@Prime time, I am so sorry that you've had some troubles with the abscess .... that was extremely unfortunate.
The use of Chemo, Surgery, Chemo has been around for a decade or more - as the ladies above have said, one of the best ways to hit the rogue cells that may have already 'left the room'. So THEY are targeted with the first lot of chemo - not only to hit & destroy THEM - but to hopefully reduce the tumours as well prior to surgery.
When my husband was diagnosed with aggressive stomach cancer in 2010 - the Chemo/Surgery/Chemo regime is what was supposed to happen to him, but his tumour was blocking food exiting from his stomach, so they had to omit the first lot of chemo & just do the surgery & follow up chemo as he was too thin and was actually mal nourished (weighing in at just 50kg.) I was scared shitless, thinking he was going to die - as having read up on it & spoken with a buddy in the US who was a colon cancer specialist who said it was really really serious ... 75% don't usually survive 5 years with many of those not surviving 2 years. He went on to make a remarkable recovery & is still with me today - eating full meals after 6 months & going back to competing in Triathlons, his main love just 6 months after finishing chemo. He even went back to competing and winning in Triathlon World Championships around the world again! He was 75 at the time. You can read his story here:
https://onlinenetwork.bcna.org.au/discussion/18896/doing-what-you-love-to-do-before-during-after-bc-whats-your-favourite/p5Your mind can really play tricks on you - try not to second guess your treatment - just know that your team is putting together the best treatment possible for your diagnosis.
All the best for your ongoing treatment xxx I hope you don't hit any other speed humps xxx