Note: Laser-cut molybdenum grids for a retarding field energy analyzer.

A retarding field energy analyzer (RFEA) with grids created by laser-cutting a honeycomb mesh in a 50 µm thick molybdenum foil is presented. The flat grids span an area of 1 cm2 and have high transmission (20 µm wide walls between 150 µm wide meshes). The molybdenum grids were tested in a 3-grid RFEA configuration with an analyzer depth of 0.87 mm.

Risk factors for second primary melanoma among Dutch patients with melanoma.

BACKGROUND: Patients with melanoma are at increased risk of developing subsequent primary melanomas. Knowledge about risk factors for these subsequent primaries is scarce. More evidence may help clinicians in tailoring surveillance schedules by selecting patients who could benefit from intensified surveillance. OBJECTIVES: To identify risk factors for a second primary cutaneous melanoma. METHODS: Possible risk factors for a second primary melanoma were assessed in 1127 patients with cutaneous melanoma who were diagnosed between 2003 and 2011 and completed a baseline questionnaire. Additional data were extracted from the Netherlands Cancer Registry and medical files. RESULTS: Fifty-three patients were diagnosed with a second melanoma during a median follow-up time of 6·3 years. The 5-year cumulative risk was 3·7% and the conditional cumulative risk was 4·6% in years 5-10 after diagnosis. In multivariable analyses, the risk of a second melanoma increased with older age at diagnosis [hazard ratio (HR) 1·03 per year; 95% confidence interval (CI) 1·00-1·06], a high naevus density (HR 7·16, 95% CI 2·89-17·75) and working outside for > 10 years (HR 2·88, 95% CI 1·38-6·03). Patients with invasive melanoma (> 1 mm) had a decreased risk compared with patients with melanoma in situ (HR 0·35, 95% CI 0·13-0·93). CONCLUSIONS: Besides phenotypic characteristics, cumulative sun exposure seemed to increase the risk of a second melanoma. Patients with melanoma in situ may need to be offered follow-up, which is currently not advised. As the risk of a second melanoma did not decline in years 5-10 after diagnosis, a subgroup of patients may need a longer follow-up than is currently advised.

Limited role for histopathological examination of re-excision specimens of completely excised melanomas.

The Dutch melanoma guideline advises to examine one central block of the re-excision scar in case of a complete primary excision. To increase the evidence for this recommendation, we re-evaluated how often residual melanoma was found in re-excision specimens of a large series of completely excised melanomas. Of 1,209 Dutch melanoma cases, pathology reports of primary excisions were reviewed. Presence of melanoma in the margins was scored. All melanomas with a complete primary excision were included and pathology reports of re-excisions were reviewed. Presence of residual melanoma in the re-excision specimen and the number of blocks were scored. Slides of re-excision specimens containing residual melanoma were reviewed. Eventually, in four out of 812 melanomas (0.5 %) with a complete primary excision, residual melanoma was found in the re-excision specimen. The free margins of the primary melanomas in these cases ranged from 0.5-3.5 mm. In one case, the margin for melanoma in situ was 0.2 mm. In <1 % of initially completely excised melanomas, residual melanoma was found in the re-excision specimen. Histopathological examination of these re-excision specimens may not be cost-efficient. Our findings even imply that a re-excision could safely be omitted in selected cases of completely excised melanomas.

Impact of mitotic activity on the pathological substaging of pT1 cutaneous melanoma.

BACKGROUND: In the transition from the sixth to the seventh edition of the American Joint Committee on Cancer (AJCC) melanoma staging system, mitotic activity was incorporated, while Clark level of invasion was abandoned. OBJECTIVES: To investigate the effect of this change on the pathological tumour (pT)1 substaging of primary cutaneous melanomas and the possible clinical implications. METHODS: Patients with pT1 melanomas, diagnosed in the period January 2003 to March 2011, were selected from a population-based cohort study on cutaneous melanoma in the eastern part of the Netherlands. The pT1 melanomas were systematically reviewed by an expert pathologist and classified according to both the sixth and the seventh editions of the AJCC staging system. The shift of melanomas between pT1 substages, classified according to the two staging systems, was determined. RESULTS: In total, 260 pT1 melanomas were included. Overall 28% (57/207) of all pT1a melanomas shifted to pT1b when classified according to the new seventh staging classification, because of the presence of mitoses. Some 32% (17/53) of all pT1b melanomas shifted to pT1a. The percentage of pT1b melanomas relative to all pT1 melanomas increased from 20% to 36%. CONCLUSIONS: The addition of mitotic activity to the pathological staging system, according to the seventh edition of the AJCC staging system, resulted in a considerable change in the classification of thin cutaneous melanomas. This shift has clear clinical implications, as it is advised in the Dutch guideline that patients with pT1b melanoma should be offered a sentinel lymph node biopsy.