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

Radiomic Analysis of Tumour Heterogeneity Using MRI in Head and Neck Cancer Following Chemoradiotherapy: A Feasibility Study

Objectives

To evaluate interval changes in heterogeneity on diffusion-weighted apparent diffusion coefficient (ADC) maps and T1-weighted post-gadolinium (T1w post gad) MRI in head and neck carcinoma (HNSCC), with and without chemo-radiotherapy (CRT) response.

Methods

This prospective observational cohort study included 24 participants (20 men, age 62.9 ± 8.8 years) with stage III and IV HNSCC. The primary tumour (n = 23) and largest lymph node (n = 22) dimensions, histogram parameters and grey-level co-occurrence matrix (GLCM) parameters were measured on ADC maps and T1w post gad sequences, performed pretreatment and 6 and 12 weeks post CRT. The 2-year treatment response at primary and nodal sites was recorded. The Wilcoxon signed-rank test was used to compare interval changes in parameters after stratifying for treatment response and failure (p < 0.001 statistical significance).

Results

23/23 primary tumours and 18/22 nodes responded to CRT at 2 years. Responding HNSCC demonstrated a significant interval change in ADC histogram parameters (kurtosis, coefficient of variation, entropy, energy for primary tumour; kurtosis for nodes) and T1w post gad GLCM (entropy and contrast in the primary tumour and nodes) by 6 weeks post CRT (p < 0.001). Lymph nodes with treatment failure did not demonstrate an interval alteration in heterogeneity parameters.

Conclusions

ADC maps and T1w post gad MRI demonstrate the evolution of heterogeneity parameters in successfully treated HNSCC by 6 weeks post CRT; however, this is not observed in lymph nodes failing treatment.

Advances in Knowledge

Early reduction in heterogeneity is demonstrated on MRI when HNSCC responds to CRT.

Clinical and histopathologic parameters in survival of oral squamous cell carcinoma

OBJECTIVE

The aim of this study was to assess the relevance of clinical and histopathologic parameters on survival of oral squamous cell carcinoma (OSCC) patients in Sri Lanka.

STUDY DESIGN

A cohort of 193 previously diagnosed OSCC patients were followed for up to 5 years. Clinical and histopathologic parameters were analyzed regarding local recurrence and 5-year survival after treatment.

RESULTS

Site, stage, local recurrence, degree of differentiation, degree of keratinization, pattern of invasion, and status of the excision margins showed a significant association with the 5-year survival (P < .05). Multivariate analysis identified stage, pattern of invasion, and status of the excision margins as true independent prognostic indicators of OSCC. Pattern of invasion was the best prognosticator of both local recurrence and overall survival in the Cox regression model (P < .001).

CONCLUSIONS

Stage, pattern of invasion, and status of the excision margins are superior prognostic indicators of OSCC compared with other parameters.

Pretreatment diffusion-weighted and dynamic contrast-enhanced MRI for prediction of local treatment response in squamous cell carcinomas of the head and neck

OBJECTIVE

The objective of our study was to predict response to chemoradiation therapy in patients with head and neck squamous cell carcinoma (HNSCC) by combined use of diffusion-weighted imaging (DWI) and high-spatial-resolution, high-temporal-resolution dynamic contrast-enhanced MRI (DCE-MRI) parameters from primary tumors and metastatic nodes.

SUBJECTS AND METHODS

Thirty-two patients underwent pretreatment DWI and DCE-MRI using a modified radial imaging sequence. Postprocessing of data included motion-correction algorithms to reduce motion artifacts. The median apparent diffusion coefficient (ADC), volume transfer constant (K(trans)), extracellular extravascular volume fraction (v(e)), and plasma volume fraction (v(p)) were computed from primary tumors and nodal masses. The quality of the DCE-MRI maps was estimated using a threshold median chi-square value of 0.10 or less. Multivariate logistic regression and receiver operating characteristic curve analyses were used to determine the best model to discriminate responders from nonresponders.

RESULTS

Acceptable χ(2) values were observed from 84% of primary tumors and 100% of nodal masses. Five patients with unsatisfactory DCE-MRI data were excluded and DCE-MRI data for three patients who died of unrelated causes were censored from analysis. The median follow-up for the remaining patients (n = 24) was 23.72 months. When ADC and DCE-MRI parameters (K(trans), v(e), v(p)) from both primary tumors and nodal masses were incorporated into multivariate logistic regression analyses, a considerably higher discriminative accuracy (area under the curve [AUC] = 0.85) with a sensitivity of 81.3% and specificity of 75% was observed in differentiating responders (n = 16) from nonresponders (n = 8).

CONCLUSION

The combined use of DWI and DCE-MRI parameters from both primary tumors and nodal masses may aid in prediction of response to chemoradiation therapy in patients with HNSCC.

Análise de sobrevida global em pacientes diagnosticados com carcinoma de células escamosas de boca no INCA no ano de 1999

O carcinoma de células escamosas de boca compreende cerca de 90 a 95% de todas as neoplasias malignas da boca e é um dos tipos de câncer mais frequentes no Brasil. O índice de sobrevida em 5 anos é baixo e permaneceu estável nas últimas décadas, apesar dos avanços nas terapias. O objetivo deste estudo foi analisar o perfil e a sobrevida global dos pacientes diagnosticados com carcinoma de células escamosas de boca no ano de 1999 no Instituto Nacional de Câncer. Dos 320 pacientes incluídos no estudo, 79,4% eram homens. A idade média foi de 56,7 anos, e 82,2% deles fumavam e/ou bebiam. A língua, seguida do assoalho de boca foram os locais mais acometidos. A maioria (68,9%) dos pacientes foi diagnosticada em estádios tardios e submetida à radioterapia exclusiva (53,6%). A sobrevida média no período do estudo foi de 29,4 meses. Os pacientes dos estádios iniciais apresentaram maior sobrevida, assim como aqueles submetidos apenas à cirurgia como forma de tratamento e os que não apresentaram linfonodos acometidos ao diagnóstico. Tumores localizados em palato duro e mucosa jugal apresentaram pior prognóstico. Foram fatores preditivos independentes de melhor sobrevida os tumores T1 ou T2 (p=0,001), sem acometimento de linfonodos (p=0,012) e não localizados em mucosa jugal (p=0,021). O diagnóstico do câncer oral ainda se faz em estádios tardios, o que influencia negativamente a sobrevida global dos pacientes. Maior ênfase deve ser dada à capacitação dos profissionais para o reconhecimento precoce do câncer e à conscientização da população de risco.

Mapping of Ki-67 protein distribution on whole organ serial sections of the larynx

CONCLUSIONS

Immunostaining of whole organ serial sections of the larynx is feasible and will allow analysis of cellular alterations in the undisturbed anatomical context of whole organ serial sections of the larynx.

OBJECTIVES

Whole organ serial sections of the larynx have to date been used for conventional macroscopic evaluation of laryngeal tissues. The aim of this study was to establish a protocol for immunohistochemistry of whole organ sections of the larynx.

MATERIALS AND METHODS

Five laryngectomy specimens were obtained during surgery for advanced laryngeal carcinoma. Using a novel method for paraffin embedding, we chose the proliferation marker Ki-67 antigen as a model target for immunoreactivity on serial sections.

RESULTS

We were able to produce whole organ serial sections that could then be immunostained for Ki-67. A complete mapping of proliferating cells throughout the tumour, at the tumour front and in skip lesions was subsequently obtained.

Molecular markers of head and neck squamous cell carcinoma: promising signs in need of prospective evaluation

BACKGROUND

The aim of this article is to review recent developments in the biological understanding of head and neck squamous cell carcinomas.

METHODS AND RESULTS

We describe the markers according to their function and their prognostic or predictive roles. Some associations can be found between molecular markers and invasiveness, aggressiveness, degree of differentiation, and tumor stage, but only a few clinical studies have shown an impact on prognosis. In addition, despite an increasing number of articles relating to this topic, the small number of patients included in the studies reported reduces the clinical implications of these results. Few studies applied a more comprehensive molecular analysis approach, such as DNA microarrays or differential expression profiling by polymerase chain reaction, to identify a combination of markers that could be more informative than a single molecular marker.

CONCLUSION

Some progress has been made with respect to molecular markers and head and neck cancers. Translational and prospective, hypothesis-driven research must proceed with sufficient rigor to facilitate the clinical applicability of such results.

Immunohistochemistry of whole-organ sections of advanced human laryngeal cancer

Whole-mount sections have been in the interest of laryngologists for long time. The aim of this study was to demonstrate the technical aspects of processing horizontal whole-mount sections of advanced laryngeal cancer specimens after total laryngectomy. Those sections may provide new insights in the biology of laryngeal cancer. Six excised human larynges were block-embedded in paraffine. Serial sections were obtained as thin as 9 mum. Sections were stained by Giemsa and standard immunohistochemistry protocols with commercial antibodies against Cytokeratine5/6, Ki-67, Topoisomerase IIalpha, and p53. Four high-power fields were selected randomly in each section of a surface grid and the percentage of positive tumor cells was noted for each antibody in the respective field. Morphometric surface maps of protein expression were generated for each parameter. The tissues remained intact without major artifacts. Specific characteristics of the tumors were identified after evaluation of the whole-mount sections. Staining of cytokeratine was homogenous, whereas nuclear markers showed a distinct heterogeneity in the respective staining patterns. By analyzation of color-coded fusion images the spatial expression of the respective antibodies could be visualized.

Expression of Bcl-2 but not Bax has a prognostic significance in tongue carcinoma

BACKGROUND

Among the molecular mechanisms involved in carcinogenesis, defects in the regulation of programmed cell death (apoptosis) make important contributions to the pathogenesis and progression of cancer. Apoptosis regulatory genes include the antiapoptotic bcl-2 gene and the proapoptotic bax gene. The aim of this study was to determine the spectrum of Bax and Bcl-2 expression, and to correlate these findings with clinicopathologic variables and prognosis.

METHODS

In this study we have evaluated the immunohistochemical expression of Bcl-2 and Bax proteins in a series of 35 squamous cell carcinomas of the tongue.

RESULTS

Immunoreactivity for Bax was detected in 37.1% and for Bcl-2 in 8.6% of cells, and for both proteins the staining was cytoplasmic and granular. Bcl-2 and Bax expression was mainly seen in peripheral cells of epithelial tumor islands with decreasing immunoreactivity toward the center of the neoplastic nests. Bax immunoexpression was significantly correlated with histologic grading (P=0.05), but not with the remaining clinicopathologic variables. Bcl-2 immunoreactivity was significantly correlated with N-stage (P=0.01) and survival. Patients with Bcl-2-negative tumors [mean survival: 73.97 months; 95% confidence interval (CI): 59-88] vs. Bcl-2-positive ones (mean survival: 17.67 months; 95% CI: 6-29) had a longer survival (P=0.01; odds ratio=6.9).

CONCLUSIONS

Bcl-2 is associated with aggressive disease, neck lymph node metastasis, and poor prognosis. Whereas Bax is related with histologic grade.

Selective reporting biases in cancer prognostic factor studies

BACKGROUND

Nonreported and selectively reported information and the use of different definitions may introduce biases in the literature of prognostic factors. We probed these biases in a meta-analysis of a prognostic factor for head and neck squamous cell cancer (HNSCC) mortality that has drawn wide attention--the status of the tumor suppressor protein TP53.

METHODS

We compared results of meta-analyses that included published data plus unpublished data retrieved from investigators; published data; and only published data indexed with "survival" or "mortality" in MEDLINE/EMBASE, with or without standardized definitions. We also evaluated whether previously published meta-analyses on mortality predictors for various malignancies addressed issues of retrieval and standardized information. All statistical tests were two-sided.

RESULTS

For the 18 studies with 1364 patients that included published and indexed data, we obtained a highly statistically significant association between TP53 status and mortality. When we used the definitions preferred by each publication, the association was stronger (risk ratio [RR] = 1.38, 95% confidence interval [CI] = 1.13 to 1.67; P = .001) than when we standardized definitions (RR = 1.27, 95% CI = 1.06 to 1.53; P = .011). The addition of 13 studies with 1028 subjects that included published but not indexed data reduced the observed association (RR = 1.23, 95% CI = 1.03 to 1.47; P = .02). Finally, when we obtained data from investigators (11 studies with 996 patients) and analyzed it with all other data, statistical significance was lost (RR = 1.16, 95% CI = 0.99 to 1.35; P = .06). Among 18 published meta-analyses of 37 cancer prognostic factors, 13 (72%) did not use standardized definitions and 16 (89%) did not retrieve additional information.

CONCLUSIONS

Selective reporting may spuriously inflate the importance of postulated prognostic factors for various malignancies. We recommend that meta-analyses thereof should maximize retrieval of information and standardize definitions.

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.

Immunohistochemical expression of CA19-9 and CA125 in mucoepidermoid and adenoid cystic carcinomas of the salivary gland

This study examined the immunohistochemical expression of carbohydrate antigens CA19-9 and CA125 and their relationship to various biological parameters in 27 mucoepidermoid carcinomas (MEC) and 18 adenoid cystic carcinomas (ACC) arising from salivary glands. The series showed higher immunopositivity for CA125 (67% for MEC; 33% for ACC) than for CA19-9 (59% for MEC; 11% for ACC). CA19-9 epitope was mainly expressed in cystic (MEC) and cribriform/tubular (ACC) components of carcinoma tissues. Solid components in MEC occasionally showed positive staining for CA19-9. CA125 was evenly expressed in both ACC and MEC tissues regardless of their different histological components. The positive expression of CA19-9 and CA125 in the carcinoma tissues did not influence the clinical course of patients with MEC and ACC. A significant relationship was only demonstrated between the immunohistochemical expression of CA125 and the low proliferative activity (LI) evaluated by Ki-67 immunohistochemistry. However, no significant relationship was found between LI and the patients' clinical course. These results suggest that the immunostaining for CA19-9 and CA125 provide no reliable data to predict the clinical course of patients with MEC and ACC of the salivary glands.

The association between glutathione S-transferase P1 genotype and plasma level in head and neck cancer

OBJECTIVES/HYPOTHESIS

Glutathione S-transferase P1-1 (GSTP1-1) is an important enzyme because it plays a major role in many detoxification reactions, including tobacco-related metabolic products. GSTP1-1 is the most abundant of all glutathione S-transferase (GST) enzymes in normal human head and neck epithelium, whereas it is overexpressed in head and neck malignancies. At least three different GSTP1 genotypes exist, AA, AB, and BB, which have been correlated with reduced enzyme activity. Many authors have studied the GSTP1 genotypes in relation to the risk for human head and neck squamous cell carcinoma (HNSCC). A correlation between GSTP1-1 genotype and GSTP1-1 plasma levels has not been made before. We investigated the correlation between GSTP1 genotype and GSTP1-1 plasma levels.

STUDY DESIGN

To evaluate the possible association between the genetic polymorphisms in GSTP1 and the phenotypic expression (GSTP1-1 plasma levels) in patients with HNSCC.

METHODS

GSTP1 genotype and GSTP1-1 plasma level were established in 87 patients with HNSCC and 51 patients with benign head and neck lesions who served as control subjects.

RESULTS

For all GSTP1 genotypes (AA, AB, and BB) in patients with HNSCC, the mean plasma GSTP1-1 values were significantly higher compared with the control subjects. There was no significant difference in the plasma GSTP1-1 levels between the different genotypes in patients with HNSCC.

CONCLUSION

There is no association between GSTP1 genotype and GSTP1-1 plasma levels in patients with head and neck cancer.

The relationship of epidermal growth factor receptor levels to the prognosis of unresectable pharyngeal cancer patients treated by chemo-radiotherapy

The aim of this study was to analyse prognostic factors for time to treatment failure (TTF) and overall survival (OS) in patients with unresectable cancer of the pharynx. A twice daily (b.i.d.) radiotherapy with concomitant cisplatin-5-fluorouracil chemotherapy was administered to 77 consecutive patients (68 males, 9 females; median age: 56 years). The studied factors were: age, gender, tumour differentiation, tumour volume, initial hemoglobin level, karnofsky index (KI), primary tumour location, T, N, epidermal growth factor receptor (EGFR) level in the tumour (fmol/mg protein). KI and EGFR level were significant predictors in a multivariate analysis for TTF (P=0.004 and P=0.0001) and OS (P=0.004 and P=0.0001). In order to select subgroups with different outcomes, a stratification of patients was performed based on the EGFR value: patients with tumour EGFR levels <35 fmol/mg protein, between 35 and 275 fmol/mg protein and >275 fmol/mg protein had 95%, 51% and 16% 3 year OS rates, respectively (log rank test; P=0.0001). Interestingly, for patients exhibiting a complete response (CR) after concomitant b.i.d. chemo-radiotherapy, patients with EGFR levels <35 fmol/mg protein were all alive at 3 years; in contrast, there was only 70 and 13% 3 year survival rates for patients with EGFR tumour levels between 35 and 275 fmol/mg protein and above 275 fmol/mg protein, respectively. EGFR determination appears to be a powerful prognostic parameter in unresectable pharyngeal cancer patients treated by concomitant chemo-radiotherapy.

[Fluorine-18]fluorodeoxyglucose positron emission tomography, DNA ploidy and growth fraction in squamous-cell carcinomas of the head and neck

BACKGROUND

Positron emission tomography (PET) offers an opportunity to examine noninvasively cellular functions with different tracers. [(18)F]Fluorodeoxyglucose (FDG) is most commonly used in identifying malignant tumors. Several tumor biologic characteristics (tumor cell viability, growth faction, treatment response to radiation, cell membrane dysfunction, recurrence rate) are suggested to be characterized by [(18)F]FDG PET. The aim of this study was to assess which other tumor biologic characteristics of squamous-cell carcinoma of the head and neck are correlated with [(18)F]FDG PET.

METHODS

[(18)F]FDG PET was performed in 14 patients with squamous-cell carcinomas of the upper digestive tract (TNM classification T(2)-T(4), N(1)-N(3)). After attenuation correction, predefined areas of the tumor were semiquantitatively analyzed by the technique of the region of interest and calculated as standard uptake values (SUV). Afterwards, 5 biopsies of different tumor regions were obtained during endoscopy in each patient under general anesthesia, and a correlation between SUV of [(18)F]FDG PET and tumor biologic parameters was attempted. These parameters included: quantitative DNA measurements (i.e. 2c deviation index, 5c exceeding rate), immunohistochemical assessment of growth fraction (i.e. Ki67-MIB-1, PCNA) along with morphological tumor front grading.

RESULTS

The results revealed a marked variation of proliferation and cellular differentiation in various regions of the tumor for all parameters examined. There was a close correlation between [(18)F]FDG uptake and growth fraction (r = 0.83 for Ki67-MIB-1 and r = 0.8 for PCNA). A poor correlation was found between DNA aneuploidy (r = 0.4) or tumor front grading (r = 0.12) and [(18)F]FDG uptake.

CONCLUSIONS

Our results confirm previous clinical and histologic observations that squamous-cell carcinomas of the upper digestive tract are heterogeneous tumors. Ki67 antigen, which has been shown to be of predictive value for proliferation and individual prognosis, correlated with [(18)F]FDG uptake. Using [(18)F]FDG PET, the main proliferation centers of inhomogeneous squamous-cell carcinomas could be identified with possible clinical implications for patient management.

Glutathione S-transferases as emerging therapeutic targets

Glutathione S-transferases (GST) represent a large family of Phase II detoxification enzymes widely expressed in animals and plants. These enzymes catalyse the conjugation of glutathione with some endogenous molecules and a broad range of exogenous substrates including various anticancer drugs. Due to high expression of GSTs in tumours when compared to normal tissues and their high level in plasma from cancer patients, these enzymes are considered to be cancer markers. Their involvement in resistance to anticancer drugs and an inverse correlation between expression and prognosis in many tumours provided a rationale for the design of inhibitors and prodrugs to enhance therapeutic index. The first generation of GST inhibitors included ethacrynic acid and showed promising potentiating activity in vitro but lack of isoenzyme specificity and diuretic side effects restricted clinical use. Novel GST inhibitors include glutathione analogues and demonstrate better specificities with fewer limiting toxicities. One lead compound is a potent inhibitor of the GSTP1-1 isoform in both cell lines and animal models. A GSTP1-1 activated prodrug has also been developed. Testing of the preclinical and clinical efficacy of these agents is presently in progress. Their rational design provides a promising new approach to targeting tumour-specific characteristics in a manner consistent with improving therapeutic index.

Molecular markers in head and neck squamous cell carcinoma: their biological function and prognostic significance

Head and neck squamous cell carcinoma affects more than 500,000 people worldwide each year. Despite optimal treatment with surgery, irradiation, and chemotherapy, disease recurrence and progression remains a common and challenging oncological problem. Recently, interest has developed in identifying novel molecular markers that allow identification of those patients at increased risk for locoregional recurrence and death. This article reviews several such molecular markers studied in head and neck cancer, including p53, angiogenesis-related markers, cyclin D1, and epidermal growth factor receptor. The biological function of these markers and the potential clinical implications are discussed. The purpose of this review is to update the otolaryngologist on a rapidly emerging segment of applied translational research in our field.

Squamous carcinoma of the head and neck: molecular mechanisms and potential biomarkers

Squamous cell carcinoma (SCC) of the head and neck remains a major health problem worldwide. Recent advances in cell biology suggest that cancer results from the accumulation of specific genetic mutations, many of which have now been identified. These mutations can cause the activation of genes that promote cellular proliferation or inhibit cell death (oncogenes), or they may inactivate genes that inhibit proliferation or promote cell death (tumour suppressor genes). Although there is no known set sequence of events leading to the formation of SCC of the head and neck, there is evidence that many of the genomic mutations implicated in other forms of cancer have an aetiological role in these tumours. Certain viruses, notably Epstein-Barr virus and some types of human papillomaviruses, are causally related to some head and neck cancers. There is now the prospect of using molecular markers to achieve earlier diagnosis and to aid in the prediction of both tumour behaviour and likely responses to particular treatment modalities.

Influence of p53 and bcl-2 on proliferative activity and treatment outcome in head and neck cancer patients

Knowledge about the influence of biomarkers on cell proliferative activity might explain differences in radiosensitivity between head and neck tumors and might improve patient selection for the most optimal treatment strategy. p53 and bcl-2 protein expression were determined immunohistochemically in 56 head and neck cancer patients, treated by surgery only in five cases and by radiotherapy, with or without surgery, in 51 cases. Relationships with various cell proliferation markers, determined by flow-cytometry (G1-phase fraction, S-phase fraction, BrdUrd-labeling index, duration of S-phase and potential doubling time) were investigated. Associations between these cell proliferation parameters, on the one hand, and both p53 and bcl-2, on the other, were not found. Furthermore, p53 and bcl-2 expression were both not related to clinicopathological parameters (T- and N-stage, site, grade) and did not affect loco-regional recurrence-free survival and/or disease-free survival. We could not find a prognostic value for both p53 and bcl-2 protein expression to differentiate radiosensitive from radioresistant head and neck tumors.

Surfing prognostic factors in head and neck cancer at the millennium

The ability to reliably predict cancer outcome could tailor therapy to the aggressiveness of the tumour to achieve the best results in terms of loco-regional control, overall survival and quality of life. Retrospective and prospective clinical trials involving large series of patients have validated some predictive clinical and pathological factors, whereas the utility of many other prognostic factors has not been established. This has led to some confusion in clinical practice. In order to clarify the significance, role and cost of these prognostic factors we carried out a Medline search of all papers published between 1993 and 1998 concerning the reliability and cost of markers with prognostic significance, in head and neck squamous cell carcinoma, and assessed the results according to a number of criteria relating to reliability and cost. Regarding reliability we classified prognostic factors into: (1) those with a proven significance based on the fact that they were unanimously reported as having an independent statistical correlation with outcome and prognosis; and (2) those for which results were not unanimous, and which significance is still controversial. Cost analysis showed a substantial difference between validated tests which are of low cost and experimental tests which are expensive. Based on these data regarding both the reliability and cost of each prognostic factor, we propose guidelines for their use in clinical practice in the year 2000.

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.