Epidemiology of malignant brain tumors in Genova, Italy. 1993-2017

Abstract

We present an updated analysis on the incidence of primary brain tumors in the Metropolitan Area of Genova, the capital of the northwestern Italian region Liguria.The number of cases and incidence rates for all malignant brain tumors, glioblastoma, malignant brain tumors other than glioblastoma, and brain tumors not otherwise specified were calculated for each of seven three-year and one-eighth four-year periods in which the quarter century 1993-2017 was divided. The rates were age-adjusted (AAR) using the 2013 European standard population, presented per 100,000 person-years and the average percentage change over the three-year period was calculated.The number of cases of all malignant brain tumors and glioblastoma was higher in males than in females in each three-year period and in the entire quarter century 1993-2017. During the latter, the average three-year percentage change in AARs for all brain tumors was minimal [0.6 (95% C.I. = -1.0/2.1) %] while for glioblastoma there was a change of 5.3 (95% C.I. = -0.4/11.3) %. The partially concurrent decline in the incidence rates of malignant brain tumors other than glioblastoma or not otherwise specified suggests that the observed increase in the incidence rate of glioblastoma during 1993-2017 may have been at least partially linked to the improvement during the same period in sensitivity and specificity of the diagnosis of glioblastoma, depleting the reservoirs of other malignant or unspecified brain tumors. Research into possibly increased environmental risk factors (e.g., population exposure to ionizing radiation) for glioblastoma in Genova remains warranted.

Keywords: Age-adjusted rate; Brain cancer; Glioblastoma; Glioma; Incidence; Non-otherwise specified.

Fig. 1

Malignant brain tumors in Genova, Italy − 1993–2017. (A) The number of brain malignancies in male (M, left) and female (F, right) in each 3-years – period is shown. Brain malignancies were more common in M vs. F over each 3-year period and the whole 1993–2017 century quarter (two-tailed Mann-Whitney P value < 0.05). (B) The number of GB cases in M (left) and F (right) in each 3-years – period is shown. GB was more common in M vs. F over each 3-year period and the whole 1993–2017 century quarter (two-tailed Mann-Whitney P value < 0.05). (C) Time trend in AARs of all brain malignancies over 1993–2017 by sex. (D) Time trend in AARs of GB over 1993–2017 by sex. (E) Time trend in AARs of brain malignancies other than GB over 1993–2017 by sex. (F) Time trends in AARs of GB, NGB and NOS malignancies in both sexes.