Has the cellular proliferation marker Ki67 any clinical relevance in squamous cell carcinoma of the head and neck?

Over the years many laboratory factors have been studied with a view to predicting the course of head and neck cancer. The lack of success prompted the application of various measures of cell kinetics to this topic. The present study includes 79 patients with a proven squamous cell carcinoma of the head and neck at various sites and having various treatments. Ki67 staining was carried out using the avidin-biotin complex method and counts recorded per 1000 tumour cells. The patients' mean age was 61 years and the 5 year survival was 54% (95% CI, 29-73%). The median Ki67 index was 278 representing the number of cells stained positively per 1000 tumour cells. The minimum staining was 82 and the maximum 808 with a lower quartile of 95 and an upper quartile of 452. The Ki67 index failed to correlate with any host or tumour factors. In addition, median Ki67 values were not significantly different between irradiated tissue and non-irradiated tissue, between sites nor between patients who did and did not later develop lymph-node metastases. Of particular relevance is that Ki67 value did not correlate with survival. Data was further analysed using Cox's proportional hazards model for survival. Ki67 had no significant effect on survival. It is concluded that Ki67 index is of no value in predicting the course of squamous cell carcinoma of the head and neck.