Thank you boxhill; you’ve explained in much better terms than I could something that’s been bugging me for ages.
The difference in survival stats for stages 1, 2 & 3 are actually fairly modest, then it’s a big jump to stage 4. However the stats for stage 4 after ‘curative’ resection are actually comparably closer to stage 3 (compared to unresected stage 4). So in my mind differentiating on resectability in staging or sub-staging would be a far more useful prognostic factor than say tumour depth (ie the difference between stage 1 & 2). I guess the issue is that resectability is not an objective measure that can be assessed radiologically, but comes down to the opinion, skill and aggressiveness of a particular surgeon.
There are also other factors that are not considered in staging such as MSI, cell differentiation and genomic mutation status that can be as prognostically useful if not more so than some of the stage or sub-stage distinctions.
The other issue is one of lead time bias. Because the survival stats are based on # of years after diagnosis, a patient who is diagnosed shortly after progressing to stage 4 will naturally live longer on average than one who has been stage 4 for a long time (not considering the extent of metastatic spread in this case).
Of course the fundamental issue is that you can’t take population average survival stats as prognostic for an individual. The average individual also has one breast and one testicle. As my onc says, your individual possible outcomes for being alive in 5 years are either 100% or 0%, and I can’t tell you which it will be until the time comes.
10/2018 Dx RC, 12cm high
Mod diff, EMVI+ LVI+. 4 liver mets
pT3N1aM1a Stage IVa. MSS NRAS G13R
CEA: Nov-18= 14, Mar-19= 2.4, Aug-19 <2.0, Mar-20=2.2, May-20=1.9, Jun-20=2.1, Sep-20: 2.1, Dec-20: 2.3, Mar-21=2.5
11/18 FOLFOX x6
3/19 Liver resection
5/19 25x pelvic radiation; complete met. response
07/19 ULAR w ileo, 1/27 LN+
08/19 Found liver spot
08/19 FOLFOX x1, FOLFOXIRI x1, FOLFIRI x5
12/19 Liver resection
02/20 Ileo reversed
03/20 NED (CT/PET/MRI/scope) - latest scans Mar ‘21