METHODS
The methodology is described elsewhere (Ferrari et al
201913). Briefly, we included the HDRs nationwide of
all adolescents hospitalized in the years 2002–2015. Among them, we
selected cases with at least one hospital stay for a diagnosis of
cutaneous melanoma (ICD-9-CM diagnostic code = 172* “Malignant melanoma
of skin” and/or ICD-9-CM diagnostic code = V1082 “Personal history of
malignant melanoma of skin”) found in all the six diagnostic fields
(main diagnosis and up to 5 secondary diagnosis) of the HDR. The first
hospitalization indicating a diagnosis of cutaneous melanoma was defined
as the index hospitalization. To select only incident cases, we excluded
patients who were hospitalized during the 5 years or more before their
index hospitalization (i.e. prevalent cases) for the same diagnosis or
for diagnosis referring to cancer or its treatment. The diagnostic
procedures and main treatments for melanoma were established searching
in all the six procedural fields (main procedure and up to 5 secondary
procedures) melanoma-specific ICD-9-CM procedure codes: melanoma
surgical interventions were divided between radical excision (ICD-9-CM
procedure code=86.4 “Radical excision of skin lesion”) and local
excision (ICD-9-CM procedure code=86.3 “Other local excision or
destruction of lesion or tissue of skin and subcutaneous”). We defined
as main treatments those begun within 12 months of the diagnosis. Thus,
study cohort starts in 2007 rather than 2002 and ends in 2014 rather
than 2015. The treatment of each adolescent with melanoma was associated
with only one hospital. When patients were treated at different
hospitals, we assigned them to the hospital performing the radical
excision or, if a radical excision was not performed, we assigned them
to the hospital performing the local excision. Patients without any
hospitalization for neither radical or local excision were assigned to
the hospital where they were diagnosed (this applied to 12% of the
adolescents with melanoma). The hospitals were divided into those having
a unit affiliated to the national pediatric oncology network
Associazione Italiana Ematologia Oncologia Pediatrica (AIEOP) - Italian
Association of Pediatric Hematology and Oncology – and those without it
(non-AIEOP hospitals).
Ethical approval for this study was obtained from the Ethical Commitee
of Fondazione IRCCS Istituto Nazionale dei Tumori (N. INT 132/17).