This is the 12926th most frequent Russian word.
лечении
"Treatment" or "therapy."
In this sentence, 'лечении' is used in the prepositional case, indicating the context of treatment or therapy.
Эффективность лечения зависит от правильно подобранной терапии.
The effectiveness of treatment depends on properly chosen therapy.
Here, 'лечении' is also in the prepositional case, referring to the topic of discussion concerning treatment.
Пациент рассказал врачу о своем лечении у народных целителей.
The patient told the doctor about his treatment by folk healers.
In this sentence, 'лечении' is used in an instrumental context, discussing the circumstances or conditions during treatment.