Immunotherapy includes techniques to boost natural immune
resistance to tumours with both vaccines and biologic
response modifiers, primarily cytokines involved in modulating
immune responses. The occasional dramatic disappearance
of widespread metastases is probably attributable,
in most cases, to a brisk and successful immunologic
response. The occasional patient who survives in the face
of known metastatic disease for a decade or more is probably
also a testament to an effective immunologic host response.
These occasional examples demonstrate the power
of the immune system to arrest or even cure what appears
to be a hopeless case. Clearly, we would like to be able to
achieve this result deliberately in all cancer victims. The
key to achieving predictable and significant immune responses
in cancer patients lies in a better understanding of
the nature of tumour immunity.