Ploidy in head and neck cancer: a review and meta-analysis

Abstract

Summary A review is presented of all the series reporting ploidy in squamous cell carcinoma of the head and neck. A total of 1984 patients have been reported in 26 different series: 37% of tumours were diploid, 54% aneuploid and 11 % polyploid. Thus 64% of tumours were non-diploid. The mean age of patients with diploid and aneuploid tumours was very similar (60.9 and 60.3 years respectively) but patients with polyploid tumours had a mean age of 54 years. Although men were 5% more likely than women to have a non-diploid tumour the difference was not significant. Data relating ploidy to performance status are not available. The incidence of non-diploid tumours did not vary between sites, nor with stage grouping, but non-diploid tumours increased in frequency with diminishing degree of differentiation and with the presence of lymph node metastases. There was no difference in ploidy pattern between the primary tumour and node metastases. In the entire series the survival was better for diploid tumours than for non-diploid tumours. Subgroup analysis showed this effect to be due to mouth cancers, whereas ploidy did not affect the outcome in laryngeal cancer. Also, recurrence was more likely in non-diploid tumours. Patients with end-stage cancer treated by chemotherapy had a better survival if their tumour was non-diploid. Ploidy did not influence response to radiotherapy. When a tumour recurred after radiotherapy it was more likely to be diploid than a previously treated tumour. Non-diploid tumours had a greater S-phase fraction and a greater growth fraction than diploid tumours.