Stop in area to follow TV doctor (4)
I believe the answer is:
whoa
'stop' is the definition.
(I've seen this before)
'area to follow tv doctor' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'to follow' is a charade indicator (letters next to each other).
'tv doctor' becomes 'who' (I've seen this in other clues).
'a' put after 'who' is 'WHOA'.
'in' acts as a link.
(Other definitions for whoa that I've seen before include "Instruction to a horse to stop" , "Stop, Dobbin!" , "The King of rock and roll" , "Danger" , "Opposite of "Giddy-up!"" .)