I have never heard about these strict restrictions on how to reduce the chance of prostate cancer, and they simply don't make sense.
First it is important to consider that there is correlation with frequent ejaculation with a reduced risk of prostate cancer, but not necessarily causation. The studies that have been completed consider frequent ejaculation to be about 30 times in a month, or roughly once a day. But the studies have not concluded whether ejaculating more often reduced the chance of prostate cancer, or if men who are less likely to get prostate cancer just happen to ejaculate more often.
I'm not a fan of WebMD, but take a look at this:
Masturbation and Prostate Cancer Risk
The main take away from this article is that they don't really know.
Your body normally tells you what you need to do or what you should stop doing. If you feel like having an orgasm then you should probably do that, if you are indifferent to it then you probably don't need to force yourself.
Then again, I don't think anybody gets diagnosed with prostate cancer and starts regretting the orgasms that they had.