CLINICAL REPORT
Multiple Primary Melanomas: A Common Occurrence in Western
Sweden
Magdalena CLAESON 1 , Paul HOLMSTRÖM 2 , Stefan HALLBERG 2 , Martin GILLSTEDT 1 , Helena GONZALEZ 1 , Ann-Marie WENNBERG 1
and John PAOLI 1
1
Department of Dermatology and Venereology, Sahlgrenska Academy, and 2 Centre for Health Care Improvement, Chalmers University of
Technology, Gothenburg, Sweden
Patients diagnosed with a single primary cutaneous
melanoma are at increased risk of developing multiple
primary melanomas. The aim of this study is to des-
cribe the epidemiology of multiple primary melanomas
(invasive and in situ) in Western Sweden. Data from
the Swedish Melanoma Registry from 1990 to 2013
revealed that 898 patients (7.4%) developed 2,037
multiple primary lesions and 11,254 patients develo-
ped single lesions. The proportion of subsequent le-
sions that were melanoma in situ was 47%, compared
with 26% of first melanomas (p < 0.0001).The median
and mean time to diagnosis of a subsequent melano-
ma was 38 and 58 months (95% confidence interval
(CI), 53–62 months). In total, 49% of subsequent me-
lanomas were detected within 3 years. Patients and
physicians should be aware of the high proportion of
multiple primary melanomas in Western Sweden, es-
pecially during the first years of follow-up.
Key words: cutaneous malignant melanoma; multiple primary
melanomas; second primary melanoma; synchronous melano-
mas; subsequent melanomas; time to diagnosis.
Accepted Dec 12, 2016; Epub ahead of print Dec 13, 2016
Acta Derm Venereol 2017; 97: 715–719.
Corr: Magdalena Claeson, Department of Dermatology and Venereology,
Sahlgrenska Academy, SE-413 45 Gothenburg, Sweden. E-mail: magda-
[email protected]
715
I
ncidence rates of cutaneous malignant melanoma
(melanoma) are increasing worldwide in the fair-
skinned population (1). Early detection and increased
survival have resulted in a high proportion of melanoma
survivors. It is well known that patients diagnosed with a
single primary melanoma are at elevated risk of develo-
ping multiple primary melanomas during their lifetime.
Multiple lesions can be detected synchronously at a
single visit or during follow-up (i.e. subsequent mela-
nomas). Important risk factors for developing multiple
primary tumours are: age, fair skin type, family history
of melanoma and presence of many or large naevi (2,
3). Research has shown that the percentage of patients
who develop multiple primaries ranges from 0.2% to
8.6% (4, 5). Subsequent melanomas in patients who
attend follow-up have been noted to present with a
thinner Breslow thickness than those who do not attend
follow-up (6, 7). Previous studies have also calculated
the latency of development of subsequent melanomas;
they are most common within the first years after initial
diagnosis (2, 4, 5, 8, 9).
Sweden is among the countries with the highest inci-
dence of melanoma in the world. The incidence increases
annually, by 5.5% for men and 5.2% for women and is
currently 19.5 for men and 20.9 for women/100,000 po-
pulation (World Standard Population year 2000) (10, 11).
The increasing incidence makes melanoma a major health
issue, being the 6 th leading cancer in the country for men
and the 5 th leading cancer for women. Despite increasing
incidence, the national mortality rate has remained low, at
2.8 deaths/100,000 population (World Standard Popula-
tion year 2000) (10). Thus, Sweden has a high proportion
of patients diagnosed with a single primary melanoma at
risk of developing multiple primary melanomas. There are
a few previous studies investigating dif