Expression of XRCC 1 and ERCC 1 proteins in radioresistant and radiosensitive laryngeal cancer

Summary Radiotherapy is the principal modality used to treat early stage laryngeal cancer in the UK. Unfortunately treatment failures occur in up to 25% of patients. Subsequent salvage surgery is technically more difficult with the consequences of increased complication and failure rates. The ability to predict radioresistance would significantly improve the poor survival associated with this disease. The efficiency of DNA repair is one of the critical determinants of cell fate following radiotherapy. Using immunohistochemical techniques we examined the expression of DNA repair proteins XRCC 1 and ERCC 1 in 108 pre-treatment laryngeal biopsy samples. All tumours were treated with single modality radiotherapy with curative intent. The group comprised 54 radioresistant and 54 radiosensitive tumours matched for T stage and smoking history. ‘Normal’ expression of both XRCC 1 and ERCC 1 was significantly associated with radioresistant tumours (p<0.001), with an accuracy of 69% in predicting radiotherapy treatment failure and a low false positive rate of 12%. Patients with predicted radioresistant tumours could be offered conservative laryngeal surgery as a first line treatment instead of radiotherapy. This treatment option is widely used in the USA and is equally as effective as radiotherapy for early stage laryngeal tumours.