H.S. Rigby

Subungual melanoma: a clinico-pathological study of 24 cases

Twenty-four patients with subungual melanoma (13 women and 11 men) had a mean age of 61.6 years. Twenty-two lesions arose either on the thumb or hallux. The mean delay before diagnosis was 30 months. Two patients presented with stage two melanoma and three of the melanomas were in situ lesions (Clark level 1). Nineteen melanomas were Clark level 4 or 5 and the mean thickness of the invasive melanomas was 4.7 mm. Seven patients died of metastatic disease (mean survival 10 months, range 6-50 months). Clark level, thickness and mitotic activity of the melanomas correlated with poor clinical outcome. Delay in presentation and the presence of advanced disease contribute to the poor prognosis of this tumour.

Recurrence of thin melanoma: how effective is follow-up?

In order to assess the benefit to patients with thin malignant melanoma (< 0.76 mm) of a 5-year clinical follow-up programme, we have studied 602 patients with a minimum time from primary surgery of 5 years. Tumour recurrence occurred in 24 patients (4% of all patients) but only five surgically treatable recurrences (< 1% of all patients) occurred within the 5-year period following primary surgery. After 5 years there were four surgically treatable recurrences, but their prognosis was generally poor. The remaining cases of tumour recurrence were not surgically treatable. In the face of an increasing incidence of melanoma, and the accompanying increase in demand for surgical treatment and outpatient review, we question the need for prolonged hospital follow-up of thin melanoma.

A pigmented lesion clinic : analysis of the first year's 1055 patients

The Pigmented Lesion Clinic (PLC) at Frenchay Hospital was started in January 1993 to deal rapidly and effectively with a growing number of referrals of suspicious pigmented lesions. Its objectives were to offer expert assessment and either reassurance or excision at the first PLC following referral by the patients general practitioner. During 1993, 1055 patients were seen in 37 PLCs and 357 excision biopsies were performed. We have compared the Breslow thicknesses of malignant melanomas diagnosed from the PLCs with those of all other (non-PLC) malignant melanomas referred to our unit over the same period. We discuss the development and results of the first year of our PLC and the advantages it confers.

Sub-lethal effects of exposing the human melanoma cell line Skmel−23 to 532 nm laser light

The human melanoma cell line SKmel‐23 has been used to investigate the sub‐lethal damage that can occur as a result of exposing melanin containing cells to light (532 nm) from a frequency doubled Q‐switched (Nd:YAG) laser. A dose response curve was obtained, which indicates that at energy levels of 0.6 J/cm2 and below no effect on either the viability or growth rate of the cell line was observed. Above this, cells rapidly died and at an energy level of 2.0 J/cm2, only approximately 15% of cells survived. This contrasts with the effects on the G361 melanoma line, which contains far less melanosomes, as an LD50 for this cell line was approximately 5.5 J/cm2. Exposing SKmel‐23 cells to 0.4 J/cm2 of 532 nm light results in a diminution of the number of melanosomes within cells as well as a marked decrease in melanin content, as determined by spectrophotometric assay and electron microscopy. Using the reverse transcriptase polymerase chain reaction technique, the reduction in melanin content of the cells was accompanied by a selective decrease in mRNA coding for tyrosinase, the first enzyme in the biosynthetic pathway for melanin. No decrease in the mRNA coding for the GAPDH protein was observed. Our finding has implications for understanding the control processes that regulate the melanin content of cells and suggests that the model described can be used to further investigate changes that may occur in cells as a result of their exposure to sub‐lethal levels of laser light. Int. J. Cancer 72:1104–1112, 1997.

Follow-up requirements for thick cutaneous melanoma

The primary aim of postoperative melanoma follow-up is the early detection and treatment of treatable recurrences which gives a survival advantage to these patients. The need for follow-up is universally accepted. However, there is ongoing controversy about the duration of follow-up and frequency of reviews. We present a retrospective review of 244 patients with localised thick (> or = 4.0 mm) cutaneous melanoma, who had completed a 10-year follow-up or had died form their melanoma within 10 years. For these criteria, this is the largest series of this type which has been reported to date. The incidence of treatable recurrences peaked in the first postoperative year at 40% and then rapidly decreased, levelling off after year 5 at 2.5% per annum. We believe that this high incidence of treatable recurrences reinforces the need for 10-year follow-up of these patients. We also recommend that the annual frequency of follow-up reviews in each year be based on that years risk for getting a treatable recurrence. Following this principle, we provide an example of such a follow-up programme.

Cutaneous malignant melanoma in the young

Between the years 1967 and 1993, 3246 patients were diagnosed with malignant melanoma at Frenchay Hospital, Bristol. This paper reports 47 patients, 21 years of age or under, including 10 preadolescent cases under 14 years of age. It represents a further follow-up of a cohort originally published from this centre in 1986 in addition to 18 new cases. Most (89%) of the lesions occurred on the trunk and extremities, with females showing a predominance of lesions on the lower limbs. 83% of the melanomas were of the superficial spreading type: 72% invaded to Clark level III and IV. Thickness ranged from 0.29 mm to 50.00 mm (median 1.20 mm). Ulceration was present in 17% of cases and 32% of melanomas arose within a pre-existing small congenital melanocytic naevus. Overall 5-year survival was 81%, with a mean follow-up of 8.5 years. Ulceration and tumour thickness of greater than 1.5 mm were associated with a poor prognosis.

The detection of tyrosinase mRNA in peripheral blood samples is unlikely to aid in the management of patients with localised malignant melanoma

A number of authors have reported the detection of tyrosinase mRNA in the peripheral blood of patients with malignant melanoma using the reverse transcription polymerase chain reaction (RT-PCR). The precise value of this assay as a prognostic tool, however, remains in doubt. This is particularly so with relation to localised disease, where relatively little data has been accumulated. In this study we analysed the peripheral blood of 50 consecutive patients with primary malignant melanoma referred to a plastic surgical centre with the facility of a pigmented lesion clinic. Samples were analysed from an additional 35 patients with advanced melanoma disease and 35 patients with benign pigmented cutaneous lesions. We were able to identify tyrosinase transcripts in the peripheral blood of only two of 50 patients with localised disease. Of those with more advanced disease, a positive finding was found in three with regional disease and four patients with metastatic spread. Stage of disease was found to correlate significantly with PCR status. No correlation was identified with other prognostic markers or with outcome over a three-year period. This data would support the conclusion that the detection of tyrosinase mRNA in peripheral blood is likely to be of little value as an aid in the management of patients with early malignant melanoma.

Cutaneous melanoma : pathological certainties and uncertainties

A historical review is given of the role of histopathology as a prognostic guide to the behaviour of cutaneous melanomas. Problems in the assessment of some of the current parameters are outlined in an attempt to explain the difficulties faced by histopathologists with some types of melanoma.