most often的字面意思是“最经常”（也可根据不同语境灵活处理）：

Cancer of the tongue develops most often in heavy users of alcohol and tobacco. 舌癌大最经常发生在烟酒瘾极大的人身上。

Such diseases are diagnosed most often in young women. 这类疾病最常在年轻女子身上查出。

It is the kind of tea most often served in Chinese restaurants. 这是中餐馆里最经常用的茶。