5055 Background: ERCC1 expression has been shown to be a molecular marker of cisplatin resistance in many tumor sites. However, it has not been well studied in cervical cancer. Purpose: To determine the impact of tumoral ERCC1 expression in patients with locally advanced cervical cancer treated with radiotherapy (RT) or chemoradiotherapy (CRT), in a large multicenter cohort. Methods: 463 patients with locally advanced cervical cancer, treated with radical RT or CRT (cisplatin-based) from 3 major Canadian cancer centers (BCCA, Vancouver (n = 90); TBCC, Calgary (n = 225); PMH, Toronto (n = 148) between 1986-2004 were evaluated. 308 patients (66%) were in the CRT cohorts and 155 (33%) were in the RT cohorts. Pretreatment FFPE tumor specimens were retrieved, and tissue microarrays were constructed. Tumoral ERCC1 (FL297 antibody) protein expression was measured using AQUA technology, and nuclear/cytoplasmic (n/c) ratio was calculated for standardization. The association of clinical factors and ERCC1 status with PFS and OS was determined at 3 years. Results: The majority of patients had FIGO stage II disease (53%); median tumor size was 5 cm. Median patient age was 52 years. Median follow-up was 5 years. Overall survival was 70% for the CRT cohorts, and 63% for the RT alone cohort (p = 0.076); PFS was 58% for both treatment cohorts (p = 0.54). OS was associated with age (HR 1.02, p = 0.0005), tumor size (HR 1.2, p < 0.0001), pre-treatment hemoglobin (Hgb) status (HR 2.63, p < 0.0001), and chemotherapy (HR 0.54, p = 0.0003). In addition, ERCC1 status was associated with OS (HR 2.44 [1.08-5.52], p = 0.03) and PFS (HR 2.08 [1.00-4.33], p = 0.05) in the CRT cohorts. No significant association between ERCC1 status and outcome was seen in the RT alone cohort. In the CRT cohorts ERCC1 status was not significant when the model was adjusted for the clinical factors: for OS (HR 1.84 [0.78-4.33], p = 0.16); for PFS (HR 1.55 [0.71-3.39] p = 0.27). Conclusions: Tumor size and pretreatment Hgb status were significantly associated with OS and PFS in patients treated with RT or CRT. ERCC1 status appears to have prognostic impact on univariate analysis in patients treated in the CRT cohorts, but was not independently associated with outcome. No significant financial relationships to disclose.