Prospective evaluation of cell kinetics in head and neck squamous carcinoma: the relationship to tumour factors and survival

Where Do We Look for Markers of Radiotherapy Fraction Size Sensitivity?

The response of human normal tissues to radiotherapy fraction size is often described in terms of cellular recovery, but the causal links between cellular and tissue responses to ionising radiation are not necessarily straightforward. This article reviews the evidence for a cellular basis to clinical fractionation sensitivity in normal tissues and discusses the significance of a long-established inverse association between fractionation sensitivity and proliferative indices. Molecular mechanisms of fractionation sensitivity involving DNA damage repair and cell cycle control are proposed that will probably require modification before being applicable to human cancer. The article concludes by discussing the kind of correlative research needed to test for and validate predictive biomarkers of tumour fractionation sensitivity.

Biomarkers of head and neck cancer, tools or a gordian knot?

Head and neck tumors comprise a wide spectrum of heterogeneous neoplasms for which biomarkers are needed to aid in earlier diagnosis, risk assessment and therapy response. Personalized medicine based on predictive markers linked to drug response, it is hoped, will lead to improvements in outcomes and avoidance of unnecessary treatment in carcinoma of the head and neck. Because of the heterogeneity of head and neck tumors, the integration of multiple selected markers in association with the histopathologic features is advocated for risk assessment. Validation of each biomarker in the context of clinical trials will be required before a specific marker can be incorporated into daily practice. Furthermore, we will give evidence that some proteins implicated in cell-cell interaction, such as CD44 may be involved in the multiple mechanism of the development and progression of laryngeal lesions and may help to predict the risk of transformation of the benign or precancerous lesions to cancer.

Nomogram for deciding adjuvant treatment after surgery for oral cavity squamous cell carcinoma

BACKGROUND

The application of appropriate adjuvant treatment after surgery for oral cavity squamous cell carcinoma (OCSCC) is predicated on accurate patient risk stratification.

METHODS

A nomogram for estimating locoregional recurrence-free survival (LRFS) after treatment of OCSCC was constructed from a cohort of 590 patients with OCSCC who were treated at Memorial Sloan-Kettering Cancer Center (MSKCC). The nomogram was validated using a series of 417 patients with OCSCC who were treated at Hospital do Cancer AC Camargo (HACC) in São Paulo, Brazil.

RESULTS

Despite significant differences between the MSKCC and HACC cohorts, the nomogram was able to predict LRFS from OCSCC with a concordance index of 0.693. Further statistical analysis showed that the nomogram was well calibrated.

CONCLUSIONS

This preliminary nomogram is the first prognostic model developed and externally validated to predict the likelihood of LRFS after treatment for an individual patient with OCSCC and may have practical utility for deciding adjuvant treatment.

DNA ploidy, proliferative capacity and intratumoral heterogeneity in primary and recurrent head and neck squamous cell carcinomas (HNSCC) – Potential implications for clinical management and treatment decisions

Despite new diagnostic and therapeutic strategies (combined radiochemotherapy, EGFR antibody Cetuximab), the prognosis of head and neck squamous cell carcinoma (HNSCC) is still poor and more information regarding prognosis is essential to establish earlier and better treatment options. To elucidate the role of DNA ploidy and cellular proliferation, resected tumors of 48 patients with primary or recurrent HNSCC were analyzed by flow cytometry and in vitro-5-bromodeoxyuridine incorporation (BrdU). The results were compared with histopathological findings such as tumor size, lymph node involvement and tumor differentiation. To assess the influence of intratumoral heterogeneity of these biological parameters, multiple biopsies (>3) were analyzed by flow cytometry and BrdU-incorporation in 12 larger (>4 cm diameter) tumors. BrdU-labeling index (LI%) was significantly higher in aneuploid HNSCC and correlated significantly with poor histologic differentiation of the analyzed tumor tissues (P<0.001). Furthermore, a trend for higher LI% in nodal positive tumors was observed. Aneuploid HNSCC showed significantly more often tissue dedifferentiation (P=0.049) and in most cases an advanced tumor stage, especially in tumors with biclonal cell lines. Lymph node involvement was also seen more often in aneuploid and undifferentiated tumors. As in aneuploid tumors recurrent HNSCC showed in most cases a higher LI% and poor tissue differentiation, but as a result of the small collection of samples there was no correlation between aneuploidy and tumor recurrence. To proof the robustness of the acquired data and to estimate the influence of intratumoral heterogeneity to ploidy and LI% multiple biopsies were analyzed in larger tumors. Using a specific statistical algorithm a secure estimation of ploidy and LI% was possible by a single biopsy in these tumors. These findings indicate aneuploidy and proliferative activity as important findings for malignant progression in HNSCC. An estimation of these biological parameters may be useful for identification of patients with high risk for lymph node involvement or tumor recurrence and pre-treatment can be performed by a single biopsy. As a conclusion, these patients may benefit from more aggressive treatment.

Evaluation of metastatic lymph nodes in head and neck cancer: a comparative study between palpation, ultrasonography, ultrasound-guided fine needle aspiration cytology and computed tomography

STUDY DESIGN

In head and neck cancer patients, diagnosis of metastatic lymph nodes of the neck is essential for treatment planning and prognosis assessment. In a retrospective study, we compared palpation, ultrasonography, ultrasound-guided fine needle aspiration and computed tomography in patients with head and neck cancer.

METHODS

Results of palpation, ultrasonography and computed tomography were available in 78 out of 110 patients diagnosed with head and neck cancer. Ultrasound-guided fine needle aspiration cytology was performed in 26 of these patients. Patients with suspected lymph node(s) observed in one or more techniques underwent neck dissection.

RESULTS

Twenty seven patients underwent neck dissection, studying 150 lymph node regions. The sensitivity, specificity, positive predictive value, negative predictive value and efficacy were calculated for palpation (48.7%, 95.5%, 79.2%, 84.1%, 83.3% respectively), ultrasonography (65.8%, 83.0%, 56.8%, 87.7%, 78.7% respectively), ultrasound-guided fine needle aspiration cytology (86.7%, 87.5%, 81.3%, 91.3%, 87.2% respectively) and computed tomography (52.5%, 83.6%, 53.9%, 82.9%, 75.3% respectively).

CONCLUSIONS

In the assessment of lymph node metastases of the neck in patients with primary head and neck cancer, we found a high specificity for palpation of the neck and an acceptable efficacy for both ultrasonography and computed tomography being comparable between the two methods. Efficacy of ultrasound-guided fine needle aspiration cytology was high approaching the value of 90%.

Prognostic relevance of cell proliferation in head and neck tumors

Cell proliferative activity has been extensively investigated in head and neck tumors. Ki67/MIB-1 immunostaining, tritiated thymidine or bromodeoxyuridine labeling indices, DNA S-phase fraction, proliferating cell nuclear antigen expression, potential doubling time and analysis of the nucleolar organizer region associated proteins (AgNORs) have shown significant correlation with prognosis in 4806 cases of tumors of the oral cavity, salivary glands, pharynx and larynx. However, this was not observed in 2968 other reported cases. Discrepancies may depend on various factors: the heterogeneity of the series, which include tumors from various anatomic sites and patients treated with different therapy, and the lack of standardization of methods for assessing cell proliferation. Furthermore, none of the methods currently applied can by themselves define the actual proliferative activity, as it depends both on the proportion of cells committed to the cycle (growth fraction) and the speed of the cell cycle. Indeed, the actual proliferative activity of a tumor could well be measured by the equation [PA = Ki67 or MIB-1 scores x AgNORs], as we did in pharyngeal carcinoma. Provided that large and homogeneous series are evaluated by standardized methods, cell proliferative activity can still be regarded as an inexpensive and reliable prognostic factor in head and neck tumors.

Proliferative capacity in head and neck cancer

BACKGROUND

Shortening of overall treatment time (accelerated radiotherapy) appears to result in an increase of the efficacy of irradiation. In this study, we compared the proliferative capacity between tumors originating in different sites of the head and neck region. Tumors with a large proliferating capacity might, theoretically, benefit most from accelerated radiotherapy.

MATERIAL AND METHODS

BrdUrd was administered intravenously in patients with head and neck carcinomas. Tumor samples were analyzed with flow cytometry. T and N stages were assessed in accordance with the TNM classification system (UICC 1987).

RESULTS

No significant differences in proliferation parameters were observed with respect to site of origin of head and neck tumors. For T3/T4 tumors, DNA ploidy is an important tumor characteristic: G1- and S-phase fractions, labeling index, and tumor doubling time Tpot differences were statistically significant; the aneuploid tumors showed the largest proliferative potential.

CONCLUSIONS

(1) In general, no significant differences in proliferation parameters were observed with respect to site of origin. (2) Aneuploid head and neck tumors have a higher proliferative capacity than diploid ones, they might benefit most from accelerated irradiation.

Cell production rates in human tissues and tumours and their significance. Part II: clinical data

This paper reviews the available data for cell production rates of human tissues and tumours, measured in vivo using halogenated pyrimidine labelling and laser cytometry. The technique has now been widely evaluated, and we draw general inferences from the proliferative data over a broad range of tumour and tissue types. Estimates of the S-phase duration, the time taken for DNA synthesis in cycling cells, are consistent over a narrow range with a median value of around 10 hours, notwithstanding the constraints of the experimental and statistical technique, in normal tissues and tumours. This suggests that Ts values may be a species-specific constant. The more easily measured labelled S-phase fraction, or labelling index, shows much greater intra and intertumour variation within any one tumour class. It may thus be a surrogate for time dependent measurements to a first order approximation. The cell production rate, described by the potential doubling time (Tpot), is remarkably rapid in most tumours, a median value of the order of 5 days, and much faster than clinical volume doubling times for most lesions. The rapid cell production rates in normal tissues and tumours highlight the importance of cell loss in the growth and modelling of biological structures. Cell production rate measurements do not adequately describe the biological aggressiveness of tumours. They may be used to refine adjuvant strategies for radiotherapy and chemotherapy in experimental research. Dynamic halogenated pyrimidine labelling has provided unique and valuable insights into the living biology of human tissues and tumours.

Molecular markers as prognostic factors for local recurrence and radioresistance in head and neck squamous cell carcinoma

Squamous cell carcinoma of the head and neck affects more than 500,000 people worldwide each year. Local-regional recurrence of disease is a common and challenging oncological problem in patients affected by this disease. Identification of risk factors for local relapse after appropriate local therapy with surgery, radiation, or combination therapy remains an active area of clinical research. The recent development of novel molecular markers has resulted in numerous studies evaluating the prognostic significance and potential clinical utility of these markers in identifying patients at risk for local-regional relapse. This article reviews recent studies evaluating molecular markers, including p53, angiogenesis-related markers, cyclin D1, epidermal growth factor receptor, loss of heterozygosity, DNA ploidy, and cell kinetic markers. The potential clinical utility of these markers and future directions along this avenue of investigation are discussed.

The effect of heterogeneity in tumor cell kinetics on radiation dose-response. An exploratory investigation of a plateau effect

PURPOSE

To investigate the effect of heterogeneity in tumor cell kinetics on radiation dose-response curves for a population of patients.

MATERIALS AND METHODS

A series of exploratory calculations have been performed using an improved geometric-stochastic model of tumor cure.

RESULTS

Radiation therapy dose-response curves may plateau, or nearly so, at tumor control levels well below 100%, if a proportion of tumors would grow sufficiently fast to counterbalance the effect of fractionated radiotherapy. If the model assumptions of doubling time heterogeneity are correct, the difference between a short and protracted radiation regimen would be not only in the position and steepness of the radiation dose-response curve, but also in the level of the predicted plateau.

CONCLUSIONS

For a given rate of dose accumulation, the one-sided flattening in dose-response curves at high doses is predicted from the modeling, and determined by the proportion of most radioresistant and rapidly growing tumors. This shows that empirical models of tumor control probability which assume a symmetric sigmoid relationship from 0 to 100% have apparent limitations, seemingly not well acknowledged in the literature.

Potential tumour doubling time: determination of Tpot for various canine and feline tumours

Spontaneous tumours in dogs and cats are an excellent model for clinical human research, such as in developing proton conformation radiotherapy for humans. The kinetics of tumour cells can be used effectively to predict prognosis and response to therapy in patients with tumours. Knowledge of the kinetic parameters in these tumours is therefore important. In the present study the kinetic parameters evaluated included the labelling index (LI), relative movement (RM), mitotic index (MI), and potential doubling time (Tpot). These parameters were determined using in vivo labelling with bromodeoxyuridine, flow cytometry and histological preparation. Samples were obtained and evaluated from 72 dogs and 20 cats, presenting as patients in our clinic. Within the groups of epithelial and mesenchymal tumours from dogs and cats, the kinetic parameters LI, RM and MI were compared with Tpot. Significant correlations were observed for the comparison Tpot and LI. No correlation was found between Tpot and RM.

[Predictive tests of response to radiotherapy. Assessment and perspectives in 1997]

The potential tailoring of radiotherapy modalities to the biological characteristics of individual tumours and normal tissues appears to be an exciting way to improve the therapeutic, ratio in radiation therapy patients. Numerous assays have been proposed to provide the clinician with the biological information necessary to predict the outcome after irradiation and to guide the treatment prescription, but none of them has made its way to daily practice. Major difficulties are due to the technical burden of the procedures, the poor characterization of the assayed cells, and, moreover, the high complexity of tumour and normal tissues biology. The present paper reviews the present status of the assessment of tumour cells radiosensitivity, proliferation and oxygenation. Research remains extremely active in the field of biological predictors of response to irradiation. Future steps forwards are expected from progress in the available technologies, (re-)discovery of apoptosis and investigation of normal tissue tolerance.

Histological effects and predictive biomarkers of TPP induction chemotherapy for oral carcinoma

The effects of an induction chemotherapy with THP-adriamycin, cisplatin, and peplomycin (TPP) were studied in 32 patients with operable oral cancer. The histological evaluation according to the Shimozato-Oboshi classification was Grade (G) IV in ten cases (31.3%), GIII in one case, and GIIb in four cases. Induction of apoptosis and differentiation-inducing effects, hyperkeratinization or bone formation, were observed in some cases. The overall clinical response rate and histological response rate were 63% and 47%, respectively. Grade III was obtained in seven metastatic lymph nodes of three patients. The expressions of PCNA, p53, and AgNORs before and after chemotherapy were studied. The prechemotherapeutic PCNA positive cell index (PI) of the highly responsive tumors (GIII, IV) was significantly lower than that of the poorly responsive tumors (G0-IIb) (P < 0.01). Similar results were obtained in the evaluation of p53 PI (P < 0.05), suggesting that PCNA and p53 are useful biomarkers for predicting the efficacy of TPP chemotherapy.

Interrelationships of DNA-ploidy and cell proliferation markers with T-stage and N-stage in primary laryngeal tumors

PURPOSE

The purpose of this study was to evaluate the interrelationships of DNA-ploidy and cell proliferation markers with T-stage and N-stage in primary laryngeal tumors.

METHODS AND MATERIALS

DNA-index, S-phase fraction (SPF), 5-bromo-2'-deoxy-uridine (BrdUrd)-labeling index (LI), duration of S-phase (Ts), and potential doubling time (Tpot) were determined by flow cytometry. T-stage and N-stage were assessed in accordance with the TNM classification system (UICC 1987).

RESULTS

T1-2-, when compared with T3-4-stage tumors, had significantly higher LI values (independent from N-stage) resulting in lower Tpot values. No such relationship was found with respect to N-stage. N1-3 tumors, as opposed to NO tumors, appeared to be characterized by a significantly shorter Ts (and, hence, a shorter Tpot). Ts values appeared to vary considerably (range 1.9-6.2 h). For DNA-aneuploidy, as opposed to DNA-diploidy, a significantly higher geometric mean LI was noted. Locally advanced (T3-4) tumors, when compared with T1-2 tumors, were characterized by a significantly higher percentage of DNA-aneuploidy.

CONCLUSIONS

The reported lack of prognostic relevance of cell proliferation markers to predict radiation treatment efficacy may relate to a decreased proliferative capacity (LI, Tpot) in locally advanced (T3-4) tumors, as found in our series. In laryngeal tumors, the predictive value of cell proliferation markers (LI, Tpot) should, therefore, be evaluated after stratification for T-stage. The existence of higher LI values in DNA-aneuploidy tumors was confirmed in our series, stressing the need for distinction of DNA-diploid tumor cells from DNA-diploid normal cells. The prognostic potential of DNA-index was confirmed.

Treatment duration as a prognostic factor for local control and survival in epidermoid carcinomas of the tonsillar region treated by combined external beam irradiation and brachytherapy

PURPOSE

We wanted to study the influence of the time factor in a combination of external irradiation and brachytherapy from a retrospective study of 370 squamous cell carcinomas of soft palate and tonsil.

PATIENTS AND METHODS

From 1977 to 1993, 370 soft palate and tonsillar carcinomas were treated at the Centre Alexis Vautrin. All patients received external irradiation (ERT) with a minimum dose to the tumour of 45 Gy, followed by low dose rate brachytherapy by Iridium 192 using the technique of plastic tubes; 22 patients received neo-adjuvant chemotherapy. We treated 85 T1, 159 T2, 117 T3 and nine T4 or TX carcinomas; 128 of these had palpable nodes. There were 267 men and 24 women. The median age was 55 years (range 33-81 years).

RESULTS

The median duration of the total treatment was 57 days. The rate of local control was 88% at 5 years when the treatment time was 7 weeks and 74% when it was 9 weeks (P = 0.001). The rates of overall survival at 5 years were 63 and 44%, respectively (P < 0.0001). For the interval between external irradiation and brachytherapy the series was divided into three groups, i.e. patients treated with a delay inferior or equal to 16 days (2 weeks), patients for which the interval was between 16 and 20 days and patients treated with a delay greater than 20 days (3 weeks). The rates of local control and overall survival at 5 years were not significantly different in the two first groups so we amalgamated these two groups and compared them with the third group. In this way the time cut-off for the delay between external irradiation and brachytherapy was 20 days. At 5 years, the rate of local control was 85% for the group for which the interval was inferior to 3 weeks and 73% when the delay was greater (P = 0.01). The rates of overall survival at 5 years were 59 and 38%, respectively (P < 0.001). Multivariate analysis confirmed that protraction of treatment was a factor for poorer local control. This factor was independent of the other prognostic factors.

CONCLUSION

The total duration of irradiation and the delay between external irradiation and brachytherapy were significant prognostic factors for local control and overall survival of soft palate and tonsil carcinomas. The overall duration should not be greater than 7 weeks (external irradiation, 5 weeks plus a delay of 12-15 days between ERT and brachytherapy). The delay should never be greater than 20 days, but a boost should be considered to make up for the loss of local control.

Biological indicators of survival in patients treated by surgery for squamous cell carcinoma of the oral cavity and oropharynx

Squamous cell carcinomas of the head and neck are a heterogeneous group of tumours with regard to anatomical site, natural history and response to various treatments. Assessment of the role of biomarkers as indicators of prognosis or response to treatment is thus complex. In the last decade, different biomarkers have been investigated in the search for objective and reproducible indicators of prognosis. In 69 squamous cell carcinomas of the oral cavity or oropharynx from patients treated with radical surgery alone, we determined cell kinetics, evaluated as in vitro 3H-thymidine labelling index (TLI), p53, bcl-2 and glutathione S-transferase pi (GST pi) expression, by using immunohistochemical methods. The biological variables were unrelated to one another or to established clinical and pathological prognostic factors. Univariate analysis showed that a low proliferative activity was associated to a significantly higher risk of death than that observed in patients with a high TLI, whereas p53, bcl-2 and GST pi expression did not provide prognostic information. Multivariate analysis showed that cell proliferation, gender and nodal status retained their clinical relevance. In the subset of node-negative patients, TLI and p53 expression were indicators of survival. Moreover, the combined analysis of TLI and p53 expression identified a subgroup of node-negative patients with slowly proliferating and highly p53-expressing tumours who died within 1 year of radical surgery. These results indicate that in patients with operable oral cavity and oropharyngeal cancer, biomarkers can provide important information on clinical outcome.

Do cell kinetics have prognostic and/or predictive value in oesophageal cancer treated by surgery?

Tumour cell kinetics could help in predicting the optimal duration of treatment for the individual patient. In order to assess the importance of cell kinetics in oesophageal cancer, 63 patients with cancer of the oesophagus and/or gastro-oesophageal junction were studied. Seven patients had T1 tumours, six T2, 47 T3, and three T4. Twenty patients had no pathological nodes, while 43 patients had node-positive disease. Thirty-one patients had squamous cell carcinoma, 31 patients suffered from adenocarcinoma and one patient had signet ring cell carcinoma. The primary treatment was surgery. 5-iodo-2'-deoxyuridine (IUdR) was injected 6 to 10 h before surgery, and five biopsies per tumour were taken. The labelling index (LI), S-phase duration (Ts) and potential doubling time (Tpot) on the 305 biopsies taken were measured using flow cytometry. Overall, 1-year disease-free survival (DFS) was 57%, with the 2-year DFS being 38%. T-stage, pathological node status and sex significantly influenced the DFS. The mean Tpot from our 63 patients was 5.6 days, with a standard deviation of 3.6 days. When DFS was studied as a function of Tpot, no statistically significant difference was found between fast- and slow-proliferating tumours (log-rank, P = 0.84). A trend developed with fast-proliferating tumours recurring earlier than slow-proliferating ones. From our results it was also clear that intratumour variability exists, and is a confounding factor using Tpot as a predictor for treatment outcome. When tumours were classified into two categories, 'fast' or 'slow', according to their mean Tpot value (with the median Tpot (4.6 days) as the cut-off value), the trend for fast tumours recurring earlier was less clear than when the classification of tumours was based on the confidence interval (CI) being situated entirely below or above the mean. This classification into 'fast' or 'slow' included 27 of 63 tumours. The other tumours (n = 36) had a CI which included the cut-off, and could thus not be classified in this way. DFS at 1 year was 55% for the fast-proliferating tumours (n = 32) vs 63% for the slow-proliferating ones (n = 31). DFS at 1 year on the basis of the CI, however, was 38% for the fast-proliferating tumours (n = 17) vs 45% for the slow-proliferating ones (n = 10). Tumour cell kinetics have the greatest chance of predicting outcome in relatively long treatment schedules, where proliferation will have more time to occur. The fact that oesophageal tumours are almost all fast-proliferating tumours means that for new treatment schedules overall treatment time should not be unduly prolonged, whichever combination of surgery, radiotherapy and chemotherapy is used.

Enrichment of tumor cells for cell kinetic analysis in human tumor biopsies using cytokeratin gating

PURPOSE

To determine the feasibility of using cytokeratin antibodies to distinguish normal and malignant cells in human tumors using flow cytometry. The goal was ultimately to increase the accuracy of cell kinetic measurements on human tumor biopsies.

MATERIAL AND METHODS

A panel of four antibodies was screened on a series of 48 tumors from two centres; 22 head and neck tumors (Amsterdam) and 26 esophagus carcinomas (Leuven). First, screening was carried out by immunohistochemistry on frozen sections to test intensity of staining and the fraction of cytokeratin-positive tumor cells. The antibody showing the most positive staining was then used for flow cytometry on the same tumor.

RESULTS

The two broadest spectrum antibodies (AE1/AE3, E3/C4) showed overall the best results with immunohistochemical staining, being positive in over 95% of tumors. Good cell suspensions for DNA flow cytometry could be made from frozen material by a mechanical method, whereas enzymatic methods with trypsin or collagenase were judged failures in almost all cases. From fresh material, both collagenase and trypsin produced good suspensions for flow cytometry, although the fraction of tumor cells, judged by proportion aneuploid cells, was markedly higher for trypsin. Using the best cytokeratin antibody for each tumor, two parameter flow cytometry was done (cytokeratin versus DNA content). Enrichment of tumor cells was then tested by measuring the fraction of aneuploid cells (the presumed malignant population) of cytokeratin-positive cells versus all cells. An enrichment factor ranging between 0 (no enrichment) and 1 (perfect enrichment, tumor cells only) was then calculated. The average enrichment was 0.60 for head and neck tumors and 0.59 for esophagus tumors.

CONCLUSIONS

We conclude that this method can substantially enrich the proportion of tumor cells in biopsies from carcinomas. Application of this method could significantly enhance accuracy of tumor cell kinetic measurements.

Potential doubling time and clinical outcome in head and neck squamous cell carcinoma treated with 70 GY in 7 weeks

PURPOSE

To study the predictive value of pretreatment potential doubling time and labeling index, as measured by flow cytometry in patients with head and neck squamous cell carcinoma treated with conventional radiotherapy.

METHODS AND MATERIALS

70 patients with a squamous cell carcinoma of the oropharynx and 4 patients with another involved head and neck site were entered in this prospective study. The duration of the S phase (TS), the labeling index (LI), and the potential doubling time (Tpot) were obtained by flow cytometry measurements of a tumor biopsy obtained after i.v. injection of 200 mg bromodeoxyuridine to the patient. The treatment consisted of 70 Gy in 7 weeks, 2 Gy per fraction and five fractions per week.

RESULTS

The mean and median LI were 7.7% (standard deviation, SD: 5.0) and 6.3%, respectively. The mean and median TS were 9.3 h (SD: 3.6) and 8.3 h, respectively. The mean and median Tpot were 5.6 days (SD: 5.4) and 4.6 days, respectively. No significant relationship was found between the Tpot or LI and the tumor stage (T), nodal status (N), histological grade, and the site of the primary within the oropharynx. The only parameter significantly associated with an increased risk of local relapse was the tumor stage (p < 0.001). The mean Tpot for the group of tumors that relapsed locally was 5.3 days (SD: 3.3), compared to 6.1 days (SD: 4.08) for those who did not relapse locally (NS). Two parameters were significantly associated with a decrease in disease-free (DFS) and overall survival, namely the tumor stage (p < 0.005, and p < 0.001, respectively, for DFS and overall survival) and nodal involvement (p = 0.02 and (p < 0.005, respectively, for DFS and overall survival). The TS, LI, DNA index, and Tpot were not significantly associated with local relapse, DFS, and survival, either in the univariate or in the multivariate analysis.

CONCLUSIONS

The method used to evaluate tumor cell kinetics did not provide clinically relevant kinetic parameters for this type of cancer. The classic prognostic factors (tumor stage and nodal status) were strongly associated with clinical outcome.

Prognostic value of clinicopathological parameters in head and neck squamous cell carcinoma: a prospective analysis

The prognostic weight of histological and biological factors was compared with that of known clinical prognostic factors in a population of 108 consecutive previously untreated patients with head and neck squamous cell carcinoma. Parameters studied were: tumour vascularisation, mitotic index, histological differentiation, nuclear grade, keratinisation, desmoplasia, growth pattern, inflammation, tumour emboli in peripheral vessels, keratins 6, 13, 19 immunohistochemical expression, cytofluorometric ploidy and S-phase. In multivariate analysis (Cox), only age and nodal status had a significant impact on the overall survival, whereas T stage was the only significant factor associated with locoregional failure. The cumulative incidence of metastases was correlated not only with age, T and N stage, but also with histological differentiation. All the other histological and biological factors studied failed to provide further prognostic information. These findings may help to select patients with high metastatic risk.

A comparison of cellular proliferation markers in squamous cell carcinoma of the head and neck

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.(ABSTRACT TRUNCATED AT 250 WORDS)