Just my opinion/impression:
1) How to define "TCA is inhibited":
Sometimes it is not totally inhibited in that whole TCA Cycle. It has
another name: Truncated TCA cycle.
2) as xhzhou said: the intermediate products in glycolysis can enter into
other pathways---"whatever pathways"---synthesized into "macromolecules".
The "whatever pathways" & "macromolecules" are hot filed, which is more
complex than the textbook. Many of them are not discovered yet and may be
tumor-specific SUCH as the oncometabolites...etc
3) I also have the same doubt as you: If TCA Is really inhibited, where does
the acetyl-coa come from? [I don't think it is beta-oxidation. Ketone maybe
....]