The 5 year thing sounds right - there is a risk of getting breast cancer again if she gets pregnant during that time. I googled it and found an article that said pregnancy should be avoided for 3-4 years. This is because breast cancer is fuelled by hormones and of course during pregnancy you have huge surges of them and therefore would be more likely to see a reccurance of the cancer. From 5 years on apparently the risk factors are the same as a woman who hasn't had cancer.

As for chemo & radiation - my mum's been through both twice for breast cancer (and had both BBs removed) and she sailed through it all. I think her positive attitude helped. She got really bad burns with the radiation (some came up several months after treatment) and she found that the worst of it. She really didn't find it all that bad, so everyone's experience seems to be different.