"largely treated" is a correct and usable phrase in written English.
It means that something has been treated to a large extent or mostly. Example: The issue of poverty was largely treated in the government's new policy proposals, but some critics argue that more needs to be done to address the root causes.
Indeed, due to its anatomical proximity to large bowel and the presence of some clinico-pathological commonalities with colorectal cancer (CRC), SBA is often assimilated to the adenocarcinoma arising from the large bowel and largely treated according to the management recommendations for CRC.
For decades the medical profession has largely treated addiction as as a chronic brain disease.
Statistical process control and maintenance optimization have an intuitive relationship, but the literature has largely treated them as separate entities.
In policy-making, reducing energy consumption from lighting is largely treated as a matter of optimizing products.
Many say that the C.D.C. has largely treated their disease as a psychological or stress-related condition.
The spectacle, mixing politics, money, high drama and the law, has riveted the Pakistani media, which had largely treated the chief justice with deference bordering on reverence.
But they largely treat the trials as a domestic affair that is not their concern.
Male university graduates largely treat their wives as equals; less educated men often don't.
The three headliners have made their way in a hip-hop culture that largely treats women as playthings and conquests.
I am not surprised that none of this found its way into a series which largely treats spying as an upper-class English sport.
The study concentrated on the orbiter and orbit insertion, largely treating the in situ element as a black box with data relay requirements.
