycles followed by the alternating sequence to a maximum of 16 cycles. Results: A total of 35 eligible patients have been included in this ongoing study. Response rate (complete responses plus partial responses) was 37.1%.With a median follow-up of 9.5 months, the median time to disease progression and overall survival were 7.4 months and 16.4 months, respectively.Treatment was well tolerated, with only 6% of the patients developing grade 3/4 neurotoxicity.However,the low number of patients treated beyond 4 cycles limits the interpretation of the data. Conclusion: The preliminary results from this ongoing study suggest the feasibility of this strategy, which resulted in promising antitumor activity with less neurotoxicity. Clinical Colorectal Cancer, Vol. 5, No. 6, 429-435, 2006 Key words: Chemotherapy, Hematologic toxicity, Neutropenia, Thrombocytopenia Electronic forwarding or copying is a violation of US and International Copyright Laws. Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by CIG Media Group, LP, ISSN #1533-0028, provided the appropriate fee is paid directly to Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923 USA 978-750-8400. Contribution Original