Expression of ERCC1 protein (excision repair cross complementing group 1) in patients with invasive carcinoma of the uterine cervix (CC) undergoing definitive chemoradiation (CR)

Abstract

Background: CC is the leading cause of cancer death among women in developing countries. ERCC1 protein participates in DNA repair through the nucleotide excision repair pathway, involved in resistance to platinum-based chemotherapy. Its value as a predictive marker of tumor response to treatment, progression or death is still unknown. We evaluated ERCC1 protein expression and clinical variables as a predictive marker of progression-free survival (PFS) and overall survival (OS) in patients (pts) with CC submitted to CR. Methods: Retrospective data analysis of pts with histological diagnosis of CC, treated with CR between 2004-2009. Platinum-based chemotherapy was administered weekly (x6) concurrent to external beam radiotherapy (EBRT) to the pelvis (39.6 – 45.0 Gy), parametrial boost (14.0 – 20.0 Gy) when indicated and high-dose rate brachytherapy (HDR) (28.0 – 30.0 Gy). ERCC1 expression was assessed by immunohistochemistry (IHC). Results: We analyzed 75 pts, median age was 55 years (range 24-76), the performance status (PS) was 0 or 1 at baseline in 50 pts (66%) and 63 had squamous histology (84%). Thirty-two were stage IIB (43%) and 19 were IIIB (25%). Sixty-five patients received cisplatin 40mg/m2/w (87%) and 9, carboplatin AUC2/w (12%), median of 6 cycles (range 2-9). Median RT and HDR doses were 59.4 Gy (range 40.4 to 60.3) and 28.0 Gy (range 14.0 – 37.5), respectively. Thirty-two pts were available by ERCC1 IHC and all expressed the marker. Median PFS and OS were 35.5 (95% CI – 13.8 - 57.6) and 81 (95% CI- 21.2 - 140.8) months, respectively. In multivariate analysis, receiving < 6 chemotherapy cycles and baseline Hb <10.0 were correlated with disease progression and death, HR 0.302; p 0.011 (95% CI- 0.012-0.762) and HR 0.6; p 0.00 (95% CI- 0.474 – 0.760), respectively. PS at baseline did not correlate with PFS or OS, HR 0.985; p 0.614 (95% CI 0.930 – 1.044). Conclusions: In this population, since all pts expressed the protein, ERCC1 expression couldn't discriminate patients who most benefit from CR. Interestingly, a minimum of 6 chemotherapy cycles and a baseline Hb ≥ 10.0 seem to have a prognostic value.