Epidemiological and diagnostic aspects of oral squamous cell carcinoma

Oral cancer diagnostics: An overview

Cancer was first mentioned in medicine texts by Egyptians. Ancient Indians studied oral cancer in great detail under Susruta. Cancer has continued to be a challenge to physicians from ancient times to the present. Over the years, cancer underwent a shift in management from radical surgeries toward a more preventive approach. Early diagnosis is vital in reducing cancer-associated mortality especially with oral cancer. Even though the mainstay of oral cancer diagnosis still continues to be a trained clinician and histopathologic examination of malignant tissues. Translating innovation in technological advancements in diagnostic aids for oral cancer will require both improved decision-making and a commitment toward optimizing cost, skills, turnover time between capturing data and obtaining a useful result. The present review describes the conventional to most advanced diagnostic modalities used as oral cancer diagnostics. It also includes the new technologies available and the future trends in oral cancer diagnostics.

Overexpression of phosphorylated nuclear factor-kappa B in tonsillar squamous cell carcinoma and high-grade dysplasia is associated with poor prognosis

Intracellular signals along the epidermal growth factor receptor (EGFR)-Akt-nuclear factor-kappa B (NF-kappaB) pathway have been associated with carcinogenesis in various malignant neoplasms. This investigation was to evaluate the expression of EGFR, phosphorylated(p)-Akt and p-NF-kappaB and correlate them with clinical outcomes in patients with squamous cell carcinoma of the tonsil. A total of 45 patients with squamous cell carcinoma of the tonsil were studied by immunohistochemistry to evaluate the expression levels of EGFR, p-Akt and p-NF-kappaB. Results for squamous cell carcinoma of the tonsil were compared with those for associated high-grade dysplasia and adjacent normal appearing epithelium, when present. In addition, tonsillar epithelium from non-neoplastic specimens of age-matched patients also was stained for the same markers. High-grade dysplasia and squamous cell carcinoma of the tonsil demonstrated a similar pattern of expression, which differed from the pattern seen in the adjacent normal epithelium and tonsillar epithelium from normal controls (an overexpression for each of these three protein analytes in high-grade dysplasia and squamous cell carcinoma of the tonsil as demonstrated by immunohistochemistry). When markers from squamous cell carcinoma of the tonsil were correlated with survival status, only increasing levels of p-NF-kappaB immunoreactivity (a relative overexpression) were statistically significant predictors of poor survival. No markers in squamous cell carcinoma of the tonsil were significantly related to rate of recurrence. When analyzing marker scores from tissue with high-grade dysplasia, relative overexpressions of both p-Akt and p-NF-kappaB were significantly related to poor survival. Additionally, increasing levels of p-NF-kappaB immunopositivity from tissue with high-grade dysplasia were also significantly related to rate of recurrence. In summary, p-NF-kappaB, overexpressed in high-grade dysplasia and squamous cell carcinoma of the tonsil, is associated with worse prognosis in terms of high recurrence and poor survival, respectively. This significant finding in patients with squamous cell carcinoma of the tonsil, in combination with previous animal and in vitro studies, suggests that p-NF-kappaB represents a potential therapeutic target in head and neck squamous cell carcinoma.

Squamous cell carcinoma of the oral cavity: the results of the surgical and non-surgical therapeutic modalities in a consecutive series of 156 patients treated in Copenhagen county

A retrospective study on patients, treated for intraoral squamous cell carcinoma in Copenhagen county, is reported. The material included 156 patients, 66 females and 90 males. Age at diagnosis varied between 35 and 95 years with a mean of 65 years. Mean age of females/males was 70/62 years. Twelve therapeutic modalities were performed; surgery, radiotherapy, chemotherapy and different combinations of these. Three and five years crude survival were 43% and 37%. Three and five years crude survival rates were 70% and 61% for patients in stage I, 39% and 32% for patients in stage II, 29% and 16% for patients in stage III and 19% and 17% for patients in stage IV. The results are similar to those achieved in other centers. Since no significant improvement has been noted in patient survival during the last 5-6 decades and since the therapeutic morbidity has not always been acceptable to the patients, other therapeutic principles such as the so-called minimal invasive therapy should be considered in future treatment of intraoral cancer.

Cancer of the mobile tongue in Mexico. A retrospective study of 170 patients

Histological reports of 170 patients with cancer of the mobile tongue between 1977 and 1989 were identified at the Instituto Nacional de Cancerología (INCan), in Mexico City. Demographic, clinical and histological information was retrospectively reviewed. Chi-square, Student's t-test and Wilcoxon rank-sum test were applied for comparisons, and Kaplan-Meier curves, log-rank test and Cox proportional hazards for survival analysis. Of the 161 patients with mobile tongue squamous cell carcinoma (MTSCC), 104 (65%) were males and 57 (35%) were females. The mean age was 60 years old (range 19-91). T1 and T2 lesions comprised 35%, T3 and T4 lesions 65%. There was a statistically significant association between size of the tumour and lymph node involvement (P < 0.0001). The proportion of cases with advanced disease was 80% for males and 57% for females (P = 0.008). The 5-year survival rate was 16% (CI 10.2-22.8%). Cancer of the mobile tongue in Mexico still has a poor prognosis. Efforts should be made to reduce the delay in diagnosis of MTSCC, in order to increase the cure rates and improve the quality of life of the patients.

Changes in cytokeratins following treatment of hamster cheek pouch epithelia with hyperplastic or neoplastic agents

The effects of four different hyperplastic agents and of the carcinogen DMBA on cytokeratin expression in hamster cheek pouch epithelia were compared. Reversible hyperplasia was produced by the application of either oil of turpentine, vitamin A or TPA. No hyperplastic changes were produced by application of EPP. Apart from the transient appearance of a 45 kDa cytokeratin in one group treated with vitamin A, the immunohistochemical staining patterns and immunoblot profiles of cytokeratins from cheek pouches treated with each of the hyperplastic agents were identical to controls. Following application of DMBA, the cytokeratins stained with increased intensity in the spinous and granular cell layers. This was associated with increased amounts of 42-56 kDa cytokeratins and decreased production of 62-75 kDa cytokeratins. Monoclonal antibody AE1 detected a 45 kDa cytokeratin in extracts of DMBA-treated epithelia that was not detected in untreated epithelial extracts. Monoclonal antibody AE3 detected an additional 54 kDa cytokeratin band in extracts of DMBA-treated epithelia. These cytokeratin changes were present in preneoplastic epithelia and maintained in neoplastic epithelia.

Production of a suppressor of lymphocyte proliferation by two human oral carcinoma cell lines

This study examined the production of an immunosuppressive factor by the KB and H191 human oral squamous carcinoma cell lines. Conditioned media (CM) from both cell lines markedly inhibited mitogen- and alloantigen-induced proliferation of normal human and rat peripheral blood lymphocytes. By contrast, the proliferation of an exponentially-growing fibroblast cell line remained unchanged by CM. The immunosuppressive factor appeared to act after lymphocyte commitment as indicated by continued blast cell formation, the failure of CM to suppress resting lymphocytes and the fact that CM caused maximum inhibition of lymphocyte proliferation 72 h after the addition of PHA. The addition of exogenous IL-2 did not counteract lymphocyte suppression. Inclusion of indomethacin and isoniazid during cell culture did not significantly alter the degree of suppressive activity. Mycoplasma contamination was absent and CM did not act directly with the thymidine or mitogen. The factor was heat stable at 50 degrees C, acid labile and had a molecular weight in excess of 300 kDa. The results demonstrate that human oral squamous carcinoma cell lines produce an immunosuppressive factor that may have a role in tumour evasion of the host immune response.

Prognostic factors in oral cavity carcinomas

This retrospective study of 176 patients with oral cavity carcinoma showed that nearly 60% of the patients presented with an advanced stage of disease. The duration of symptoms was shorter in patients with a large tumour than with a small (p less than 0.001) and in patients with metastases than in those without (p less than 0.01). Lymph node metastases were more common in large tumours (p less than 0.01), in tumours with high malignancy grading (p less than 0.05) and in non-diploid tumours (p less than 0.001). The presence of lymph node metastases (p less than 0.001), tumour size (p less than 0.01) and tumour DNA ploidy (p less than 0.005) were the only parameters that significantly influenced survival (Cox regression analysis).

Epidemiologic studies of oral mucosal conditions--methodologic issues

The methods used in the international English-language literature of epidemiologic investigations of oral mucosal conditions were reviewed. Methods used to study leukoplakia, lichen planus, recurrent herpes labialis, recurrent aphthous ulcers, geographic tongue and candidiasis are highlighted. In addition, studies of the full range of pathologies documented in a population were reviewed. The methodologic issues raised by the epidemiologic literature as well as those to be considered for future studies of oral mucosal conditions are presented. Emphasis is placed on study population selection, diagnostic criteria development, type and training of examiners, risk factor assessment and issues related to data collection, analysis and reporting.

Squamous cell carcinoma of the oral cavity. A review of 176 cases with application of malignancy grading and DNA measurements

This retrospective study comprised 176 patients with squamous cell carcinoma of the oral cavity treated at The Linköping University Hospital over a 19-year period. Clinical parameters, microscopic malignancy grading (according to Jakobsson et al. and Glanz and Eichhorn), DNA cytofluorometry, analysis of therapeutic modalities and statistics regarding survival and prognosis are reported. The mean age was 70 years with a male: female ratio of 1.3:1 One hundred and four patients had T1 or T2 tumours and 109 an N0 neck. Cervical lymph node metastases were more frequent in patients with larger tumours (T3 + T4) than in those with smaller (T1 + T2) (P less than 0.01), in tumours with a high malignancy grading compared to those with a low (P less than 0.05) and in DNA non-diploid tumours compared to diploid ones (P less than 0.001). The aneuploid tumours responded better to preoperative radiotherapy than did diploid (P less than 0.01) or polyploid (P less than 0.05) tumours. Eighty-nine per cent of the recurrences occurred within 1 year of initial therapy. Secondary treatment was successful in 15 of 37 (41%) patients in whom the tumour recurred either at the primary site or in regional lymph nodes, but only in 1 of 8 (12%) with recurrences in both locations. Surgery alone or combined with radiotherapy resulted in equivalent survival rates for tumours in stages I and II. In advanced stages combined radiotherapy and surgery gave better survival figures than either modality alone (P less than 0.01; Kaplan-Meier). The presence of lymph node metastases (P less than 0.001), tumour size (P less than 0.01) and tumour ploidy (P less than 0.005) were the only clinical and histological parameters that significantly influenced survival (Cox regression analysis). Twenty-four patients developed a secondary primary malignancy; 21 of these were located in the aerodigestive tract.

Expression of oncogenes in human tumours with special reference to the head and neck region

A major recent advance in cancer research has been in the field of oncogenes. Oncogenes are genes with a proven cancer association and which appear to be particularly implicated in cellular regulation and proliferation. The oncogenic potential of specific cellular genes has now been recognised and this has influenced current thinking concerning the initiation of carcinogenesis. The specific role of an oncogene is still incompletely understood but research with one particular oncogene (ras) has demonstrated that it can be involved in more than one stage of multi-step carcinogenesis. New techniques are being developed and evaluated to determine the expression of specific oncogenes in normal and neoplastic tissues, with a view to using them in future diagnostic immuno-histopathological methods. This review describes the concept of oncogenes and discusses their role in the development of neoplasia. The results of the expression of various oncogenes in human malignancies with special reference to the head and neck regions are discussed. Finally, the future prospects of this research field are examined their and its possible implications in cancer therapy.