There have been incidents in Cairo and Luxor in the recent past, and no indication that's about to change.
In June 2015 there was an attempted terror attack at Luxor (the assailants were killed).
There are regular small explosions in Cairo - usually targeting government buildings, but also metro stations. The explosions are indiscriminate.
Check what your government's travel advice is for Egypt.
You'll have to weigh up for yourself how much risk you're willing to accept.
I'd be asking my tour company about what safety precautions they have in place, and what advice they have for avoiding trouble spots. almost 5 years ago