As an aside, in more recent times the idea of 'cancer clusters' comes up, usually blamed on power lines, mobile phone, nuclear power plants etc.
However this is an old idea that pre-dates these modern devices. People would talk of 'cancer houses'.
From Harmsworth's Universal Encyclopedia: "Cancer:... The death rate in England and Wales 1921 was 1,215 per million of the living... The cause of cancer is unknown. The theory that it is due to a parasite has been the subject of much investigation, but all attempts to isolate and organism.... have failed. This view was held to be supported by the existence of districts in which it is especially prevalent, and still more so by 'cancer houses'.."
Might be obvious but the last lines of the entry say 'Certified by Edmund Wilkinson M.R.C.S. [Member Royal College of Surgeons]'