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Squamous cell carcinoma: Could it be the most common skin cancer?

1998; Elsevier BV; Volume: 39; Issue: 1 Linguagem: Inglês

10.1016/s0190-9622(98)70419-0

1097-6787

B. Cohn,

Cancer and Skin Lesions

To the Editor:Dogma, which seems to be based only on histopathologic data, declares that basal cell carcinoma is the most common skin cancer, having more than three times the incidence of squamous cell carcinoma. Is this true?In a review of nonmelanoma skin cancers, it was stated regarding some incidence figures from the United States that, because they were based on pathologically confirmed diagnoses and excluded untreated lesions or lesions treated without biopsy, they were conservative estimates.1Preston DS Stern RS Nonmelanoma cancers of the skin.N Engl J Med. 1992; 327: 1649-1662Crossref PubMed Scopus (448) Google Scholar The Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, which collects cancer incidence and survival data, does not collect these data for basal cell carcinoma or squamous cell carcinoma of the skin, other than those of the genitalia. In California, the law that requires cancer diagnoses to be reported excludes these same skin cancers, with the exception again of those of the genitalia. In Australia, where the surveys for these skin cancers have been the most extensive, it has been stated that nonmelanoma skin cancers are difficult to monitor with conventional cancer-registration procedures because many are treated with destructive techniques that preclude histologic confirmation.2Marks R Staples M Giles GG Trends in non-melanocytic skin cancer treated in Australia: the second national survey.Int J Cancer. 1993; 53: 585-590Crossref PubMed Scopus (220) Google ScholarIn the American Academy of Dermatology statement on actinic keratoses (J Am Acad Dermatol 1997;36:650-3) Callen, Bickers, and Moy state that, although it is usually possible to diagnose actinic keratosis on the basis of its clinical appearance, it may be difficult (or impossible) to distinguish one from a squamous cell carcinoma of the skin and other pathologic lesions without a skin biopsy.In a current textbook it is stated that the differences between squamous cell carcinoma and actinic keratosis lie in the degree rather than the type of changes and that no sharp line of demarcation exists between the two. Not infrequently, on step sectioning, an actinic keratosis reveals one or several areas in which the changes have progressed to squamous cell carcinoma.3Kirkham N Tumors and cysts of the epidermis.in: 8th ed. Lever’s Histopathology of the skin. Lippincott-Raven, Philadelphia1997: 685-746Google ScholarIn their study on 42 white persons with severe actinic damage (J Am Acad Dermatol 1997;37:392-4), Suchniak, Baer, and Goldberg found that 50 clinically diagnosed papular hyperkeratotic actinic keratoses less than 1 cm in diameter were not uniform histopathologically, with 18 of these lesions (36%) being invasive squamous cell carcinomas.Estimates of the conversion rate for an actinic keratosis to a squamous cell carcinoma have varied greatly.4Dodson JM DeSpain J Hewett JE Clark DP Malignant potential of actinic keratoses and the controversy over treatment: a patient-oriented perspective.Arch Dermatol. 1991; 127: 1029-1031Crossref PubMed Scopus (212) Google Scholar, 5Marks R The role of treatment of actinic keratoses in the prevention of morbidity and mortality due to squamous cell carcinoma.Arch Dermatol. 1991; 127: 131-133Crossref Scopus (43) Google Scholar In a study of 1689 persons during a 5-year period, which was designed to determine the incidence of this transformation, it was stated that all diagnoses of squamous cell carcinoma were proved by biopsy findings, but it was also acknowledged that most diagnoses of solar keratoses were clinical.6Marks R Rennie G Selwood TS Malignant transformation of solar keratoses to squamous cell carcinoma.Lancet. 1988; 1: 795-797Abstract PubMed Scopus (520) Google Scholar The possibility of some errors in the clinical diagnoses was mentioned. Because the borderline between actinic keratosis and squamous cell carcinoma is indistinct, it seems that the determination of the incidence of this transformation is problematic. In contrast, basal cell carcinoma does not present with the same conceptual problem because it does not have a precursor lesion.The number of actinic keratoses in some persons with severe solar damage can be countless. The common widespread reaction to topical 5-fluorouracil treatment attests to the numerous actinic keratoses that can be present. Although histopathologic evaluation is routinely done on clinically diagnosed basal cell carcinoma and squamous cell carcinoma, this examination is a practical consideration for only some, but not for most, actinic keratoses. It is likely that some early squamous cell carcinomas are being treated with cryotherapy and other techniques as solar keratoses without the benefit of histologic examination to rule out invasive changes. 7Marks R Jolley D Dorevitch AP Selwood TS The incidence of non-melanocytic skin cancers in an Australian population: results of a five-year prospective study.Med J Aust. 1989; 150: 475-478PubMed Google Scholar If the aforementioned study on the 50 hyperkeratotic lesions is representative, it might suggest that the incidence of squamous cell carcinoma of the skin could be significantly greater than what has been generally thought.More than a century ago Dubreuilh 8Dubreuilh W Des hyperkeratoses circonscrites.in: Third international congress of dermatology - official transactions. Waterlow and Sons, London1898: 125-176Google Scholar presented his concept that there are keratoses that are precancerous. Could it be that squamous cell carcinoma, which on occasion can develop from a keratosis, is the most common skin cancer? To the Editor:Dogma, which seems to be based only on histopathologic data, declares that basal cell carcinoma is the most common skin cancer, having more than three times the incidence of squamous cell carcinoma. Is this true?In a review of nonmelanoma skin cancers, it was stated regarding some incidence figures from the United States that, because they were based on pathologically confirmed diagnoses and excluded untreated lesions or lesions treated without biopsy, they were conservative estimates.1Preston DS Stern RS Nonmelanoma cancers of the skin.N Engl J Med. 1992; 327: 1649-1662Crossref PubMed Scopus (448) Google Scholar The Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, which collects cancer incidence and survival data, does not collect these data for basal cell carcinoma or squamous cell carcinoma of the skin, other than those of the genitalia. In California, the law that requires cancer diagnoses to be reported excludes these same skin cancers, with the exception again of those of the genitalia. In Australia, where the surveys for these skin cancers have been the most extensive, it has been stated that nonmelanoma skin cancers are difficult to monitor with conventional cancer-registration procedures because many are treated with destructive techniques that preclude histologic confirmation.2Marks R Staples M Giles GG Trends in non-melanocytic skin cancer treated in Australia: the second national survey.Int J Cancer. 1993; 53: 585-590Crossref PubMed Scopus (220) Google ScholarIn the American Academy of Dermatology statement on actinic keratoses (J Am Acad Dermatol 1997;36:650-3) Callen, Bickers, and Moy state that, although it is usually possible to diagnose actinic keratosis on the basis of its clinical appearance, it may be difficult (or impossible) to distinguish one from a squamous cell carcinoma of the skin and other pathologic lesions without a skin biopsy.In a current textbook it is stated that the differences between squamous cell carcinoma and actinic keratosis lie in the degree rather than the type of changes and that no sharp line of demarcation exists between the two. Not infrequently, on step sectioning, an actinic keratosis reveals one or several areas in which the changes have progressed to squamous cell carcinoma.3Kirkham N Tumors and cysts of the epidermis.in: 8th ed. Lever’s Histopathology of the skin. Lippincott-Raven, Philadelphia1997: 685-746Google ScholarIn their study on 42 white persons with severe actinic damage (J Am Acad Dermatol 1997;37:392-4), Suchniak, Baer, and Goldberg found that 50 clinically diagnosed papular hyperkeratotic actinic keratoses less than 1 cm in diameter were not uniform histopathologically, with 18 of these lesions (36%) being invasive squamous cell carcinomas.Estimates of the conversion rate for an actinic keratosis to a squamous cell carcinoma have varied greatly.4Dodson JM DeSpain J Hewett JE Clark DP Malignant potential of actinic keratoses and the controversy over treatment: a patient-oriented perspective.Arch Dermatol. 1991; 127: 1029-1031Crossref PubMed Scopus (212) Google Scholar, 5Marks R The role of treatment of actinic keratoses in the prevention of morbidity and mortality due to squamous cell carcinoma.Arch Dermatol. 1991; 127: 131-133Crossref Scopus (43) Google Scholar In a study of 1689 persons during a 5-year period, which was designed to determine the incidence of this transformation, it was stated that all diagnoses of squamous cell carcinoma were proved by biopsy findings, but it was also acknowledged that most diagnoses of solar keratoses were clinical.6Marks R Rennie G Selwood TS Malignant transformation of solar keratoses to squamous cell carcinoma.Lancet. 1988; 1: 795-797Abstract PubMed Scopus (520) Google Scholar The possibility of some errors in the clinical diagnoses was mentioned. Because the borderline between actinic keratosis and squamous cell carcinoma is indistinct, it seems that the determination of the incidence of this transformation is problematic. In contrast, basal cell carcinoma does not present with the same conceptual problem because it does not have a precursor lesion.The number of actinic keratoses in some persons with severe solar damage can be countless. The common widespread reaction to topical 5-fluorouracil treatment attests to the numerous actinic keratoses that can be present. Although histopathologic evaluation is routinely done on clinically diagnosed basal cell carcinoma and squamous cell carcinoma, this examination is a practical consideration for only some, but not for most, actinic keratoses. It is likely that some early squamous cell carcinomas are being treated with cryotherapy and other techniques as solar keratoses without the benefit of histologic examination to rule out invasive changes. 7Marks R Jolley D Dorevitch AP Selwood TS The incidence of non-melanocytic skin cancers in an Australian population: results of a five-year prospective study.Med J Aust. 1989; 150: 475-478PubMed Google Scholar If the aforementioned study on the 50 hyperkeratotic lesions is representative, it might suggest that the incidence of squamous cell carcinoma of the skin could be significantly greater than what has been generally thought.More than a century ago Dubreuilh 8Dubreuilh W Des hyperkeratoses circonscrites.in: Third international congress of dermatology - official transactions. Waterlow and Sons, London1898: 125-176Google Scholar presented his concept that there are keratoses that are precancerous. Could it be that squamous cell carcinoma, which on occasion can develop from a keratosis, is the most common skin cancer? Dogma, which seems to be based only on histopathologic data, declares that basal cell carcinoma is the most common skin cancer, having more than three times the incidence of squamous cell carcinoma. Is this true? In a review of nonmelanoma skin cancers, it was stated regarding some incidence figures from the United States that, because they were based on pathologically confirmed diagnoses and excluded untreated lesions or lesions treated without biopsy, they were conservative estimates.1Preston DS Stern RS Nonmelanoma cancers of the skin.N Engl J Med. 1992; 327: 1649-1662Crossref PubMed Scopus (448) Google Scholar The Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, which collects cancer incidence and survival data, does not collect these data for basal cell carcinoma or squamous cell carcinoma of the skin, other than those of the genitalia. In California, the law that requires cancer diagnoses to be reported excludes these same skin cancers, with the exception again of those of the genitalia. In Australia, where the surveys for these skin cancers have been the most extensive, it has been stated that nonmelanoma skin cancers are difficult to monitor with conventional cancer-registration procedures because many are treated with destructive techniques that preclude histologic confirmation.2Marks R Staples M Giles GG Trends in non-melanocytic skin cancer treated in Australia: the second national survey.Int J Cancer. 1993; 53: 585-590Crossref PubMed Scopus (220) Google Scholar In the American Academy of Dermatology statement on actinic keratoses (J Am Acad Dermatol 1997;36:650-3) Callen, Bickers, and Moy state that, although it is usually possible to diagnose actinic keratosis on the basis of its clinical appearance, it may be difficult (or impossible) to distinguish one from a squamous cell carcinoma of the skin and other pathologic lesions without a skin biopsy. In a current textbook it is stated that the differences between squamous cell carcinoma and actinic keratosis lie in the degree rather than the type of changes and that no sharp line of demarcation exists between the two. Not infrequently, on step sectioning, an actinic keratosis reveals one or several areas in which the changes have progressed to squamous cell carcinoma.3Kirkham N Tumors and cysts of the epidermis.in: 8th ed. Lever’s Histopathology of the skin. Lippincott-Raven, Philadelphia1997: 685-746Google Scholar In their study on 42 white persons with severe actinic damage (J Am Acad Dermatol 1997;37:392-4), Suchniak, Baer, and Goldberg found that 50 clinically diagnosed papular hyperkeratotic actinic keratoses less than 1 cm in diameter were not uniform histopathologically, with 18 of these lesions (36%) being invasive squamous cell carcinomas. Estimates of the conversion rate for an actinic keratosis to a squamous cell carcinoma have varied greatly.4Dodson JM DeSpain J Hewett JE Clark DP Malignant potential of actinic keratoses and the controversy over treatment: a patient-oriented perspective.Arch Dermatol. 1991; 127: 1029-1031Crossref PubMed Scopus (212) Google Scholar, 5Marks R The role of treatment of actinic keratoses in the prevention of morbidity and mortality due to squamous cell carcinoma.Arch Dermatol. 1991; 127: 131-133Crossref Scopus (43) Google Scholar In a study of 1689 persons during a 5-year period, which was designed to determine the incidence of this transformation, it was stated that all diagnoses of squamous cell carcinoma were proved by biopsy findings, but it was also acknowledged that most diagnoses of solar keratoses were clinical.6Marks R Rennie G Selwood TS Malignant transformation of solar keratoses to squamous cell carcinoma.Lancet. 1988; 1: 795-797Abstract PubMed Scopus (520) Google Scholar The possibility of some errors in the clinical diagnoses was mentioned. Because the borderline between actinic keratosis and squamous cell carcinoma is indistinct, it seems that the determination of the incidence of this transformation is problematic. In contrast, basal cell carcinoma does not present with the same conceptual problem because it does not have a precursor lesion. The number of actinic keratoses in some persons with severe solar damage can be countless. The common widespread reaction to topical 5-fluorouracil treatment attests to the numerous actinic keratoses that can be present. Although histopathologic evaluation is routinely done on clinically diagnosed basal cell carcinoma and squamous cell carcinoma, this examination is a practical consideration for only some, but not for most, actinic keratoses. It is likely that some early squamous cell carcinomas are being treated with cryotherapy and other techniques as solar keratoses without the benefit of histologic examination to rule out invasive changes. 7Marks R Jolley D Dorevitch AP Selwood TS The incidence of non-melanocytic skin cancers in an Australian population: results of a five-year prospective study.Med J Aust. 1989; 150: 475-478PubMed Google Scholar If the aforementioned study on the 50 hyperkeratotic lesions is representative, it might suggest that the incidence of squamous cell carcinoma of the skin could be significantly greater than what has been generally thought. More than a century ago Dubreuilh 8Dubreuilh W Des hyperkeratoses circonscrites.in: Third international congress of dermatology - official transactions. Waterlow and Sons, London1898: 125-176Google Scholar presented his concept that there are keratoses that are precancerous. Could it be that squamous cell carcinoma, which on occasion can develop from a keratosis, is the most common skin cancer?