INTRODUCTION

The increase in number of cases of high morbidity malignant neoplasm there were diagnosed and treated determines the high level of mortality of malignant neoplasm in general and those of the base of the tongue in particular1. In Brazil, 305,300 new cases of cancer were diagnosed in 2001 and 117,500 died of the disease in the period2. It is due, among other factors, to the increase in the average life of the world population, the result of health promotion and recovery programs, environmental factors and changes in behavior, all responsible for carcinogenesis. Considering the listed variables, it is evident that epidemiological and statistical factors are important for the definition of early diagnosis and prevention. As to malignant oral cavity (3%) and oropharynx (1%) neoplasms, the latter is characterized by insidious onset and early uni or bilateral neck metastases3. Kanda (2001)4, from 1977 to 2000, observed a predominance of cancer of the palatine tonsil (47.2%)4, followed by tongue base (33.5%), soft palate (16.0%), and posterior wall (4.2%)4. As to tongue base neoplasm, 90 to 95% of the cases are squamous cell carcinomas (SCC), predominantly in males on the 5th decade of life3, 4, 5, 6, 7, 8, being directly related to consumption of alcohol and tobacco, diet, occupation, viral infection and genetic abnormalities9, 10.

In Brazil, there are 36 million smokers of which 40% are in São Paulo, being that smoking cessation figures amount to 3% every year, and considering alcohol abuse, 1.3 billion liters of sugar cane fermented drinks - aguardente - are produced annually11. For the low income population, who is predominant in the incidence of this neoplasm, the consumption of distilled drinks of unknown origin is common, whose manufacturer normally use carcinogenic chemical substances that are not included in products that comply with quality control manufacturing practices. In addition, oropharynx carcinoma has a late diagnosis because of absence of early symptomatology, poor symptomatology or poor professional training (physicians, dentists). Considering such factors, base tongue SCC are diagnosed in advanced stages (stages III and IV), when therapeutic procedures are no longer very effective.
In view of such initial considerations, we tried to correlate clinical and epidemiological data and to identify the risk groups for the development of this neoplasm, as well as to contribute to the prevention and early diagnosis of base tongue SCC.

MATERIAL AND METHOD

We conducted a descriptive retrospective study for 290 patients with SCC of the base of the tongue, from the Department of Head and Neck Surgery and Otorhinolaryngology, Hospital Heliópolis, Hosphel, São Paulo, from 1977 to 2000. The variables analyzed were age, race, occupation, main complaint, duration of complaint, habits and exposure (alcohol tobacco), oral hygiene conditions, clinical staging (TNM), time between diagnosis and beginning of treatment.

 Gender and race: men and women, including White, Black, Asian and other ethnic groups.
 Age: as of the 4th decade of life and older than 80 years in one single group.
 Occupation: 1. Agriculture workers; 2. Industrial workers operating in areas with inhaled substances, chemicals, wood and mechanics; 3. Trade-related occupations, including professionals; 4. Housewife; 5. Retired people.
 Main complaint: first complaint and duration of evolution.
 Habits: we analyzed type, amount and duration of consumption: 1, Smoking, for non-smokers (-) or for smokers (+) of each 10 cigarettes or 2 homemade cigarettes, or cigar or pipe/day.
 Alcohol abuse: being (-) for non-consumers and (+) for each dose of distilled drink or 1 bottle of beer of 600cc or ½ bottle wine/day.
 Classification TNM: version used in 1998 associated with the palpation examination of lymph nodes levels I (submental-mandibular); II (high jugular-carotid); III (middle jugular-carotid); IV (low carotid jugular), and V (posterior neck triangle).

As to staging, we diagnosed Stage I (1.4%), II: 45 (15.5%); III (32.5%); IV :147 (50.6%).

 Interval between diagnosis and treatment: the time between the diagnosis made by biopsy and the beginning of therapy (surgical and/or radiotherapy).

Statistical Analysis:
In order to analyze the results, we selected non-parametric tests, considering the nature of the studied variables.

 Wilcoxon Test (SIEGEL; CASTELLAN JR1988): in order to compare, for each patient, smoking and alcohol drinking habits. This test was individually applied for each considered stages.
 Analysis of post variance by Kruskal-Wallis (SIEGEL; CASTELLAN JR1988): in order to compare the different stages in relation to smoking and alcohol abuse, separately.
 Kappa Concordance Test (LANDIS; KOCK 1977): aiming at studying the agreement between levels of alcohol and tobacco abuse. This test was applied separately for each stage and for each group of patients, according to the occupation.
Mc Nemar Test (REMINGTON; SCHORK 1970): as a complement to the Kappa test, it was used to compare the frequencies located above and below the diagonal agreement of Kappa test.
In all applied tests, we determined 0.05 or 5% as the null hypothesis rejection level, marking with an (*) the significant values.

RESULTS

Out of 290 patients with SCC of the tongue base, 259 were male and 31 were female subjects (8:1 ratio), being 237 White patients (81.7%), 51 Black patients (17.6%), and 2 Asians (0.7%). As to distribution by age range, there was predominance of the 6th decade of life (40.1%), followed by the 5th and 7th decades (22.7%) - table 1.

As to the occupation history, there was predominance of patients working in industry, trade and professionals (71.1%) - table 2.

To analyze time (days) between the diagnosis and the onset of treatment, most of the cases started treatment within 30 days from diagnosis (62.0%) - table 3.

As to complaint time in months, it was below 6 in 62.0%, between 6 to 12 months in 25.9% and over 12 months in 24.1%. The main symptom was odynophagia (37.2%), metastatic lymph node (21.8%), dysphagia (14.5%), tongue wound (9.0%), hoarseness (6.9%), foreign body (4.8%), reflex otalgia (3.4%), and others (2.0%) - table 4.

Next, we analyzed the amounts of alcohol and tobacco consumers (Kappa and Mc Nemar tests), clinical stage and profession (table 5), showing significant and non-significant values for the different analyzed variables.

As to time (in years) of alcohol use and smoking and its relation to staging (Wilcoxon test), we show the collected data in Table 6.

In stages I, II and IVc (small sample) it was not possible to have a statistical analysis, suggesting, however, that the smoking time should be more significant than that of alcohol consumption. To study the relation between time of alcohol and tobacco consumption and staging, we used Kruskal & Wallis test (variance analysis) - Tables 7 and 8. As to TNM staging (UICC 1998), we noticed there was a predominance of advanced cases (Table 9).






DISCUSSION

The definition of epidemiological profile of squamous cell carcinoma of the base of the tongue requires the determination of risk factors. Thus, there is unanimity about predominance in males5, 6, 12, a fact that can be observed in our sample in which we had a 8:1 ratio. As to ethnic group, the reports are in disagreement, since there are reports of the predominance in Black people9, 13, as opposed to others in which the White people were predominant14, 15 as in our study, in which we detected a 5:1 ratio. As to age range, the most affected one was the 6th decade of life (41.0%), followed by the 5th and 7th decades (22.7%) and there were no records below the age of 3rd decades of life, coinciding with the literature16, 17 (table 1).

As to occupation (table 2), there was predominance of patients connected to industrial work (36.6%), followed by trade workers and professionals (34.5%), agriculture workers (17.9%) and retired people (7.3%). Such data should be analyzed with attention, considering the absence of relevant Brazilian population samples of the distribution of neoplasm and occupations. It coincided with the reports in carpet installers14, contact with wood dust, charcoal products and cement18. As to interval between onset of symptoms and search for the physician to start treatment, there was greater frequency (62.0%) of the period between 0 and 6 months (table 3), similarly to the literature findings1, 12, 15, 19.

As to initial symptomatology (table 4), odynophagia was predominant (37.6%), followed by metastatic lymph node (21.7%) and dysphagia (14.5%). We could notice scarce initial symptomatology, which was quiet and insidious1, 19, 20, and the diagnosis indicated advanced stage neoplasm (stages III and IV), invading the adjacent and regional anatomical structures (table 5).

As to time of alcohol and smoking consumption, it was the most relevant piece of data in the study, since in all different stages, all addicted patients presented levels of mean consumption of 35 to 40 years in advanced staged (stages III and IV) for tobacco and 31 and 32 years (stages III and IV) for alcohol abuse (tables 6, 7 and 8), which led us to the conclusion that smoking is a relevant factor in morbidity of such disease. As to the association of both, it occurred in 83.8% of the cases, 11.7% of one or the other and 4.5% of none. Therefore, this association was compatible with the other reported series3, 21, 22, and there were no quantitative differences in the different stages. As to TNM staging (UICC, 1988), 50.7% were T4, 32.4% T3, 14.5% T2 and 1.4% T1, being that 21.0% N0, 13.4% N1, 43.0% N2 and 22.4% N3 (Table 9). Therefore it was noticed that ipsilateral metastases was a relevant prognostic factor, considering the natural history of the SCC of tongue base, present in 79.0% of the sample, in agreement with the literature21, 22. It enables the checking of clinical aggressiveness, in which there is predominance of the clinical stages III and IV as opposed to initial stages I and II. Together with that, parameters of primary T lesion and metastatic regional and uni or bilateral N dissemination, demonstrated the progression of the disease, in which within a relatively short time, the primary tumor advance was insidious and lymph node impairment characterized the squamous cell tongue base neoplasm, whose survival rates demonstrated little efficacy of surgical treatment and radiotherapy, isolated or combined with chemotherapy. It is also evident that through the epidemiological/clinical characteristics of neoplasm and the association with alcohol abuse and smoking, morbidity and mortality rates are high, resulting from the insidious symptomatology and the advanced staging, leading to a situation in which the therapy option becomes practically irrelevant.

CONCLUSIONS

Squamous cell carcinoma of the tongue base is more frequent in white mean in the 5th or 6th decades of life, having as risk factors smoking and alcohol abuse, being that smoking was predominant in women. The mean duration of the complaint was 6 months, with predominance of stages III and IV, being that I and II-staged cases were all alcohol abusers and/or smokers.

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1 Department of Head and Neck Surgery and Otorhinolaryngology, Hospital Heliópolis, Hosphel, São Paulo, Brazil.
2 Surgeon, Department of Head and Neck Surgery and Otorhinolaryngology, Hosphel, São Paulo.
Statistician, Department of Collective Health, University of Santo Amaro, São Paulol.
Address correspondence to: Abrão Rapoport - Rua Iramaia, n° 136 - Jd. Europa - 01450-020 - São Paulo -
Tel: (55 11)273-8223 - E-mail: cpgcp.hosphel@attglobal.net
Article submitted on September 27, 2002. Article accepted on February 13, 2003.