1972 — Stigma

Philip Michael Thomas is an African-American doctor let out of federal jail early (he had been convicted of performing illegal abortions) in order to go to a fictitious Massachusetts island to assist the town doctor, who was his mentor at Harvard. When the old doctor dies, the newcomer is tasked with curing a town of a burgeoning syphilis epidemic while dealing with a racist, conservative Christian community in denial about the black doctor and the unfettered sexcapades of it’s children.

Oh, there are also a corrupt sheriff, a lighthouse keeper mad with syphilitic dementia, a lady of the night and her whorehouse, and what looks to be Willem Dafoe’s first cinematic appearance (IMDB lists his first role as appearing six years after this film).