Incidence of thyroid cancer higher in volcanic area of Sicily

Residents living in Sicily’s Catania province, home to the active volcano Mount Etna, were more likely to develop thyroid cancer than those living elsewhere on the island.

Italian researchers conducted a register-based epidemiological survey examining all 1,950 incident thyroid cancers diagnosed in Sicily from January 2002 to December 2004. The age-standardized incidence rate for the world population (ASR_w) was calculated and expressed as the number of thyroid diagnoses per 100,000 residents per year.

The researchers found that the incidence rate for Sicilians living near Mount Etna was high compared with those living in nonvolcanic areas. Women in this region had an ASR_w of 31.7 compared with 14.1 for women in other areas (P<.001). The rate for men in the volcanic area was 6.4 vs. 3.0 for men in the rest of Sicily (P<.001).

Almost 60% of thyroid tumors were 10 mm or smaller. However, the researchers noted that when evaluating cancers larger than 10 mm, Catanians were significantly more likely to have larger cancers. ASR_w for women was 12.3 compared with 6.1 for women in the rest of Sicily. For men, the ASR_w was 2.5 vs. 1.5 for men in the rest of Sicily.

The researchers suspected the differences might be due to environmental factors. Tests of drinking water from Catania showed higher levels of boron, iron, manganese and vanadium than those found in other parts of Sicily, and these levels exceeded maximum permissible concentrations.

Pellegriti G. J Natl Cancer Inst. 2009;101:1575-1583.