645 - The prognostic significance of tymidine kinase activity levels in metastatic colorectal cancer

Date 28 September 2012
Event ESMO Congress 2012
Session Publication Only
Topics Colon Cancer
Rectal Cancer
Translational Research
Presenter Erdogan Seber
Authors E.S. Seber1, T. Korkmaz2, K. Okutur3, F. Dane4, P.F. Yumuk4, B. Aktas5, M. Kanıtez4, G. Demir3, S.N. Turhal1
  • 1Medical Oncology, Marmara University Hospital, TR-34600 - Istanbul/TR
  • 2Medical Oncology, Dr lutfi kirdar kartal research and educational hospital, 34600 - istanbul/TR
  • 3Medical Oncology Department, bilim university, 32156 - istanbul/TR
  • 4Medical Oncology Department, marmara university hospital, istanbul/TR
  • 5Marmara University Faculty of Medicine, Istanbul/TR

Abstract

Aim and background

Serum thymidine kinase 1 (TK1) is a sensitive marker of tumor cell proliferation. It has been reported as a predictive factor for response rate and disease free survival for hematological and early stage solid organ tumors but its importance as a prognostic factor in metastatic solid organ malignancies is not well studied. In this study we aimed to investigate the prognostic significance of serum TK1 activity in metastatic colorectal cancer (MCRC) patients receiving palliative chemotherapy.

Method

We prospectively measured serum TK1 activity immediately before the first and second cycle of the treatment in 46 consecutive metastatic MCRC patients. 10 healthy volunteers were also included as a control group. TK1 activity was measured by means of high sensitive non-radioactive DIVITUM assay. The patients' performance status, age, gender, weight loss, hematological and biochemical parameters, serum CEA and CA 19.9 levels and serum TK1 activity levels relation with survival were analyzed.

Results

The mean TK1 level in the study group was significantly higher than the controls (162.1± 27.8 vs 32.97 ± 7.307; p < 0.03, respectively). In multivariate analysis adjusted for known clinicopathological risk factors, serum tumor markers, hemoglobin levels and trombosit count TK1 levels before chemotherapy and weight loss remained as independent prognostic factors ( p = 0.001; 0.018, respectively). Patients with TK1 activity level above 65 Du/L and 230 Du/L had a longer PFS (624 vs. 231 days) and OS time respectively (p <0.0001 for each cut off value). Although the mean TK1 levels before second cycle of chemotherapy was higher than baseline TK1 levels significantly no significant relationship between the magnitude of difference and survival time was detected (p = 0.6).

Conclusion

In this study we demonstrated that in the setting of MCRC a significant relation between TK1 levels and survival exists. We consider our results a step further for validation of serum TK1 activity level as an independent prognostic factor in metastatic solid organ tumors.

Disclosure

All authors have declared no conflicts of interest.