Treatment of stage I seminoma, with one course of adjuvant carboplatin or surveillance, risk-adapted recommendations implementing patient autonomy: a report from the Swedish and Norwegian Testicular Cancer Group (SWENOTECA).

BACKGROUND: The purpose of the protocol was to reduce the treatment burden in clinical stage I (CSI) seminoma by offering risk-adapted treatment. The protocol aimed to prospectively validate the proposed risk factors for relapse, stromal invasion of the rete testis and tumor diameter >4 cm, and to evaluate the efficacy of one course of adjuvant carboplatin. PATIENTS AND METHODS: From 2007 to 2010, 897 patients were included in a prospective, population-based, risk-adapted treatment protocol implementing one course of adjuvant carboplatin AUC7 (n = 469) or surveillance (n = 422). In addition, results from 221 patients receiving carboplatin between 2004 and 2007 are reported. RESULTS: At a median follow-up of 5.6 years, 69 relapses have occurred. Stromal invasion of the rete testis [hazard ratio (HR) 1.9, P = 0.011] and tumor diameter >4 cm (HR 2.7, P < 0.001) were identified as risk factors predicting relapse. In patients without risk factors, the relapse rate (RR) was 4.0% for patients managed by surveillance and 2.2% in patients receiving adjuvant carboplatin. In patients with one or two risk factors, the RR was 15.5% in patients managed by surveillance and 9.3% in patients receiving adjuvant carboplatin. We found no increased RR in patients receiving carboplatin <7 × AUC compared with that in patients receiving ≥7 × AUC. CONCLUSION: Stromal invasion in the rete testis and tumor diameter >4 cm are risk factors for relapse in CSI seminoma. Patients without risk factors have a low RR and adjuvant therapy is not justified in these patients. The efficacy of adjuvant carboplatin is relatively low and there is need to explore more effective adjuvant treatment options in patients with high-risk seminoma. The data do not support the concept of a steep dose response for adjuvant carboplatin.

Trends in cutaneous malignant melanoma in Sweden 1997-2011: thinner tumours and improved survival among men.

BACKGROUND: Both patient survival and the proportion of patients diagnosed with thin cutaneous malignant melanoma (CMM) have been steadily rising in Sweden as in most Western countries, although the rate of improvement in survival appears to have declined in Sweden at the end of the last millennium. OBJECTIVES: To analyse the most recent trends in the distribution of tumour thickness (T category) as well as CMM-specific survival in Swedish patients diagnosed during 1997-2011. METHODS: This nationwide population-based study included 30,590 patients registered in the Swedish Melanoma Register (SMR) and diagnosed with a first primary invasive CMM during 1997-2011. The patients were followed through 2012 in the national Cause of Death Register. RESULTS: Logistic and Cox regression analyses adjusting for age at diagnosis, tumour site and healthcare region were carried out. The odds ratio for being diagnosed with thicker tumours was significantly reduced (P < 0·001) and the CMM-specific survival significantly improved in men diagnosed during 2007-2011 compared with men diagnosed during 1997-2001 (hazard ratio = 0·81; 95% confidence interval 0·72-0·91; P < 0·001), while the corresponding differences for women were not significant. Women were diagnosed with significantly thicker tumours during 2002-2006 and a tendency towards decreased survival was observed compared with those diagnosed earlier (during 1997-2001) and later (during 2007-2011). CONCLUSIONS: In Sweden, the CMMs of men are detected earlier over time and this seems to be followed by an improved CMM-specific survival for men. Women are still diagnosed with considerably thinner tumours and they experience a better survival than men.

One course of adjuvant BEP in clinical stage I nonseminoma mature and expanded results from the SWENOTECA group.

BACKGROUND: SWENOTECA has since 1998 offered patients with clinical stage I (CS I) nonseminoma, adjuvant chemotherapy with one course of bleomycin, etoposide and cisplatin (BEP). The aim has been to reduce the risk of relapse, sparing patients the need of toxic salvage treatment. Initial results on 312 patients treated with one course of adjuvant BEP, with a median follow-up of 4.5 years, have been previously published. We now report mature and expanded results. PATIENTS AND METHODS: In a prospective, binational, population-based risk-adapted treatment protocol, 517 Norwegian and Swedish patients with CS I nonseminoma received one course of adjuvant BEP. Patients with lymphovascular invasion (LVI) in the primary testicular tumor were recommended one course of adjuvant BEP. Patients without LVI could choose between surveillance and one course of adjuvant BEP. Data for patients receiving one course of BEP are presented in this study. RESULTS: At a median follow-up of 7.9 years, 12 relapses have occurred, all with IGCCC good prognosis. The latest relapse occurred 3.3 years after adjuvant treatment. The relapse rate at 5 years was 3.2% for patients with LVI and 1.6% for patients without LVI. Five-year cause-specific survival was 100%. CONCLUSIONS: The updated and expanded results confirm a low relapse rate following one course of adjuvant BEP in CS I nonseminoma. One course of adjuvant BEP should be considered a standard treatment in CS I nonseminoma with LVI. For patients with CS I nonseminoma without LVI, one course of adjuvant BEP is also a treatment option.

Prognostic subclassifications of T1 cutaneous melanomas based on ulceration, tumour thickness and Clark's level of invasion: results of a population-based study from the Swedish Melanoma Register.

BACKGROUND: Survival and prognostic factors for thin melanomas have been studied relatively little in population-based settings. This patient group accounts for the majority of melanomas diagnosed in western countries today, and better prognostic information is needed. OBJECTIVES: The aim of this study was to use established prognostic factors such as ulceration, tumour thickness and Clark's level of invasion for risk stratification of T1 cutaneous melanoma. METHODS: From 1990 to 2008, the Swedish Melanoma Register included 97% of all melanomas diagnosed in Sweden. Altogether, 13,026 patients with T1 melanomas in clinical stage I were used for estimating melanoma-specific 10- and 15-year mortality rates. The Cox regression model was used for further survival analysis on 11,165 patients with complete data. RESULTS: Ulceration, tumour thickness and Clark's level of invasion all showed significant, independent, long-term prognostic information. By combining these factors the patients could be subdivided into three risk groups: a low-risk group (67·9% of T1 cases) with a 10-year melanoma-specific mortality rate of 1·5% (1·2-1·9%); an intermediate-risk group (28·6% of T1 cases) with a 10-year mortality rate of 6·1% (5·0-7·3%); and a high-risk group (3·5% of T1 cases) with a 10-year mortality rate of 15·6% (11·2-21·4%). The high- and intermediate-risk groups accounted for 66% of melanoma deaths within T1. CONCLUSIONS: Using a population-based melanoma register, and combining ulceration, tumour thickness and Clark's level of invasion, three distinct prognostic subgroups were identified.

Feelings of loss and uneasiness or shame after removal of a testicle by orchidectomy: a population-based long-term follow-up of testicular cancer survivors.

Few data illustrate the man's reaction to orchidectomy. We investigated long-lasting feelings of loss and uneasiness or shame about the body after removal of a testicle by orchidectomy. We identified 1173 eligible men diagnosed with non-seminomatous testicular cancer treated according to the national cancer-care programmes Swedish-Norwegian Testicular Cancer Group I-IV between 1981 and 2004. We asked the survivors about feelings of loss and uneasiness or shame after having had a testicle removed by orchidectomy. We obtained information from 960 (82%) testicular cancer survivors. We found that 32% of these men miss or previously missed their removed testicle(s) and that 26% have or previously had feelings of uneasiness or shame about their body because of the removed testicle(s). Men who had never been offered a prosthesis reported feelings of loss [relative risk (RR): 2.0; 95% confidence interval (CI): 1.3-3.0] and uneasiness or shame (RR: 2.0; 95% CI: 1.3-3.2) to a higher extent than those who had been offered, but rejected a prosthesis. An orchidectomy may result in long-lasting feelings of loss and uneasiness or shame in some men; offering a testicular prosthesis may hinder this experience.

Long-term follow-up after risk-adapted treatment in clinical stage 1 (CS1) nonseminomatous germ-cell testicular cancer (NSGCT) implementing adjuvant CVB chemotherapy. A SWENOTECA study.

BACKGROUND: To offer minimized risk-adapted adjuvant treatment on a community and nationwide basis for patients with clinical stage 1 (CS1) nonseminomatous germ-cell testicular cancer (NSGCT). The aim was to reduce the risk of relapse and thereby reducing the need of later salvage chemotherapy while maintaining a high cure rate. PATIENTS AND METHODS: From July 1995 to January 1998, a total of 232 Swedish and Norwegian patients were treated for CS1 NSGCT. All were eligible for inclusion into one of two community-based multicenter Swedish and Norwegian Testicular Cancer Project (SWENOTECA) III studies. One study was a prospective randomized study for patients without vascular invasion in the testicular tumor (VASC-), evaluating the effect of one adjuvant course of cisplatin, vinblastine and bleomycin (CVB) compared with surveillance. The second study was a prospective study evaluating the effect of two adjuvant courses of CVB for VASC+ patients. RESULTS: Due to slow accrual and emerging data on toxicity of CVB, the studies were prematurely closed for inclusion in 1998. Of the 232 CS1 patients treated during the study period, only 97 were included in the studies. As all remaining patients were managed according to the SWENOTECA III protocol, although not randomized, the data were pooled. At a median follow-up of 10.1 years, there have been 24 relapses. While one course of CVB to VASC- patients had limited effect on the relapse rate, two courses of adjuvant CVB reduced the relapse rate among VASC+ patients by >90%. Toxicity was high in patients administered adjuvant CVB as 24% of patients experienced grade 3 or 4 obstipation/ileus and 23% grade 3 or 4 infection. CONCLUSIONS: There was no statistical difference in relapse rate between one course of adjuvant CVB and surveillance for VASC- NSGCT patients. Two courses of adjuvant CVB for VASC+ NSGCT patients reduced the relapse rate with >90% in comparison to the surveillance group. Toxicity was unacceptably high for all patients receiving CVB. Adjuvant CVB chemotherapy has no place in the treatment of CS1 NSGCT.

CDKN2A germ-line mutations in individuals with multiple cutaneous melanomas.

Germ-line CDKN2A mutations are present in some kindreds with hereditary cutaneous melanoma, and in Sweden a founder mutation with an extra arginine in codon 113 (113insR) has been identified. We screened 80 individuals with at least two primary cutaneous melanomas, who were identified mainly by a search of a regional cancer registry, for germ-line CDKN2A mutations. In nine patients, CDKN2A alterations that may contribute to melanoma predisposition were detected. In six individuals with a family history of melanoma, the 113insR founder mutation was present. One patient, who also had a family history of melanoma, had a 24-bp deletion that included codons 62-69. An in vitro binding assay established that the resulting mutant p16 protein was unable to bind cyclin-dependent kinase 4 and cyclin-dependent kinase 6. Two patients without a family history of melanoma had CDKN2A alterations: (a) one had a mutation in the 5' noncoding sequence (-14C/T); and (b) the other had an insertion of an extra T in codon 28, which results in a stop signal in codon 43. The median age at diagnosis of the first melanoma was significantly lower, the number of primary melanomas was significantly higher, and the presence of a family history of melanoma was significantly more common in patients with CDKN2A mutations than in those without germ-line mutations. The proportion of CDKN2A mutation carriers was significantly higher among patients treated for three or more primary melanomas compared with those with two tumors only. We conclude that mutation screening of individuals with multiple primary melanomas is a useful strategy to identify new melanoma kindreds with CDKN2A germ-line mutations.

Urinary excretion of 5-S-cysteinyldopa in relation to skin type, UVB-induced erythema, and melanocyte proliferation in human skin.

5-S-Cysteinyldopa (5-S-CD) is found in all pigment-producing cells and is the major precursor of phaeomelanin. However, the melanocyte specificity of the compound has been questioned. In order to elucidate the origin of 5-S-CD, we have now systematically studied the relationship between the 5-S-CD excretion in urine and the size of the melanocyte organ, UV-induced melanocyte proliferation, skin type, and the erythemal reaction. The skin type had no influence on the basal excretion of 5-S-CD. There was no significant correlation between the basal 5-S-CD excretion and the size of the melanocyte organ; that is, the number of skin melanocytes and nevi. During the irradiation, subjects with skin type II developed a more pronounced erythema (p less than 0.01) and had a significantly higher 5-S-CD excretion than those with skin type III-IV (p less than 0.01). No correlation was found between 5-S-CD excretion and UV-induced melanocyte proliferation. The lack of correlation between the basal 5-S-CD excretion and skin type or number of melanocytes suggests that the basal 5-S-CD in urine is mainly of extra-melanocytic origin. Our findings favor the view that the increase in 5-S-CD excretion during UV irradiation is due to UV damage.

UVB irradiation induces melanocyte increase in both exposed and shielded human skin.

This study demonstrates for the first time in humans that UV light induces an increase of the melanocyte population in exposed skin as well as in shielded areas. Because an increased mitotic activity could promote tumor development, UV exposure might play a role in melanoma development not only in exposed but also in covered skin. In addition, it was found that subjects who initially had a small melanocyte population showed a larger increase in both exposed and covered skin compared to those with a high initial density. Individuals with a low density might therefore constitute a risk group for the development of malignant melanoma. These findings support the view that infrequent periods of intensive UV irradiation might be more harmful than regular exposure.

Dacarbazine-vindesine versus dacarbazine-vindesine-cisplatin in disseminated malignant melanoma. A randomised phase III trial.

In a multicentre phase III study of disseminated malignant melanoma performed in Sweden and Norway, 326 patients were randomised to receive treatment with the combination dacarbazine [DTIC] (D) and vindesine (V) with or without the addition of cisplatin (P). D was given intravenously (i.v.) at a dose of 250 mg/m2 days 1-5 every 4 weeks and V was given i.v. at a dose of 3.0 mg/m2 day 1 weekly. P was given i.v. at a dose of 100 mg/m2 day 1 every 4 weeks. There was no statistically significant difference in overall survival between the treatment arms (P = 0.22). Increased toxicity was observed in the treatment arm containing P of which leucopenia, alopecia and nausea/vomiting were the most pronounced. The median time to progression was significantly longer in patients treated with DVP (4.2 versus 2.2 months, P = 0.007). In conclusion, adding P to DV did not change overall survival but did significantly increase toxicity.

Risk-adapted treatment of clinical stage 1 non-seminoma testis cancer.

250 patients with clinical stage 1 non-seminomatous germ cell tumours of the testis (NSGCT 1) were included into a prospective multicentre protocol during 1990-1994 and treated according to three risk strata: patients without tumour cell invasion of vascular structures in the testis (VASC-) and elevated serum AFP levels (AFP+) at orchiectomy were considered low risk (LR) and only observed closely. VASC- and AFP- or VASC+ and AFP+ patients were presumed intermediate risk (IR) and pathologically staged (PS) by retroperitoneal lymph node dissection (RPLND). VASC+ and AFP-patients were regarded as high risk (HR) and received adjuvant chemotherapy (PEB x 3). At a median observation time of 40 (7-68) months, all patients were alive and without evidence of active germ cell cancer. The actuarial relapse rate in the 106 LR patients was 22%, and 70% (14/20) had elevated serum tumour markers at relapse. One of 32 (3%) HR patients relapsed with a resectable retroperitoneal mature teratoma despite adjuvant chemotherapy. Only 14% of the 99 IR patients who underwent RPLND had PS2 disease, and the actuarial relapse rate in 85 PS1 patients was 18%. This multicentre study demonstrated that excellent therapeutic outcome is possible when 18 comparatively small urological and oncological centres follow a strict and formal cancer care programme. The useful prognostic effect of VASC was once again verified. Pathological staging by RPLND in NSGCT1 is, in our opinion, not necessary, with presumed low-risk patients offered surveillance and high-risk patients offered adjuvant chemotherapy.

Characterization of four melanoma cell lines with electron microscopy, immunocytochemistry, cytogenetics, flow cytometry, and southern analysis.

Four cell lines established from human metastatic malignant melanoma, derived from four patients, were analyzed. Ultrastructurally and immunocytochemically, the cultured tumor cells had retained characteristic features of melanocytes and of the primary malignant melanomas. The genetic stability was investigated by repeated flow-cytometric and cytogenetic analyses over 24 months of continuous cultivation. The DNA indices ranged from 1.7 to 2.1 and were stable during the entire period. The same was true for the karyotypes, which had modal numbers ranging from 50 to 84. The most common types of abnormalities were: isochromosomes i(1q), i(9q), translocations (1;17) and (3;6), and other aberrations (1p+,4p+,5p+,11p+,11q-,11q+). Abnormalities involving chromosome 1 were present in all cell lines, but loss of genetic material from chromosome 1p was demonstrated in only one of four cell lines when tested by the Southern blotting technique using a lambda MS1 probe.

Regional distribution of common and dysplastic naevi in relation to melanoma site and sun exposure. A case-control study.

The frequency of melanoma (CMM), and of common and dysplastic naevi (CN and DN) in areas of skin chronically, intermittently and rarely exposed to UV light was investigated in 121 melanoma patients (30-50 years) and 310 controls. Both cases and controls had significantly more CN in intermittently exposed areas than in areas chronically or rarely exposed. The ratio of observed to expected number of CMM was also highest in intermittently exposed skin (1.3 compared to 0.8 in chronically exposed and 0.5 in rarely exposed areas). Thus, intermittent UV exposure seems to have the most potent 'naevogenic' as well as carcinogenic effect on melanocytes. Nineteen per cent of controls and 56% of cases had naevi fulfilling the clinical criteria for DN. The distribution pattern of DN was clearly different from that of CN and does not accord with the idea that UV light is a major aetiological factor for DN. The probability of CMM significantly increased with the degree of relative clustering of CN (p less than 0.05) and of DN (p less than 0.01). This co-variation of naevi and CMM over the body surface might be the result of the local insults to the melanocyte system caused by UV light and/or to the fact that naevi are precursor lesions of CMM.

Sensitivity to extrinsically supplied interferon and the endogenous expression of interferon in melanoma cell lines.

Interferons (IFNs) have been shown to Induce loss of growth potential in melanoma cell lines. However, human melanomas have shown limited responsiveness to clinical therapy with IFN. In a previous study on melanoma cell lines we found that greatest sensitivity to IFN was found in cell lines with the greatest number of copies of chromosome 9p, where the IFN gene family is located. In the present study the expression In melanoma cell lines of IFN genes, IFN receptor genes and standard control genes (beta-actin, glyceraldehyde-3-phosphate dehydrogenase, 18S rRNA and cyclophilin) was investigated using the reverse transcription-polymerase chain reaction, together with an exogenous standard (cyclophllin armoured RNA). We found that the sensitivity to extrinsically supplied IFN seems to correlate with the expression of endogenous IFN genes. The two melanoma cell lines producing the highest relative amount of IFN mRNA transcripts also demonstrated the most marked response to extrinsically supplied IFN. We hypothesize that tumours with enhanced endogenous IFN production may respond more positively to IFN treatment.

Action of interferon alpha and beta on four human melanoma cell lines in vitro.

Four human melanoma cell lines with different copy numbers of chromosomes 9 and 21q, as studied by the G-band technique, fluorescent in situ hybridisation (FISH) and Polymerase chain reaction (PCR), were tested for their sensitivity to Interferon-alpha (IFN-alpha) and Interferon-beta (IFN-beta) in relation to dosage of interferon genes (#9) and interferon receptor genes (#21p). The two most sensitive cell lines were those containing the highest numbers of #9 per cell, while the number of #21q copies (receptor genes) seemed to have no influence on the interferon sensitivity.

Melanocytes, moles and melanoma--a study on UV effects.

To investigate the UV effect on epidermal melanocytes, 21 volunteers and 11 patients with dysplastic nevus syndrome (DNS) received UVB irradiation three times weekly during 17 days. Skin biopsies were taken before and three weeks after the last irradiation (on day 37) from exposed and covered buttock skin. The epidermal melanocyte population density was estimated in dopa-stained split skin preparations. The biopsies taken on day 37 revealed that repeated UVB irradiation induces an increase in the number of melanocytes not only in exposed but also in covered skin. This increased mitotic activity might be a link between sun exposure and melanoma development in covered skin. The size of the proliferative response was inversely correlated to the basal melanocyte number. The larger population increase in skin with few melanocytes might amplify the propagation of DNA damage and increase the likelihood of tumor development. The pigment metabolite 5-S-cysteinyldopa (5-S-CD) was measured in urine before the irradiation and twice weekly until day 38. No correlation was found between the basal 5-S-CD excretion and the size or activity of the melanocyte organ, suggesting that the basal 5-S-CD excretion is mainly of non-melanocytic origin. Despite numerous nevi, DNS-patients did not differ from controls in their 5-S-CD excretion. The normal upper range for the tumor maker 5-S-CD is therefore valid in these melanoma-prone subjects. During the irradiation, subjects with a low tanning ability developed a more pronounced erythema and excreted more 5-S-CD than those with a good tanning ability. This suggests that the UVB-induced 5-S-CD excretion is rather due to melanocyte damage than to an increased melanin synthesis. To investigate the influence of sun exposure on the development of nevi and melanoma (CMM), the distribution over the body surface of CMM, common nevi (CN) greater than or equal to 2 mm and dysplastic nevi (DN) was registered in 121 melanoma patients and 310 controls. Four times as many nevi were found in a sun-exposed area than in a comparable sun-protected area, demonstrating that sun exposure plays an important role in nevus development. Subjects with DNA had a larger difference in nevus counts between the two areas than subjects without DN, indicating a different UV-dose and/or a higher sensitivity to the "nevogenic" effect of UV-light than subjects without DN.(ABSTRACT TRUNCATED AT 400 WORDS)

Low level of education is associated with later stage at diagnosis and reduced survival in cutaneous malignant melanoma: a nationwide population-based study in Sweden.

BACKGROUND: A worse outcome has been reported for cutaneous malignant melanoma (CMM) patients with low socioeconomic status. We have investigated the association between level of education, clinical stage at diagnosis (stage at diagnosis) and CMM-specific survival in Sweden. METHODS: We identified 27,235 patients from the Swedish Melanoma Register diagnosed with a primary invasive CMM between 1990 and 2007 and linked data to nationwide, population-based, health and census registers with a follow-up to 2010. RESULTS: The odds ratio (OR) of higher disease stage at diagnosis was significantly increased in lower education groups (OR stage II versus I=1.6; 95% confidence interval (CI)=1.5-1.7. OR stage III-IV versus I=2.3; 95% CI=1.8-2.9). The risk of dying of CMM, was significantly increased in patients with low (hazard ratio (HR) low versus high=2.02; 95% CI=1.80-2.26; p<0.0001) and intermediate (HR intermediate versus high=1.35; 95% CI=1.20-1.51; p<0.0001) level of education. After adjustment for age, gender, stage at diagnosis and other known prognostic factors, the HRs remained significant for low versus high (HR=1.13; 95% CI=1.01-1.27; p=0.04) but not for intermediate versus high (HR=1.11; 95% CI=0.99-1.24; p=0.08) education. The HR associated with low level of education was significantly higher among female patients, patients <55 years, patients with truncal tumours and during the first 5 years after diagnosis. CONCLUSION: Lower level of education is associated with reduced CMM-specific survival, which may at least partially be attributed to a more advanced stage at diagnosis. These results emphasise the need for improved early detection strategies.

Health-related quality of life in patients with high-risk melanoma randomised in the Nordic phase 3 trial with adjuvant intermediate-dose interferon alfa-2b.

PURPOSE: To compare health-related quality of life (HRQoL) and side-effects in patients with high-risk melanoma participating in a randomised phase III trial of adjuvant interferon alfa-2b (IFN). PATIENTS AND METHODS: A total of 855 patients with histologically verified resected cutaneous melanoma in AJCC stage IIb (T4 N0 M0) or stage III (Tx N1-3 M0) were randomised to: Arm A: observation only (n = 284); Arm B: 1-year treatment: induction: IFN alfa-2b, 10 MU (flat dose), SC, 5 days/week, 4 weeks, maintenance: IFN alfa-2b, 10 MU (flat dose), SC, 3 days/week for 12 months (n = 285); or Arm C: 2 years of same treatment as Arm B. HRQoL was assessed using The European Organisation for Research and Treatment of Cancer Core Questionnaire (EORTC QLQ-C30) before randomisation and at 8 pre-defined time-points during 2 years. IFN-related side-effects were assessed by a study-specific questionnaire. RESULTS: > 80% of eligible patients returned questionnaires at the different assessment points. Statistically significant interactions between randomisation arm and time after randomisation were found for almost all EORTC QLQ-30 variables. While patients in Arm A improved or remained at baseline levels; patients in Arms B and C reported decreased functioning and quality of life, and an increase in side-effects during their treatment. Patients in Arm B improved after the 12th month assessment, when IFN treatment was scheduled to end, to the 16th month assessment (p < 0.001). The same pattern of improvement was found for 5 of 7 interferon-related side-effects. CONCLUSION: A significant negative impact on HRQoL of IFN treatment was demonstrated, however the impact were reversible when treatment was stopped.

Prevalence of common and dysplastic naevi in a Swedish population.

The naevus profile was examined in a Swedish population that was randomly selected from a census file. The participation rate was considered high at 82%. The number of common naevi (CN) and the prevalence of dysplastic naevi (DN) were investigated in 379 subjects (aged 30-50 years). The mean total body count of CN greater than or equal to 2 mm was 67 (range 1-300). As many as 22% of the population had 100 naevi or more and only 18% had less than 25. The counts were not influenced by age or sex. DN were diagnosed clinically in 18% (CI 14-22%) of the subjects and histologically in 8% (CI 5-11%). Subjects with dysplastic naevi had a significantly larger number of common naevi and a more sun-sensitive skin type than subjects without DN, P less than 0.001.

Melanocytic naevi in sun-exposed and protected skin in melanoma patients and controls.

The possible link between exposure to ultraviolet light and naevus development was studied in 121 melanoma patients and 310 controls by comparing the number of naevi in a sun-exposed area on the back with that in a sun-protected area on the buttocks. Both patients and controls had a four-fold increase in the number of naevi in the exposed compared with the protected area, p less than 0.001. The difference in naevus count between the exposed and the protected area was larger in patients than in controls, p less than 0.001. Subjects with dysplastic naevi, melanoma patients as well as controls, had a larger difference in the number of naevi between the two areas than subjects without dysplastic naevi, p less than 0.001. These results support the idea that sunlight plays an important role in naevus development and may explain why a high naevus count is a risk marker for malignant melanoma.