Head and neck squamous cell carcinoma has a relatively good prognosis but treatment may be at the expense of function and quality of life. Various host and tumour parameters have been studied in an attempt to predict the course of the disease but without success. It has been hoped that laboratory based methods, particularly those based on molecular biology, may prove more useful. Cell kinetic parameters are studied in this paper.The present study includes 75 patients with a proven squamous cell carcinoma of the head and neck at various sites and undergoing various forms of treatment. The patient's mean age was 62 years and the median survival rate 45 months. Immunohistochemical techniques using Ki67 and PCNA were compared with flow cytometric analysis which included the BRDU labelling index, the duration of S phase, ploidy and potential doubling time.The median PCNA index was 560 and the Ki67 index 298. These indices varied between 980 and 150 for PCNA and 808 and 110 for Ki67. The BRDU labelling index measured by flow cytometry was 8.9 with a range from 25 to 1.6 and the duration of S phase was 14.8 hours. The PCNA index failed to correlate with any host or tumour factors and this failure was also seen in Ki67 indices and also in the flow cytometric parameters. There was a strong correlation between PCNA and Ki67 expression (p<0.0001). Neither PCNA nor Ki67 values were significantly different between irradiated and nonirradiated tissues nor in sites or in patients who later developed lymph node metastases. Neither PCNA nor any other cell kinetics parameter correlated with survival and multivariate analysis confirmed this lack of correlation.The PCNA labelling index like the Ki67 index and flow cytometric parameters does not appear to be of value in predicting the course of squamous cell carcinoma of the head and neck.

Three accidental cases of accidental ingestion of radiolucent upper partial dentures are presented. As impaction in the upper gastrointestinal tract has a serious morbidity and even mortality, we recommend that dental surgeons consider this possibility when designing a prosthesis to replace anterior teeth.

Summary The cell kinetics of 82 squamous cell carcinomas of the head and neck were studied by in vivo administration of the thymidine analogue, bromodeoxyuridine (BrdUrd). Ploidy, BrdUrd labelling index (LI), duration of S-phase (Ts), potential doubling time (Tpot) and S-phase (Steel, 1977;Meyer, 1982). Cell kinetic studies in man, until recently, have been limited to in vitro investigations because of the ethical constraints of administering radioactive DNA precursors to patients. Tritiated thymidine labelling of freshly excised tissue followed by autoradiography has been widely used (Gentili et al., 1981;Brandt & Olsson, 1987;Courdi et al., 1989;Meyer & Bauer, 1975). The development of flow cytometric methods for measuring DNA content, particularly in paraffin embedded archival material, has resulted in DNA ploidy and S-phase fraction analysis being performed for many tumour types (Cornelisse et al., 1987;Armitage, 1985;Feichter et al., 1987

Summary We measured tumour cellular DNA in 102 patients entered into two phase III trials of chemotherapy for end stage squamous carcinoma of the head and neck. The median survival of untreated patients with aneuploid tumours was 55 days compared with 224 days for patients treated with cisplatinum. This difference was highly significant. In contrast the median survival of untreated patients with diploid tumours was 74 days compared with 118 days for treated patients. Although this difference is statistically significant, the increased survival of 6 weeks is of no clinical benefit compared with the prolongation of survival of 6 months in patients with aneuploid tumours. Multivariate analysis showed that the significant predictors of survival were Karnofsky status, response to chemotherapy and ploidy.

Summary Tumour growth rates were measured in 105 patients using in vivo incorporation of bromodeoxyuridine (BrdU) and investigated for any relationship to tumour factors or survival. The median labelling index (LI) was 8.7%, the duration of S-phase (Ts) was 14 h and the potential doubling time (Tpo) was 5.9 days. The labelling index in aneuploid tumours was significantly higher than that in diploid tumours. However the total labelling index (TLI) did not differ significantly between aneuploid and diploid tumours, and so it would seem likely that the difference in LI is due to the dilutional effect of benign tissue upon the calculation of LI in diploid tumours. The total labelling index, duration of S-phase and potential doubling time were not related to the tumour factors examined (site, T The general approach to measuring cell kinetics is to identify a 'window' in the cell cycle and measure the movement of a particular cohort of cells through this window. BrdU, an analogue of thymidine, is incorporated into cells during the S-phase of the cell cycle. BrdU is non-toxic and non-radioactive and can be given intravenously to human patients. Infusions of BrdU at higher dosage can be tolerated for several weeks without severe myelosuppression (Mitchell et al., 1983;Kinsella et al., 1984) and there have been no reports of toxic reactions in any patients receiving BrdU at 200 mg m2. It is taken up by the tumour, and the proportion of cells that have taken up BrdU can be detected using monoclonal antibodies. Furthermore, a pulse label of BrdU can be given approximately 6 h before biopsy or excision of the tumour, allowing the length of S-phase to be calculated (Begg et al., 1985). The simultaneous measurement of BrdU and DNA content using flow cytometry enables several cell kinetic parameters to be quantified. We have previously reported upon the cell kinetic results in 82 tumours and demonstrated their reproducibility (Forster et al., 1992).In this study we present further cell kinetic data on 105 patients with squamous cell tumours of the head and neck and investigate the relationship to tumour stage, site and prognosis.