I'm wondering how much time would you have off work if you had prostate cancer?

Depends on treatment: Hard to be specific since there are several treatment types. It would depend on the choice of treatment and the grade and stage of the cancer. Choices include, surgery, implant of radioactive seeds, external beam radiation, hormone deprivation treatment (drugs). It would also depend on the type of work and physical exertion expected. 1-2 months is a good guess.

Depends on tx: After radioactive seed implant maybe one week at most. Patients tend to work straight through definitive external beam radiation therapy. After surgery they usually take about two weeks off. Antihormonal therapy doesn't usually require any time off.

It depends: Many patients with low risk prostate cancer can undergo active surveillance which doesn't require any treatment and thus no time off work.