Cancer is a common disease in adults. Rates in different sub-populations vary for many reasons, including internal risk factors of the members of the group, exposure to external carcinogenic risk factors and random variation. Higher (and lower) rates (i.e. clustering) due to random variation is expected. However, not surprisingly, this can cause concern amongst people within the affected population that there is a “cause” for this apparent clustering that should be identified and prevented. The workplace is a common place for such concerns to arise.

Problem carcinogenic exposures should of course be identified and controlled in any situation, but commonly concerns arise in workplaces where it is very unlikely carcinogenic exposures are, or have ever been, present. Nevertheless, the concerns of workers are real and should be taken seriously. In many instances where significant cancer cluster worries have arisen in a work setting, there has been a perception amongst workers that management have been slow to react to workers’ concerns or did not investigate their concerns appropriately. This is commonly because management was unsure of how to approach the issue rather than being due to a lack of care.

Concerns about the possible presence of a “cluster” should never be dismissed. The required response can vary from a few discussions to a full-scale epidemiological investigation. A useful initial approach is to respond early, get external advice from someone experienced in cluster investigations and give all interested parties an opportunity to have their concerns known and considered. If more than a minor consideration is needed then the next steps can usefully include establishing a reference group; focusing on exposures and case characteristics rather than on cancer rates; and regular communication with all interested parties.