The vast majority of men with localized prostate cancer who need active formulation development and treatment, rather than being left to “wait and see’, are treated either with radical prostatectomy or radiation therapy plus anti-androgens. With this treatment, these men do well. However, natural anxieties about the unwanted effects of these treatments have led to the development of alternative treatments with potentially fewer and less severe side effects, and with, it is hoped, the same – or an even better – success rate.
Prostate cancers can be frozen, as well as irradiated. Cryotherapy, or Cryoablation, the use of freezing probes to destroy prostate cancer has a history stretching back to 1964. The system uses hollow tubes inserted into the appropriate parts of the prostate under ultrasound guidance, just as with brachytherapy Liquid nitrogen is then passed along the inside of the tubes, to create an ‘ice ball’ at the end. Early use of Cryotherapy led to promising results, but it was difficult to stop the freeze extending to the rectum and bladder, where it caused considerable and permanent damage in a few patients. Ways of fine-tuning the freezing technique are under study, but it needs far more research before it can be considered a routine treatment.
Laser treatment is a form of Hyperthermia, in that the intense light from a laser is converted into heat when it hits the target tissue. A tube is passed into the urethra to the level of the prostate. It delivers, from its “head’, laser light at right angles to its length under guidance from a fibre-optic tube. The surgeons can see exactly where they are applying the light. The result is ‘coagulation’ (in effect, a burn) of tissue to a depth of 3 to 4 mm. The area removed gradually shrinks into a harmless scar.
The technique has mainly been used several weeks after men have had TURP for localized cancer, to -burn’ away any suspected residual prostate cancer tissue. A 1984 study reported only 7 treatment failures among 63 men two years after their laser surgery. Nine years later another group reported 22 of 26 men as disease-free after TURP followed by laser therapy. However, this was a relatively short follow-up, and none of the men, who all had the initial diagnosis of cancer localized to the prostate, showed the fall in PSA values to near-zero that is needed for reassurance of cure.
New laser techniques are being developed that will surely be used eventually in routine treatment of prostate cancer, but the evidence that lasers are preferable to the tried and trusted treatments for prostate cancer is still sparse. We may have to wait years before we have enough data on it to make a reasoned decision on whether or not it should be used.