LizP,
The hormone treatment should stop the growth and spread at this stage, by preventing testosterone getting to the cancer cells.
The tablets (probably bicalutamide, but there are others) block the testosterone hormone receptors that enable the cancer to grow. The injection (probably Zoladex, but there are others) stops generation of testosterone, but initially it causes a boost of testosterone (called a flare), and the tablets prevent that boost from getting to the testosterone receptors in the cancer cells. You normally continue with the tablets 1-2 weeks after the first injection, until it has time to start working.
This might be the only treatment that's required for the time being, and you should get plenty of time to consider any other treatment options. Some people are offered chemo early on, but others are not offered chemo unless/until the hormone treatment stops working, which can be many years later.