She gained prominence in Hong Kong and became popular in the Philippines as Cynthia Luster.
She began studying Gōjū-ryū Seigokan karate at Ennouji Dojo in junior high school.
She was one of Japan's brightest female martial artists during the 1980s and a leading figure in the girls with guns fad of Hong Kong action cinema.
[citation needed] Oshima portrayed "Farrah Cat" in Bioman, which aired not only in Japan originally but also worldwide.
She is commonly known to Western audiences as the actress in the Marlboro Lite commercials in the late 1990s.