Updated

A nationally renowned oncologist watched in anguish as his 9-year-old son was fatally hit by a cab just steps from their Upper West Side apartment Friday night.

The dad and boy were crossing the street at West End Avenue and 97th Street shortly before 9 p.m. — about a half hour after a 73-year-old man was killed in a separate accident two blocks away.

That man was struck and dragged by a private tour bus on Broadway and West 96th Street.

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A doorman heard the dad, Dr. Richard Stock, 51, cry out in horror after the cab hit young Cooper as it made a left turn onto West End Avenue.

"It was a terrifying scream," said Alex Lassi, the doorman.

Richard, who suffered a leg injury, and his son were taken to St. Luke’s Hospital, where Cooper was pronounced dead.

Richard is a radiation oncologist who treated former Mayor Rudy Giuliani for prostate cancer in 2000. He teaches at Mt. Sinai School of Medicine and lectures across the world on his specializations including prostate and bladder cancer.

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