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Anais Brasileiros de Dermatologia

On-line version ISSN 1806-4841

An. Bras. Dermatol. vol.84 no.5 Rio de Janeiro Sept./Oct. 2009

http://dx.doi.org/10.1590/S0365-05962009000500006 

INVESTIGATION

 

Incidence of squamous cell carcinoma of the skin in the city of Tubarao (SC) – Brazil in the years 2000, 2003, and 2006

 

 

Daniel Holthausen NunesI; Liliane BackII; Ramon Vieira e SilvaIII; Vitor de Sousa MedeirosIV

IMaster in Medical Sciences. Professor of Medicine, Universidade do Sul de Santa Catarina and Universidade Federal de Santa Catarina – Tubarão (SC), Brazil
IIUndergraduate, School of Medicine, Universidade do Sul de Santa Catarina (Unisul) – Tubarão (SC), Brazil
IIIUndergraduate, School of Medicine, Universidade do Sul de Santa Catarina (Unisul) Tubarão (SC), Brazil
IVUndergraduate, School of Medicine, Universidade do Sul de Santa Catarina (Unisul) Tubarão (SC), Brazil

Mailing Address

 

 


ABSTRACT

BACKGROUND: A worldwide increasing trend in the incidence of squamous cell carcinoma of the skin has been observed but there are no studies regarding the incidence of this cancer in the Southern region of the State of Santa Catarina.
OBJECTIVES: To establish epidemiological data regarding squamous cell carcinoma of the skin in Tubarao (state of Santa Catarina).
METHODS: Anatomopathological reports, positive for squamous cell carcinoma of the skin, found in laboratories of the city of Tubarao, were analyzed regarding year, age, gender, site, histological subtype, largest diameter, and biopsy margins. The annual incidence was calculated using the number of neoplasias found and the estimated population for the years 2000, 2003, and 2006.
RESULTS: The incidence of squamous cell carcinoma of the skin per 100,000 habitants was 50.86 for the year 2000, 71.16 for 2003 and 94.39 for 2006. There was no gender dominance, the face was the most frequent location affected in both genders, and the most common histological subtype was well differentiated tumor.
CONCLUSION: The detected incidence of squamous cell carcinoma of the skin surpassed the incidence estimated in the literature. There was a considerable increase in its incidence; the variables age and location agreed with information found in the literature but gender distribution differed.

Keywords: Carcinoma, squamous cell; Carcinoma, squamous cell/epidemiology; Incidence; Skin neoplasms


 

 

INTRODUCTION

Skin cancer is the neoplasm of highest incidence in many regions of the world 1-4, including Brazil 1. The National Cancer Institute in Brazil (INCA) has estimated 116,640 new cases of non-melanoma skin cancer and 5,570 of melanoma for 2006. Added up, these numbers correspond to 26% of the total new cases of malignant neoplasm expected in the country 5. These data agrees with the world trend of increase in the incidence of skin squamous cell carcinoma (SCC) in past decades 3,6-11.

In the South region of Brazil skin cancer rate is higher than for the rest of the country, owing to the rates found in the state of Santa Catarina (SC). The highest concentration of skin cancer is found in this state, with an estimate of 125.78 cases for 100,000 inhabitants for non-melanoma cancer and 8.58 cases for 100,000 inhabitants for melanoma 5.

Malignant skin tumors are divided into two large groups: melanoma and non-melanoma 6,8. The latter include basal cell and squamous cell carcinomas, which all together represent 95% of all skin malignant tumors 8,11. Their isolated incidence is greater than those of lung, colon, breast, rectum carcinomas and lymphomas cases added up 11.

SCC of the skin is the second most common skin malignant neoplasm, amounting to 20% of the cases in the world 12,13.

Histopathology of skin SCC consists of proliferation and differentiation of atypical squamous cells of invasive characteristic 13, which makes it more aggressive than basal cell carcinoma, both locally and in its ability to suffer metastases 13,14.

Only a small amount of primary skin SCC is refractory to standardized dermatological treatment, which consists of complete excision of the tumor. Even though it is easily treated at initial stages and has rare mortality, the consequences of untreated or late diagnosed skin SCC have important impact on public and individual health 1,8,11,12,14,15. The high cost of treatment and deterioration of quality of life as a consequence of psychological and physical sequels confirm the importance of early diagnosis 1.

Even though there are still unknown risk factors for its development, many epidemiological studies have agreed on the significant association between chronic sun exposure and development of this neoplasm 1,3,4,8,12,13,16. Consequently, skin SCC is more common in the elderly, resulting from cumulative sunlight exposure 6,12,16.

Most skin SCC result from actinic keratosis progression 4,13. It is characterized in general by erythematous lesions, which are sometimes brown, of keratotic aspect and with adhered scales. Pain on the lesion site and cell infiltration shown in the histopathology exam predict the greater likelihood of transformation into carcinoma 13.

An additional risk factor for the development of this type of skin cancer is the presence of unfavorable phenotypes 1,13,16, represented by skin types I and II (according to Fitzpatrick classification) 12,13, and light eye color and presence of freckles and nevi 13. In addition to phenotype, two more risk factors are described, which are family history of skin cancer and occupational exposure 3,13. Other risk factors of lesser importance, but also known as carcinogenic, are exposure to tar, arsenic and radiotherapy 1,13.

According to the literature, the incidence of skin squamous cell carcinoma is greater in male ,2,4-10,12,16-18 and it may affect men twice as much as women. These statistics are probably related with occupational activities have sun exposure, normally more predominant in male 3,6. For similar reasons, most skin SCC are found in the head (face and neck) which are areas of greater sun exposure 2,4,7,12-14,17.

As previously mentioned, the state of SC has the highest incidence of skin cancer in Brazil 5, but there are no consistent data in the literature that explain why or whether the incidence has been increasing as for the rest of the country.

The combination of two factors possibly explains this condition: the population of the state is comprised mainly by European descendants, which provides the phenotypic characteristics we have mentioned 1,12, which means they are exposed to greater amount of ultraviolet radiation, resulting from ozone layer deterioration observed in the state 1,12,19.

The high frequency of skin SCC in the country, especially in the state of SC, is an important public health problem in Brazil 1,8,12,14,15. If we had known better about the epidemiology of the neoplasm we could have higher diagnostic suspicion by physicians and other healthcare professionals. Based on the fact that we know the estimated number of skin SCC in the state of SC, but have not determined whether the incidence is increasing or whether the estimate is valid, the present study intended to answer these questions and to define the epidemiological profile of patients with this neoplasm among the inhabitants of the city of Tubarao, in the state of SC.

 

METHODS

An epidemiological observational transversal study was carried out, based on the analysis of pathology results.

We analyzed all positive results for skin SCC diagnosed by pathology analysis in the city of Tubarao (SC) and by systematic randomized selection, within a two year interval between the samples, we selected the years 2000, 2003 and 2006.

We included all pathology analyses with positive results for invasive or in situ SCC, as well as its synonyms such as epidermoid carcinoma, spindle cell, and squamous cells, and the special forms such as Bowen disease and skin verrucous carcinoma, among residents of Tubarao (SC), in the period in which the diagnosis was made. We excluded the results of histological diagnoses different from skin SCC and those in patients who did not live in Tubarao (SC).

The data source was secondary, researched directly from the databases that had results of pathology stored by the computers of Clinical Analysis Laboratories Sao Lucas and DiPrever, which are the only laboratories in the city of Tubarao (SC) that perform this analysis.

The data collection instrument comprised a protocol to record information. Data collection was made between December 2007 and May 2008.

The following variables were assessed: year of anatomical pathologic confirmation, age of patient, gender, greatest diameter of the lesion, and lesion location. The population variable was extracted from the Information Technology Department of Brazilian Universal Healthcare System (DATASUS) 20.

The statistical analysis was made by inputting data into Epidata® 3.1 software, using Epiinfo® 6.04. The calculation of incidence was made using the reference of 100,000 inhabitants/ year, using the number of neoplasms found and population data from DATASUS 20 for the years chosen, as performed in similar studies and for INCA cancer estimates 5,12. The frequency of variables was described in absolute and relative values.

The present study project was submitted for appraisal of the research ethics committee (CEP-UNISUL) and after approval, data collection was made as described above.

 

RESULTS

We found 200 positive reports of skin SCC in the clinical pathology labs of Tubarao (SC). Out of all positive skin reports, 103 (51. 5%) were in female patients.

The incidence for 100,000 inhabitants, according to the year of occurrence, was 94.39 for the year 2006, 71.16 for the year 2003, and 50.86 for the year 2000. There was 40% increase in the risk of acquiring skin SCC comparing the years 2000 and 2003, and 86% increase comparing the years 2000 and 2006. The increasing incidence may be observed in Chart 1.

 

 

Even though in the year 2000 there was greater incidence of skin SCC in female, in years 2003 and 2006 there was increased incidence in male gender. The incidence of skin SCC for 100,000 inhabitants in both genders is shown in Chart 2.

 

 

Ages ranged from 28 to 96 years, mean age of 65. 6 years, median of 67 years and mode of 72 years. The distribution by age range showed more cases among males - 60 cases (66.6%), as among females - 71 cases (71.7%), in patients aged over 60 years (Table 1).

 

 

Table 2 shows the distribution of skin SCC according to lesion location. In both genders, the most common occurrence site was the face - 44 cases, amounting to 57.1% of the 77 reports that provides these data. However, male gender presented 60% higher risk of occurrence of the lesion on the face when compared to female gender.

 

 

Upon analyzing the percentages of skin SCC according to histological subtype found in the study, the most frequent subtypes were in situ and well differentiated, with 164 cases (83%), followed by moderately differentiated, with 29 cases (14.7%) and less frequently, poorly differentiated tumors amounting to only 4 cases (2.0%). Three positive reports for skin SCC did not provide this information.

The greatest diameter of the lesions found in the study ranged from 0.3-10 cm, the mean was 1.9 cm, and the median and the mode were 1.5 cm. Table 3 shows that only 9 (4.57%) of the biopsied lesions had largest diameter ? 4 cm.

 

 

DISCUSSION

There are rare high quality data in the literature about the incidence of SCC, because frequent records of cancer exclude non-melanoma skin cancer or provide incomplete data about their characteristics 8,9,17,21. In recent years, owing to access to electronic databases, skin SCC records confirmed by pathology analysis have been better defined.

By using databases of the laboratories that perform the pathology analyzes in the city of Tubarao (SC), it was possible to include in the present study all recorded cases of skin SCC in the studied years. Therefore, it is likely that the results of this study are closer to the reality than the estimates of incidence used in the city.

The study of positive pathology results for skin SCC in the city of Tubarao (SC) showed increased and growing incidence. Given that there is no specific information by INCA about skin SCC, we used data provided for non-melanoma skin cancer. To enable the comparison between data estimated by INCA and the data found by our study, we had to find out the percentage of non-melanoma skin cancer cases that could be attributed to skin SCC. The literature review showed us that skin SCC is responsible for approximately 20% of all cases of non-melanoma skin cancer 12,13. Based on such information, we estimated the incidence of skin SCC, according to INCA, for the studied years, and then we started the intended comparisons.

The results found by the present study considerably exceeded the incidence expected for the studied years, so as that estimates of skin SCC for year 2006 were 25.16 for 100,000 inhabitants in male and 23.50 for 100,000 inhabitants in female gender, and the ones found in this study were 95.00 and 91. 78 for 100,000 inhabitants in male and female genders, respectively.

Incidences not separated by gender and found in the current study also exceeded the values found in a similar study carried out in Blumenau (SC) in 1980 to 1999. In that study, the authors found a morbidity coefficient of 43.8 for 100,000 inhabitants in the year 1999 12, a lower coefficient but not different from the incidence of 50.86 for 100,000 inhabitants found in the current study in the year 2000. However, when comparing the results of the study with the incidences of years 2003 and 2006, respectively, 71.16 and 94.3 for 100,000 inhabitants, we can see considerable differences. It is important to stress that the study from Blumenau, differently from ours, included in its samples also lip SCC 12.

The incidences found, differently from national data, seemed to be valid when compared to studies carried out in the United States and Australia. In these countries there are high quality incidence rates, even though there is no mandatory reporting system. Incidence data are frequently stratified in studies sponsored by the government and they use population studies and medical charts in addition to clinical pathology confirmation. These countries have recognized that skin cancer became a national public health problem in recent decades.

In Australia, where there is the highest incidence of skin SCC in the world, an increased number of research studies about this neoplasm have been carried out. In a study carried out in the year 2002, the incidence of 387 cases of skin SCC for each 100,000 inhabitants was estimated, as well as the growing increase in its incidence, when analyzing the data recorded since the year 1985 16. In the United States, in the year 1994, there was an incidence of 81 to 136 cases for male and 26 to 59 cases for female gender for 100,000 inhabitants 22. It is likely that the current incidence, following the world trend, is even higher.

The increase in incidence of skin SCC in recent years may be attributed to many different conditions observed in the studied population.

The first and probably the most important one is the increase in ultraviolet radiation resulting from depletion of ozone layer .1,3,6,12,19 It is predicted that for each 10% loss of ozone layer, there is 40% increase in the incidence of skin cancer 23. Thus, small amount depletion may influence the incidence of skin cancer in a considerable proportion.

According to weather data, in the region of SC, there has been reduction of 7 to 8% of the ozone layer per decade from 1979 to 2000 19, inevitably influencing the incidence found in the present study. Moreover, most of the population in the state of SC has fair skin color, resulting from European colonization 1,12. This type of skin is more susceptible to the damage caused by increase in ultraviolet radiation, and is more prone to developing neoplasic lesions when chronically exposed to these rays 1,8,12,16.

The second condition explaining this high incidence is education and awareness of the physicians and especially of the whole population, which might have positively influenced the increase in detection of tumors, which used to be left unnoticed 2,3,8.

In Brazil, skin cancer programs and campaigns started about 10 years ago. The campaigns intend to provide primary prevention - protection against sunlight exposure - and secondary prevention, performing early diagnosis and timely treatment 1.

People over the age of 30 years, responsible for over 50% of the incidence of skin SCC 12,17, are the target of secondary prevention campaigns. Thus, it is plausible to consider that the benefits of these campaigns are reflected inversely on the incidence of population data. It is likely that the improved capacity of physicians and healthcare professionals to track these tumors and the greater awareness of the population are partially responsible for the increase in incidence.

Moreover, there is population aging which occurs in different parts of the world, Brazil included. According to the Brazilian Institute of Geography and Statistics - IBGE, in the year 1991, elderly over 60 years of age represented 6.75% of the population in SC and in the year 2000 they amounted to 8. 03% 24. Cumulative exposure to ultraviolet rays is strongly associated with high incidence of skin SCC, which in comparison to the two other most prevalent skin cancer types, is the most associated with elderly patients 6,12,16, and if there is increase in the elderly population, it is expected to have an increase in the incidence of skin SCC.

Finally, changes in dressing habits and lifestyle, leading to greater sun exposure may also be discussed as an aggravating factor in the increase of skin SCC 1,3,6,8. Another point is the frequent habit of tanning the skin, which is considered esthetically positive in the country 1,3.

2,4-10,12,16-18, with a male: female ratio of 2:1. This fact may be attributed to greater search for medical help by women, as mentioned before, because the records provide values of incidence depending directly on search for medical help. It has been shown by prevention campaigns, among examined records, that the proportion of patients represented by male gender has not achieved 40% 1.It is also important to point out that even though there is not a balance in gender distribution for skin SCC cases in the reviewed literature, there are many studies that showed greater increase in the incidence of skin cancer in female patients, compared to male gender .2,6,18,21.

Owing to the reasons already described above, the highest percentage of skin SCC is found in the population over the age of 60 years .4,12,17 There are other studies that show that the mean age of diagnosis was greater than 65 years 7,10,21. In this study, we found greater number of cases - 131 (69.4%) in patients over the age of 60 years and mean age at diagnosis of 65.6 years, similar to the figures reported by the literature.

The most frequent site for skin SCC in both genders was the head, more specifically the face, in agreement with the literature 2,4,7,12,13,14,17 This finding reinforced the importance of chronic sun exposure as a risk factor, because the face is constantly exposed to sunlight during the day.

Moreover, it was confirmed that men have 60% increased risk of having skin SCC on the face compared to women. One of the reasons that justify this finding is occupational sun exposure, more common among men 3,6. Another hypothesis is the greater concern of female gender for cosmetics and skin care 1,3.

The mean largest diameter of the lesions in the current study was 1.9 cm, similar to other study in which the diameter was 2 cm. In the same study, it was stated that the lesions whose diameters are 4 cm or greater are related with higher potential of tissue invasion 14. Given that in the current study only nine (4.57%) of the found lesions had larger diameters, it is possible to speculate that most lesions caused by skin SCC in the city of Tubarao (SC) have low invasion potential.

 

CONCLUSION

We managed to define a profile for the patients who have skin SCC and the current status of this neoplasm in the population of Tubarao (SC).

1. There was no significant predominance of gender concerning incidence.

2. The highest incidence was found in patients over the age of 60 years.

3. There was significant predominance of lesions on the face.

4. Most lesions - 186 (95.43%) had the largest diameter smaller than 4 cm.

The incidence of skin SCC cases, confirmed by pathology cases, is greater than previously estimated. The distribution of cases showed growing increase in incidence between the years 2000, 2003 and 2006.

Getting to know the increased incidence of this pathology and the profile of the patients that have it enables better planning for Healthcare Education and primary and secondary prevention actions.

 

REFERENCES

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17. Brewster DH, Bhatti LA, Inglis JHC, Nairn ER, Doherty VR. Recent trends in incidence of nonmelanoma skin cancers in the East of Scotland, 1992-2003. Br J Dermatol. 2007;156:1295-300.         [ Links ]

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21. Stang A, Ziegler S, Büchner U, Ziegler B, Jöckel KH, Ziegler V. Malignant melanoma and nonmelanoma skin cancers in Northrhine-Westphalia, Germany: a patient- vs. diagnosis-based incidence approach. Int J Dermatol. 2007;46:564-70         [ Links ]

22. Miller DL, Weinstock MA. Nonmelanoma skin cancer in the United States: incidence. J Am Acad Dermatol. 1994;30:774-8         [ Links ]

23. Oikarinen A, Raitio A. Melanoma and other skin cancer in circumpolar areas. Int J Circumpolar Health. 2000;59:52-6         [ Links ]

24. IBGE – Instituto Brasileiro de Geografia e Estatística – Perfil dos idosos responsáveis pelos domicílios no Brasil 2000. [acesso 20 Jan 2008]. Disponível em: http://www.ibge.gov.br/home/estatistica/populacao/ perfilidoso/tabela1_1.shtm        [ Links ]

 

 

Mailing Address:
Prof. Daniel Holthausen Nunes
Rua Professor Hermínio Jacques, 122
88015 180 Florianópolis SC
Tel.:/FAx: 48 3224-2740
E-mail: daniel@floripa.com.br

 

 

Conflict of interest: None
Financial funding: None
How to cite this article: Nunes DH, Back L, Silva RV, Medeiros VS. Incidência do carcinoma de células escamosas da pele na cidade de Tubarão (SC) – Brasil nos anos de 2000, 2003 e 2006. An Bras Dermatol. 2009;84(5):482-8.