The colon cancer recurrence test ColoPrint? (Agendia, Amsterdam, The Netherlands) significantly improves prognostic accuracy over assessment solely based on pathologic factors and microsatellite instability in patients with stage II and III colorectal cancer who are either at low risk or at high risk of experiencing a disease relapse. In combination with classical pathological criteria, ColoPrint facilitates the identification of stage II patients who may be safely managed without chemotherapy.

These are findings from investigators in Spain, the UK, and the Netherlands published in the online edition of the Journal of Clinical Oncology (November 22, 2010).

In combination with clinical parameters, ColoPrint can provide clinicians with a reliable means to assist them in adjuvant treatment decision-making.

The study aimed to develop a robust gene expression classifier that can predict disease relapse in patients with early-stage colorectal cancer (CRC). ColoPrint was developed using an unbiased analysis of the entire human genome to identify recurrence-related genes. Frozen tumor tissue from 188 untreated patients with stage I to IV CRC was analyzed using Agilent 44K oligonucleotide arrays. A nearest mean classifier was developed using a cross-validation procedure and an optimal set of 18 genes was identified. The signature was validated on an independent set of 206 samples from patients with stage I, II, and III CRC.

In the subset of patients with stage II disease, ColoPrint correctly identified most patients (63%) as low risk. Low risk patients had a chance of 90.9% to remain relapse free for 5 years while high risk patients had only a 73.9% 5-year relapse-free survival (RFS). In stage II patients, ColoPrint was the strongest predictor for RFS in the univariate analysis (HR, 3.34; 95% CI, 1.24 to 9.00; P 0.017) and multivariate analysis. The classifier performed independently from the ASCO risk criteria when analyzed either individually or combined (HR, 3.66; 95% CI, 1.24 to 9.08; P 0.017). Furthermore, in the analysis of all samples and of samples from patients with stage III disease only, ColoPrint remained a strong independent prognostic factor.

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The study’s lead author is Ramon Salazar, MD, from the Institut Catala` d’Oncologia-IDIBELL, L’Hospitalet de Llobregat, in Barcelona, Spain. The co-authors are from Agendia; the Netherlands Cancer Institute and Slotervaart Hospital in Amsterdam, the Netherlands; Leiden University Medical Center in Leiden, the Netherlands; and the University of Oxford, Radcliffe Infirmary, in Oxford, United Kingdom.

The results of a second independent validation study by principal investigators from the university hospital Klinikum rechts der Isar, in Munich, Germany, have been submitted to the upcoming Gastrointestinal Cancers Symposium organized by the American Society of Clinical Oncology (ASCO GI) from January 20-22, 2011, in San Francisco.

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