URINARY BLADDER CANCER IN A FORMER AREA OF UNDERGROUND HARD COAL MINING

Urinary bladder cancer in miners is currently under debate. We report on a recently performed study on 196 bladder cancer cases (80% males) from Dortmund, a centre of the former underground hard coal mining in Germany, and 240 controls (77% males) with benign urological diseases and without a history of malignancies, assessed by questionnaire from July 2009 to December 2010.

Results: Twenty bladder cancer cases (10%) and 8 controls (3%) had an occupational history of hard coal mining (OR 3.22, 95% CI 1.39 - 7.49; brown coal mining: 2 cases, no control). In general, the working time as a hard coal miner was less than 20 yr, mostly in the late 1940s or in the 1950s.

Discussion: These findings are in line with an earlier study in this area on 412 male bladder cancer patients and 414 controls with benign prostatic hyperplasia investigated from 1984 to 1988 presenting a smoking-adjusted odds ratio for bladder cancer of 2.54 (95% CI 1.64 - 3.93) (Golka et al., 1998) and a meta-analysis presented at the WHO International Consultation on Bladder Cancer describing a significantly increased summary related risk (SRR) of 1.31 (95% CI 1.09 - 1.58) which was the highest one reported for all occupations investigated (Reulen et al., 2008). Aromatic amines the most notorious bladder carcinogens in humans are not a constituent of hard coal. Furthermore, the slow N-acetyltransferase 2 status, which is associated with an increased bladder cancer risk in persons formerly exposed to aromatic amines, was normal in hard coal miners with bladder cancer in both studies in the Dortmund area.

Conclusion: The results of the two studies in the Dortmund area indicate that the increased bladder cancer risk in underground hard coal miners cannot be caused by the exposure to carcinogenic aromatic amines.