In quanto is a commonly used conjunctive phrase in Italian that translates in numerous ways, including since, as, and because.
Non lo chiamo più in quanto non risponde mai al telefono.
I don’t call him anymore as he never answers the phone.
Less frequently it is followed by che (that) with no change in meaning. For example:
Sono stanco morto in quanto che mio figlio mi ha tenuto sveglio tutta la notte.
I’m exhausted because my son kept me up all night.
You may often see expressions such as ‘in quanto medico‘ or ‘in quanto esperto‘ where in quanto is followed directly by a person’s profession or role. In this case, the only possible translation is as.
Ti parlo in quanto medico e in quanto amico: non prendere quella medicina!
I’m speaking to you as a doctor and as a friend: don’t take that medicine!