Do cancers have a tendency to come back with better drug resistance if it's not fully eliminated? at least a resistance to the drug that got rid of it the previous time?
I think a cancer’s treatment resistance means losing differentiating marks and becoming more and more like a stem cell.
With these evolutionary processes it’s a given, the surviving mutation was already present at the time of treatment. The higher the genetic diversity the higher the chance of said mutations. A cancer’s genome is often highly unstable, since apoptosis is disabled, so diversity tends to be high.
Metastases usually imply a good chunk of "god mode" features gained already, for solid tissue cancers (soft tissue cancers are a bit different), so it’s a bad starting point. Imaging cannot detect any tumor below say 2mm, so ultimately you never know the true stage or treatment success. So a cancer doesn’t "return", it grows above the clinical threshold again.
Treatment is kinda a genetic tautology: If it works you didn’t had a treatment resistant cancer, if not you did. Or: If you lose, you never had a chance.
People say this because it sounds right and dramatic, but if they knew and understood what cancer is, they'd understand why treating it is so hard.
For those unconvinced, cancer is your own bodies cells gone rogue and trying to kill you. Now, this happens all the time. Luckily, our immune system is awesome and catches it.
Cancer is when your immune system does not catch it. it's invisible, indistinguishable from your skin cells or your lung cells. Its not like the flu or pneumonia - there is no foreign body, there is no attacker. Its you.
So then treatment means we need to kill living, actively reproducing cells in the human body. Well, a fire can do that.
The trick is, how do you kill the cancer cells, which your own immune system cannot even distinguish as cancer cells, but not harm your normal cells?
Turns out that's very hard and very grueling. Chemo is very effective, but you still lose your hair and damage just about all your organs in the process.
And, for the record, we do have "one off" cures for cancer - surgery. Just cut it out. The trouble is cells are microscopic and there's billions of them. Rarely will they be so perfectly contained you can get them all in one go. No, you miss some, and they sit there, growing, until the cancer is detectable again. And they move, they use your own blood and lymphatic system as a highway.
Though this reads as though the implied message is preaching the suppressed cure conspiracy theory so I'll respond to that interpretation.
What you're missing the competitive factor of this. If your drug strings your patients along while your competitor releases an effective cure, guess who's getting all the business? Look to Sovaldi and Keytruda for recent examples.
I wish I could find the article, but there is a clinic somewhere that ran trials where they deliberately wouldn’t treat the cancer too aggressively. Instead they experimented with treatment frequency but with control being the aim instead of elimination.
The theory being that they could keep it at bay indefinitely and lower the chance of selection pressure kicking in. The thought behind their approach is that they wanted their patients to die of something different than their cancer.
The same logic applies to cancer cells that you seen in antibiotic resistance. The treatment kills the cancer cells on which it's most effective, leaving the most resistant. When it comes back, they're all going to be resistant.
yes they are resistant to that line of therapy once it stops working.
Sometimes that resistance carries over to other lines too. For example, Enzalutamide doesn't work for prostate cancer if you were already treated by abiraterone.
