The most common and most likely answer to this crossword clue is the 10 letter word PROGRESSED
I've seen this crossword clue in The Daily Telegraph
P
R
O
G
R
E
S
S
E
D
More clues leading to the result PROGRESSED
Buddy explains!

The straight part
We know that "Advanced" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case advanced = progressed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PROGRESSED mean?
PROGRESSED verb- To move, go, or proceed forward; to advance.
- To improve; to become better or more complete.
- To move (something) forward; to advance, to expedite.