Rife claimed that his original machines cured cancer. We have no reason at the present time to doubt this claim but it has not been absolutely proven. We don't know exactly how the original machines worked and so the modern machines probably don't work in exactly the same way. Some modern machines have been shown to have been useful in the treatment of some cancer patients but it would be misleading to claim that they represent an absolute cure for cancer.
In general it would be fair to say that Rife type machines have been extremely useful in the control and management of many diseases including many serious ones that haven't responded to conventional treatment but it would be wrong to say that these machines in their present form are a cure for any specific disease.
The Hungarian Company OncoTherm have done several clinical studies in Europe on treating cancer with their Oncotherapy device which uses a Rife frequency modulation. These trials did show a significant improvment in health and a reduction in tumour size.
All serious Rife researchers recommend that you should seek professional medical advice before considering any form of medical treatment with a Rife type machine.