Doctors implant 100 or so tiny radioactive pellets into the prostate during a short operation.

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An operation to remove the prostate can have serious side-effects, such as loss of control of urinary function, so doctors are unwilling to operate unless the cancer appears life-threatening.

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In a 20-minute procedure, the operation involves pinning open the prostate with four clips to move obstructive tissue out of the way.

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