Risk of Second Cancers in Merkel Cell Carcinoma: A Meta-Analysis of Population Based Cohort Studies

Table 1

Characteristics of studies included in the meta-analysis.

Study, year	Country	Data source, study period	Number of cases of MCC	Age at diagnosis; ( or median)	Mean follow-up	Number of second malignancies	All malignancies SIR (95% CI)	Number solid of cancers
Brenner et al., 2001 [24]	Israel	ICR; 1983–1999	M—35; F—32	<50 yrs.—5; 50–59 yrs.—10; 60–69 yrs.—11; 70–79 yrs.—29; >80 yrs.—12	3.6 years	5 (total)	2.8; (1.38–4.22)	12 (NA)
Howard et al., 2006 [25]	USA	SEER; 1986–2002	M—756; F—560	<60 yrs.—172; 60–69 yrs.—246; >70 yrs.—888	3.5 years	83 (after 1 yr.); 122 (total)	1.07; (0.85–1.33)	71 (after 1 yr.); 101 (total)
Koljonen et al., 2010 [26]	Finland	FCR; 1979–2006	M—53; F—119	<29 yrs.—1; 30–44 yrs.—3; 45–59 yrs.—14; 60–74 yrs.—50; >75 yrs.—104	4.1 years	1 (with MCC); 33 (after ≥1 m); 34 (total)	1.69; (0.85–3.03)	30 (NA)
Bzhalava et al., 2011 [27]	Denmark; Norway; Sweden	NCR; 1980–2007; 1990–2007; 1990–2007	M—314; F—442	<29 yrs.—2; 30–44 yrs.—8; 45–59 yrs.—35; 60–74 yrs.—181; >75 yrs.—530	3.5 years	79 (after 6 m); 65 (after 1 yr.); 142 (total)	1.13; (0.89–1.44)	75 (after 6 m); 63 (after 1 yr.)
Youlden et al., 2014 [28]	Australia	QCR; 1982–2010	M—512; F—275	75 (29–104)	2.2 years (median)	135 (after 2 m); 105 (after 1 yr.); 240 (total)	1.87; (1.53–2.26)	85 (after 2 m); 63 (after 1 yr.); 148 (total)

NCR: National Cancer Registries; SEER: Surveillance, Epidemiology, and End Results; FCR: Finnish Cancer Registry; NIS: National Institute of Statistics; ICR: Israel Cancer Registry; QCR: Queensland Cancer Registry. SIR: standardized incidence ratio; CI: confidence interval.