Trends in nonmelanoma skin cancer in Japan

The Immune Microenvironment in Basal Cell Carcinoma

The immune system plays a key role in the suppression and progression of basal cell carcinoma (BCC). The primary aetiological factor for BCC development is exposure to ultraviolet radiation (UVR) which, particularly in lighter Fitzpatrick skin types, leads to the accumulation of DNA damage. UVR has roles in the generation of an immunosuppressive environment, facilitating cancer progression. Rates of BCC are elevated in immunosuppressed patients, and BCC may undergo spontaneous immune-mediated regression. Histologic and immunohistochemical profiling of BCCs consistently demonstrates the presence of an immune infiltrate and associated immune proteins. Early studies of immune checkpoint inhibitors reveal promising results in BCC. Therefore, the host immune system and tumor responses to it are important in BCC pathogenesis. Understanding these interactions will be beneficial for disease prognostication and therapeutic decisions.

Melanoma and non-melanoma skin cancer among patients who attended at King Khalid University Hospital in Riyadh, Saudi Arabia from 2007 - 2018

OBJECTIVES

To assess the prevalence of melanoma and non-melanoma skin cancer for patients attended King Khalid University Hospital, Riyadh, Saudi Arabia. We are also assessing the most common category of skin cancer to be encountered among those patients. Methods: The authors conducted a retrospective study including all patients (Saudi and non-Saudi) who attended King Khalid University Hospital (KKUH) at the period of (2007-2018). Data were collected from archives of Pathology Department at KKUH and categorized into: melanoma skin cancer (MSC), non-melanoma skin cancer (NMSC), which included: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), pre-neoplastic lesions, and non-neoplastic skin lesions. Results: A total of 111 patients were reported to have skin cancer out of 9828 cases, which had other skin pathology. Majority of cases were basal cell carcinoma with a total number of 76 (68.5%) of all cases. 18 patients (16.2%) were diagnosed with MSC. The remaining 17 patients (15.3%) were diagnosed with squamous cell carcinoma. Conclusion: Skin cancer prevalence and incidence is increasing worldwide. In our study, BCC was the most common type of skin cancer to be reported in our institute, which is similar to the majority of other international studies.

Diagnosis and Management of Basal Cell Carcinoma

OPINION STATEMENT

Basal cell carcinomas (BCCs) are common skin cancers that tend to appear on sun-exposed skin. Pathobiologically, activation of the Hedgehog signaling pathway characterizes the majority of cases. In general, BCCs are slow-growing and rarely metastasize. Nevertheless, they are locally invasive and can be destructive. While typical cases are diagnosed based on clinical findings, the clinicopathological manifestations are varied. Consequently, skin biopsy is essential to confirm the diagnosis and evaluate the risk of recurrence. In the treatment of primary lesions, the initial goal is to complete tumor removal, whether by conventional surgical excision, Mohs micrographic surgery, cryosurgery, electrodesiccation and curettage, topical application of imiquimod or fluorouracil, photodynamic therapy, or radiation therapy. Of these treatments, surgical excision and Mohs surgery are the most commonly used because of their association with a low recurrence rate and the ability to confirm residual tumor pathologically. However, other treatment options may be preferred according to patient condition, tumor location, and risk of recurrence. In the treatment of metastatic or locally advanced lesions, smoothened inhibitors, which inhibit Hedgehog signaling pathway activation, were recently approved and impressive tumor shrinkage effects have been described. Although the exact prognosis of metastatic BCC has not been analyzed, it is probably poor due to the rarity of such condition. However, emerging molecular targeting agents hold therapeutic promise.

The incidence and body site of skin cancers in the population groups of Astana, Kazakhstan

BACKGROUND AND AIMS

Data on cutaneous malignant melanoma (CMM), squamous cell carcinoma of the skin (SCC), and basal cell carcinoma (BCC) in populations consisting of multi-racial groups in the Commonwealth of Independent States are limited. Here, the main aim was to analyse the incidence and body site of these cancers in the population groups of Astana, Kazakhstan (2007-2016).

METHODS

Annual age standardised incidences and body sites of BCC, SCC, and CMM in Astana's population, divided into "Kazakhs and other Turkic/Asian" and "Russian and other European/Caucasian" groups, were calculated from histologically confirmed cases reported to Astana Oncology Centre.

RESULTS

During the period January 2007 to October 2016, 647 skin cancers were diagnosed. The age and sex standardised incidence of BCC, SCC, and CMM increased significantly between 2007 to 2011 and 2012 to 2016. Higher incidences occurred in the Russian and other European/Caucasian group compared with the Kazakh and other Turkic/Asian group for the 3 skin cancers. BCC was the most common type of skin tumour, followed by SCC, and then CMM, in both population groups and sexes. The head/neck was the commonest site for BCC and SCC in all groups. For CMM, the most frequent site was the trunk in the Russian group and the head/neck in the Kazakh group.

CONCLUSION

The incidence of skin tumours in Astana rose over the past 10 years. Differences in skin phototypes and sun exposure/ protection behaviours may account for the more frequent occurrence of skin tumours in the Russian population group compared with the Kazakh population group.

Prevalence and Clinical Characteristics of Nonmelanoma Skin Cancers Among Hispanic and Asian Patients Compared With White Patients in the United States: A 5-Year, Single-Institution Retrospective Review

BACKGROUND

Nonmelanoma skin cancers (NMSCs) are the most common malignancy in the United States. Although historically most cases occurred in whites, in recent years, NMSC incidence in Hispanics and Asians has increased. As Hispanics and Asians are the 2 fastest growing groups in the United States, the NMSC rise in these populations is concerning. Currently, data on clinical characteristics of NMSCs in these minorities are limited, and a thorough analysis of risk differences among Hispanic, Asian, and white patients is lacking.

OBJECTIVE

To assess differences in NMSC prevalence, risk factors, and clinical presentation among Hispanic, Asian, and white populations at University of California San Diego Dermatologic and Mohs Micrographic Surgery Center.

METHODS

Five-year retrospective chart review.

RESULTS

Of 4,029 NMSC cases, 3,881 (96.3%) were in whites, 115 (2.9%) were in Hispanics, and 33 (0.8%) were in Asians. Most cases in whites occurred in men, whereas this gender ratio was reversed for Hispanics and Asians. Hispanics had significantly more cases occurring in the "central face."

CONCLUSION

The rise of NMSCs in Hispanic and Asians, especially among women, is concerning given that they are the fastest growing ethnic populations in the United States. It is important that proper counseling for photoprotection be stressed to these populations.

Skin Cancer Concerns in People of Color: Risk Factors and Prevention

Background: Though people of color (POC) are less likely to become afflicted with skin cancer, they are much more likely to die from it due to delay in detection or presentation. Very often, skin cancer is diagnosed at a more advanced stage in POC, making treatment difficult.The purpose of this research was to improve awareness regarding skin cancers in people of color by providing recommendations to clinicians and the general public for early detection and photo protection preventive measures. Methods: Data on different types of skin cancers were presented to POC. Due to limited research, there are few resources providing insights for evaluating darkly pigmented lesions in POC. Diagnostic features for different types of skin cancers were recorded and various possible risk factors were considered. Results: This study provided directions for the prevention and early detection of skin cancer in POC based on a comprehensive review of available data. Conclusions: The increased morbidity and mortality rate associated with skin cancer in POC is due to lack of awareness, diagnosis at a more advanced stage and socioeconomic barriers hindering access to care. Raising public health concerns for skin cancer prevention strategies for all people, regardless of ethnic background and socioeconomic status, is the key to timely diagnosis and treatment.

Clinicopathological evaluation of nonmelanoma skin cancer

BACKGROUND

Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), in combination, are referred to as nonmelanoma skin cancers (NMSCs). NMSC is not as extensively studied in the Asian population as it is in the Caucasian population.

AIM

This study sought to evaluate the clinical and histopathologic aspects of NMSC from cases of cutaneous malignancies.

MATERIALS AND METHODS

The present study is a descriptive analysis of NMSC specimens seen at Department of Pathology, SSIMS and RC, Davangere. Histologically diagnosed NMSC, i.e. BCC and SCC specimens from January 2005 to December 2009 were analyzed according to site distribution, risk factors and histological variants.

RESULTS

Of the various specimens received during the 5year study period, 60 were histologically categorized as skin malignancies, of which 31(51.6%) cases were of NMSC. SCC was the most common NMSC constituting 26 (83.9%) cases and 5 NMSC cases (16.1%) were of BCC. The most common incidence was among the age group 60-80 years (80%) for BCC and 40-60 years (50%) for SCC. Head and neck was the most common site of presentation with predilection for face. Forty-six percent of SCC was histologically categorized as well differentiated, 42.3% as moderately differentiated and 11.5% as poorly differentiated. Most common histological variant of BCC was solid (nodular) type.

CONCLUSION

NMSC often associated with greater morbidity, necessitating increased efforts to assess risk factors in individuals, to encourage periodic self-examination and professional evaluation of skin and to optimize strategies for earlier diagnosis and treatment.

A systematic review of worldwide incidence of nonmelanoma skin cancer

BACKGROUND

  Nonmelanoma skin cancer (NMSC) is the most common cancer affecting white-skinned individuals and the incidence is increasing worldwide.

OBJECTIVES

This systematic review brings together 75 studies conducted over the past half century to look at geographical variations and trends worldwide in NMSC, and specifically incidence data are compared with recent U.K. cancer registry data.

METHODS

Following the development of a comprehensive search strategy, an assessment tool was adapted to look at the methodological quality of the eligible studies.

RESULTS

Most of the studies focused on white populations in Europe, the U.S.A. and Australia; however, limited data were available for other skin types in regions such as Africa. Worldwide the incidence for NMSC varies widely with the highest rates in Australia [>1000/100, 000 person-years for basal cell carcinoma (BCC)] and the lowest rates in parts of Africa (< 1/100, 000 person-years for BCC). The average incidence rates in England were 76·21/100, 000 person-years and 22·65/100, 000 person-years for BCC and squamous cell carcinoma (SCC), respectively, with highest rates in the South-West of England (121·29/100, 000 person-years for BCC and 33·02/100, 000 person-years for SCC) and lowest rates by far in London (0·24/100, 000 person-years for BCC and 14·98/100, 000 person-years for SCC). The incidence rates in the U.K. appear to be increasing at a greater rate when compared with the rest of Europe.

CONCLUSIONS

NMSC is an increasing problem for health care services worldwide. This review highlights a requirement for prevention studies in this area and the issues surrounding incomplete NMSC registration. Registration standards of NMSC should be improved to the level of other invasive disease.

Basal cell carcinoma in asians: a retrospective analysis of ten patients

Background. Few studies have been done that characterize basal cell carcinoma (BCC) in Asians because this tumor is relatively uncommon in this population group. Objective. To characterize BCC in Asians. Methods. We retrospectively examined fifteen patient variables and eight tumor variables of ten Asian patients with BCC and compared these results to those of thirty matched Caucasian controls with BCC. Results. Asians developed their first BCC at an older age than the age of first BCC in Caucasian controls (68.9 years versus 58.3 years; P < 0.05). During their lifetime, Asians had fewer BCCs than the number of BCCs in Caucasian controls (1.11 versus 5.41; P < 0.02), despite a similar estimated lifetime daily sun exposure (hours/day) for both groups. Compared to BCCs in Caucasian controls, a higher percentage of BCCs in Asians were clinically pigmented (50.0% versus 3.3%; P < 0.01). Conclusion. Asians develop BCCs later in life and develop fewer BCCs over their lifetime than Caucasians, despite similar estimated lifetime daily sun exposure. This finding is probably due to skin pigmentation in Asians being more protective of ultraviolet light than skin pigmentation in Caucasians.

Unique features of PTCH1 mutation spectrum in Chinese sporadic basal cell carcinoma

BACKGROUND

Alterations of the PTCH1 gene have been found to contribute to both familial and sporadic basal cell carcinoma (BCC), especially in Caucasian patients. Furthermore, the majority of PTCH1 gene mutations in sporadic BCCs in Caucasian patients carry ultraviolet (UV) signatures, suggesting the key role of UV light in BCC development. However, sporadic BCC in non-Caucasian population has a lower incidence, and the pathogenesis remains largely unknown. To date, there has been no mutation analysis on PTCH1 gene in Chinese patients with sporadic BCCs.

OBJECTIVE

To investigate genetic alterations of the PTCH1 gene in Chinese sporadic BCCs.

METHODS

Direct sequencing was used to screen for mutations in PTCH1 in 31 microdissected samples in Chinese sporadic BCCs. In addition, single nucleotide polymorphisms (SNPs) were studied for loss of heterozygosity (LOH).

RESULTS

Nineteen PTCH1 mutations in 17 of the 31 BCCs (54.8%) were identified. SNP analysis revealed LOH of PTCH1 in 10 of 23 BCCs (43.5%). Interestingly, the majority of mutations identified (63.2%) were insertion/deletion, which was different from the results in Caucasian cases whose mutations are predominantly point mutations. Only two (10.5%) of the remaining seven mutations were UV-specific C → T transition or tandem CC → TT transitions. All mutations occurred evenly throughout the entire PTCH1 protein domain without a hot-spot detected.

CONCLUSION

Mutations and LOH in PTCH1 were also highly prevalent in Chinese sporadic BCCs. However, UV light plays a less role in causing these mutations, suggesting other potential mechanisms in the development of sporadic BCC in Chinese patients.

Topography of basal cell carcinoma and their correlations with gender, age and histologic pattern: a retrospective study of 1042 lesions

BACKGROUND

Basal cell carcinoma accounts for 75% of skin cancer. Sun exposure and genetics are related to its etiology. It's expected that biological and behavioral differences provide different patterns of involvement between sexes.

OBJECTIVES

To evaluate the topography of lesions and their correlations with gender, age and histological type.

METHODS

Retrospective study of basal cell carcinoma patients treated between 1999 and 2008 in the Skin Cancer Clinic of Santa Casa de Misericordia of Curitiba. We evaluated sex, age, location, histological type, margins commitment, sun exposure and family skin cancer history.

RESULTS

We found 1042 lesions in 545 patients (61% women), being more numerous in men (p<0.01). Their ages ranged between 27 and 95 years (median=65). Men had more sun exposure (p<0.01). The lesions were more frequent extra-cephalic recently (p<0.01). The margin involvement was higher in the head (p<0.01). The superficial type was less frequent on the head (p<0.01) and was associated with younger ages in women (p<0.01). The head housed 74% of lesions and the legs 2%. Women had a predilection for the legs, nose and upper lip and men to trunk, ears and scalp (p <0.05). The surgeries in the medial epicanthus and scalp occurred at younger ages (p=0.01).

CONCLUSIONS

We identified significant associations between the topography of lesions, gender, age and histological type, demonstrating the possible pathophysiological diversity and differential risk factors operation. In the period studied we found no trend of increase in the proportion of young or women among patients.

Prevalence of precancerous skin lesions and non-melanoma skin cancer in Japanese-Brazilians in Bauru, São Paulo State, Brazil

Precancerous lesions and skin cancer are infrequent in Asians, and have received little documentation in the literature. Brazil has the world's largest contingent of Japanese immigrants and their descendants, and 70% live in the State of São Paulo. The prevalence of such skin lesions in Japanese-Brazilians is unknown. This study aimed to assess the prevalence of actinic keratoses and non-melanoma skin cancer in first and second-generation Japanese-Brazilians over 30 years of age, without miscegenation, living in the city of Bauru, São Paulo State, in 2006. Of the 567 Japanese-Brazilians that underwent dermatological examination, actinic keratosis was diagnosed in 76, with a mean age of 68.9 years, and a single case of basal cell carcinoma was detected in a 39-year-old female patient. In Japan, prevalence of actinic keratosis varies from 0.76% to 5%, and the incidence of non-melanoma skin cancer is 1.2 to 5.4/100 thousand. Japanese-Brazilians from Bauru showed a 13.4% prevalence of actinic keratoses and earlier age at onset. Proximity to the Equator and a history of farming contribute to these higher rates. Presence of solar melanosis was associated with a 1.9-fold risk of developing actinic keratosis.

The Asian dermatologic patient: review of common pigmentary disorders and cutaneous diseases

The Asian patient with Fitzpatrick skin types III-V is rarely highlighted in publications on cutaneous disorders or cutaneous laser surgery. However, with changing demographics, Asians will become an increasingly important group in this context. Although high melanin content confers better photoprotection, photodamage in the form of pigmentary disorders is common. Melasma, freckles, and lentigines are the epidermal disorders commonly seen, whilst nevus of Ota and acquired bilateral nevus of Ota-like macules are common dermal pigmentary disorders. Post-inflammatory hyperpigmentation (PIH) occurring after cutaneous injury remains a hallmark of skin of color. With increasing use of lasers and light sources in Asians, prevention and management of PIH is of great research interest. Bleaching agents, chemical peels, intense pulsed light (IPL) treatments, and fractional skin resurfacing have all been used with some success for the management of melasma. Q-switched (QS) lasers are effective for the management of epidermal pigmentation but are associated with a high risk of PIH. Long-pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers and IPL sources pose less of a PIH risk but require a greater number of treatment sessions. Dermal pigmentary disorders are better targeted by QS ruby, QS alexandrite, and QS 1064-nm Nd:YAG lasers, but hyper- and hypopigmentation may occur. Non-ablative skin rejuvenation using a combination approach with different lasers and light sources in conjunction with cooling devices allows different skin chromophores to be targeted and optimal results to be achieved, even in skin of color. Deep-tissue heating using radiofrequency and infra-red light sources affects the deep dermis and achieves enhanced skin tightening, resulting in eyebrow elevation, rhytide reduction, and contouring of the lower face and jawline. For management of severe degrees of photoaging, fractional resurfacing is useful for wrinkle and pigment reduction, as well as acne scarring. Acne, which is common in Asians, can be treated with topical and oral antibacterials, hormonal treatments, and isotretinoin. Infra-red diode lasers used with a low-fluence, multiple-pass approach have also been shown to be effective with few complications. Fractional skin resurfacing is very useful for improving the appearance of acne scarring. Hypertrophic and keloid scarring, another common condition seen in Asians, can be treated with the combined used of intralesional triamcinolone and fluorouracil, followed by pulsed-dye laser. Esthetic enhancement procedures such as botulinum toxin type A and fillers are becoming increasingly popular. These are effective for rhytide improvement and facial or body contouring. We highlight the differences between Asian skin and other skin types and review conditions common in skin of color together with treatment strategies.

Solid cancer incidence in atomic bomb survivors: 1958-1998

This is the second general report on radiation effects on the incidence of solid cancers (cancers other than malignancies of the blood or blood-forming organs) among members of the Life Span Study (LSS) cohort of Hiroshima and Nagasaki atomic bomb survivors. The analyses were based on 17,448 first primary cancers (including non-melanoma skin cancer) diagnosed from 1958 through 1998 among 105,427 cohort members with individual dose estimates who were alive and not known to have had cancer prior to 1958. Radiation-associated relative risks and excess rates were considered for all solid cancers as a group, for 19 specific cancer sites or groups of sites, and for five histology groups. Poisson regression methods were used to investigate the magnitude of the radiation-associated risks, the shape of the dose response, how these risks vary with gender, age at exposure, and attained age, and the evidence for inter-site variation in the levels and patterns of the excess risk. For all solid cancers as a group, it was estimated that about 850 (about 11%) of the cases among cohort members with colon doses in excess of 0.005 Gy were associated with atomic bomb radiation exposure. The data were consistent with a linear dose response over the 0- to 2-Gy range, while there was some flattening of the dose response at higher doses. Furthermore, there is a statistically significant dose response when analyses were limited to cohort members with doses of 0.15 Gy or less. The excess risks for all solid cancers as a group and many individual sites exhibit significant variation with gender, attained age, and age at exposure. It was estimated that, at age 70 after exposure at age 30, solid cancer rates increase by about 35% per Gy (90% CI 28%; 43%) for men and 58% per Gy (43%; 69%) for women. For all solid cancers as a group, the excess relative risk (ERR per Gy) decreases by about 17% per decade increase in age at exposure (90% CI 7%; 25%) after allowing for attained-age effects, while the ERR decreased in proportion to attained age to the power 1.65 (90% CI 2.1; 1.2) after allowing for age at exposure. Despite the decline in the ERR with attained age, excess absolute rates appeared to increase throughout the study period, providing further evidence that radiation-associated increases in cancer rates persist throughout life regardless of age at exposure. For all solid cancers as a group, women had somewhat higher excess absolute rates than men (F:M ratio 1.4; 90% CI 1.1; 1.8), but this difference disappears when the analysis was restricted to non-gender-specific cancers. Significant radiation-associated increases in risk were seen for most sites, including oral cavity, esophagus, stomach, colon, liver, lung, non-melanoma skin, breast, ovary, bladder, nervous system and thyroid. Although there was no indication of a statistically significant dose response for cancers of the pancreas, prostate and kidney, the excess relative risks for these sites were also consistent with that for all solid cancers as a group. Dose-response estimates for cancers of the rectum, gallbladder and uterus were not statistically significant, and there were suggestions that the risks for these sites may be lower than those for all solid cancers combined. However, there was emerging evidence from the present data that exposure as a child may increase risks of cancer of the body of the uterus. Elevated risks were seen for all of the five broadly classified histological groups considered, including squamous cell carcinoma, adenocarcinoma, other epithelial cancers, sarcomas and other non-epithelial cancers. Although the data were limited, there was a significant radiation-associated increase in the risk of cancer occurring in adolescence and young adulthood. In view of the persisting increase in solid cancer risks, the LSS should continue to provide important new information on radiation exposure and solid cancer risks for at least another 15 to 20 years.

Skin cancer in skin of color

Skin cancer is less common in persons with skin of color than in light-skinned Caucasians but is often associated with greater morbidity and mortality. Thus, it is crucial that physicians become familiar with skin cancer in persons of color so as to maximize the likelihood of early detection of these tumors. In dark-skinned ethnic groups, squamous cell carcinoma is most common; squamous cell carcinoma and melanoma usually occur on nonsun-exposed sites; and ultraviolet radiation is not an important etiologic factor for skin cancer with the exception of basal cell carcinoma. Races of intermediate pigmentation, such as Hispanics and Asians, share epidemiologic and clinical features of dark-skinned ethnic groups and Caucasians. Skin cancers pose a significant risk in skin of color and clinicians should focus on preventive measures in these groups such as regular skin exams, self-examination, public education, and screening programs.

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with the epidemiology and unique clinical features of skin cancer in skin of color and be aware of strategies to prevent skin cancer in skin of color.

Histologic characteristics of skin cancer in Hiroshima and Nagasaki: Background incidence and radiation effects

Skin cancers, though rare in Japan, have reportedly been on the rise, but little else is known about epidemiologic features of different histologic types of skin cancer. The Life Span Study cohort, which consists of 93,700 atomic-bomb survivors, many of whom were exposed to negligibly low radiation doses, and 26,600 people not exposed to radiation, enables a population-based study of spontaneous as well as radiation-related cancer risk. Skin tumor incident cases diagnosed between 1958 and 1987 were ascertained by linkage to the Hiroshima and Nagasaki tumor registries augmented by searches of other data sources. Study pathologists reviewed tumor specimens and pathology reports and classified tumors using the World Health Organization classification scheme. They identified 274 primary incident skin cancers, of which 106 were basal cell carcinoma (BCC), 81 were squamous cell carcinoma (SCC), and 14 were malignant melanomas. Background incidence rates and radiation effects were assessed by Poisson regression models allowing for the effects of demographic and other covariates. BCC and SCC background incidence rates were both about 3 per 100,000 per year. BCCs were mainly on the head/neck (81%), whereas SCCs occurred most frequently on the arms/legs (45%) and head/neck (29%), consistent with the presumed role played by solar UV exposure in skin cancer. The BCC rates increased significantly between 1958 and 1987, whereas the SCC rates remained unchanged. The excess absolute risk of BCC per unit skin surface area related to atomic-bomb radiation exposure did not differ between UV-exposed and shielded parts of the body, suggesting the additivity of the radiation-related and background BCC risks.

Descriptive epidemiology of basal cell carcinoma and cutaneous squamous cell carcinoma in Soria (north-eastern Spain) 1998-2000: a hospital-based survey

INTRODUCTION

Better knowledge of the epidemiology of basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC) will allow the development of more effective diagnostic and preventive measures.

MATERIAL AND METHODS

We have reviewed the clinical records of patients from the 'Hospital General de Soria' who were diagnosed with BCC and/or SCC (lower lip included) by histopathology between 1 January 1998 and 31 December 2000. Recurrences and diagnostic duplicities (tumours first biopsied and then excised) were excluded.

RESULTS

The mean age was 71.4 years for BCC subjects and significantly older, 77.3 years, for SCC subjects. Photoexposed skin areas accounted for 92.6% and 93.8% of BCC and SCC tumours, respectively. The crude incidence rate for the population of 100 000 was 148.27 for BCC and 58.24 for SCC. The age-adjusted incidence rate (adjusted for world standard population) was 57.97 and 17.87 years, respectively. Subjects with superficial BCC were significantly younger than the rest of the BCC patients and their tumours were located on non-photoexposed skin. The ears and dorsum of the hands were the almost exclusive locations of SCC.

CONCLUSIONS

Our results should be compared with those to be obtained in future years to determine trends in the descriptive epidemiology of BCC and SCC.

Screening for skin cancer

CONTEXT

Malignant melanoma is often lethal, and its incidence in the United States has increased rapidly over the past 2 decades. Nonmelanoma skin cancer is seldom lethal, but, if advanced, can cause severe disfigurement and morbidity. Early detection and treatment of melanoma might reduce mortality, while early detection and treatment of nonmelanoma skin cancer might prevent major disfigurement and to a lesser extent prevent mortality. Current recommendations from professional societies regarding screening for skin cancer vary.

OBJECTIVE

To examine published data on the effectiveness of routine screening for skin cancer by a primary care provider, as part of an assessment for the U.S. Preventive Services Task Force.

DATA SOURCES

We searched the MEDLINE database for papers published between 1994 and June 1999, using search terms for screening, physical examination, morbidity, and skin neoplasms. For information on accuracy of screening tests, we used the search terms sensitivity and specificity. We identified the most important studies from before 1994 from the Guide to Clinical Preventive Services, second edition, and from high-quality reviews. We used reference lists and expert recommendations to locate additional articles.

STUDY SELECTION

Two reviewers independently reviewed a subset of 500 abstracts. Once consistency was established, the remainder were reviewed by one reviewer. We included studies if they contained data on yield of screening, screening tests, risk factors, risk assessment, effectiveness of early detection, or cost effectiveness.

DATA EXTRACTION

We abstracted the following descriptive information from full-text published studies of screening and recorded it in an electronic database: type of screening study, study design, setting, population, patient recruitment, screening test description, examiner, advertising targeted at high-risk groups or not targeted, reported risk factors of participants, and procedure for referrals. We also abstracted the yield of screening data including probabilities and numbers of referrals, types of suspected skin cancers, biopsies, confirmed skin cancers, and stages and thickness of skin cancers. For studies that reported test performance, we recorded the definition of a suspicious lesion, the "gold-standard" determination of disease, and the number of true positive, false positive, true negative, and false negative test results. When possible, positive predictive values, likelihood ratios, sensitivity, and specificity were recorded.

DATA SYNTHESIS

No randomized or case-control studies have been done that demonstrate that routine screening for melanoma by primary care providers reduces morbidity or mortality. Basal cell carcinoma and squamous cell carcinoma are very common, but detection and treatment in the absence of formal screening are almost always curative. No controlled studies have shown that formal screening programs will improve this already high cure rate. While the efficacy of screening has not been established, the screening procedures themselves are noninvasive, and the follow-up test, skin biopsy, has low morbidity. Five studies from mass screening programs reported the accuracy of skin examination as a screening test. One of these, a prospective study, tracked patients with negative results to determine the number of patients with false-negative results. In this study, the sensitivity of screening for skin cancer was 94% and specificity was 98%. Several recent case-control studies confirm earlier evidence that risk of melanoma rises with the presence of atypical moles and/or many common moles. One well-done prospective study demonstrated that risk assessment by limited physical exam identified a relatively small (<10%) group of primary care patients for more thorough evaluation.

CONCLUSIONS

The quality of the evidence addressing the accuracy of routine screening by primary care providers for early detection of melanoma or nonmelanoma skin cancer ranged from poor to fair. We found no studies that assessed the effectiveness of periodic skin examination by a clinician in reducing melanoma mortality. Both self-assessment of risk factors or clinician examination can classify a small proportion of patients as at highest risk for melanoma. Skin cancer screening, perhaps using a risk-assessment technique to identify high-risk patients who are seeing a physician for other reasons, merits additional study as a strategy to address the excess burden of disease in older adults.

Factors influencing the linear depth of invasion of primary basal cell carcinoma

BACKGROUND

Predicting subclinical growth of basal cell carcinoma (BCC) is important for clinicians to determine adequate surgical margins. However, few attempts to predict the depth of invasion of BCC prior to surgery have been done.

OBJECTIVE

To identify the factors significantly influencing the depth of invasion of primary BCC.

METHODS

In 235 primary BCCs treated with surgical excision, maximum vertical diameter, designated as "invasion index," from the surrounding skin surface to the bottom of the tumor was measured. Multiple linear regression analysis was used to identify the factors significantly influencing the invasion index. Seven variables including age, sex, duration, anatomic location, tumor horizontal diameter, histologic subtypes, and ulceration were entered into the model.

RESULTS

Among seven variables, male sex (P = 0.0003), larger tumor diameter (P = 0.0011), and histologic subtypes including infiltrative, morpheic, and micronodular subtypes (P = 0.0019) had significant strength of influence for the invasion index.

CONCLUSION

The three predictive factors positively related to the linear depth of invasion in this study are important, but not sufficient, considerations at planning of surgery and for postoperative follow-up of BCC.

Skin phototyping in Asian Australians

Skin phototype was assessed in 257 Asian Australians by self-reporting questionnaire. Minimal erythema dose, minimal melanogenic dose and minimal immediate pigment darkening dose were measured in a subgroup of 50 subjects. About 15% of Asian Australians in this study report that they have skin type I or II. Phototesting confirms that there is a UV-sensitive group and a wide spectrum of UV-sensitivity in this population. Whether Fitzpatrick's skin typing system adequately identifies this UV-sensitive group needs assessment by a larger study. The relationship between burning tendency and tanning capacity in Asians may differ from Caucasians.