The response of urological tumours to immunotherapy.

The use of immunotherapy to attempt to treat cancer is not new. At the end of the last century, William Coley observed that the tumour of a patient with a sarcoma who developed streptococcal erysipelas regressed. This led Coley to develop a collection of heat-killed bacteria, known as Coley's toxins, which he used to activate the immune system, with some reported tumour regressions. Subsequently, several investigators used BCG to treat solid tumours. When used by intralesional injection, BCG induced regressions of melanoma skin metastases in some patients, but without affecting survival. In 1976, Morales described the use of intravesical BCG to treat superficial transitional cell carcinoma (TCC) of the bladder. The efficacy of intravesical BCG remains the most successful example of cancer immunotherapy to date.