Ongoing Melanoma

Hi,first of all I’m sorry if this seems negative but still trying to get my head around it all.My wife had a mole she presented to the doctor with concerns with,it was dismissed and eventually turned out to be Melanoma.A CT in Nov ‘22 showed lymph nodes involved so a decision as to treatment or surgery first was required.They decided on surgery to remove the lymph nodes in her armpit but had a CT done 6days before the surgery.My wife was told,as she was recovering in hospital,the CT showed nodules in the lungs.My question is,surely a CT should be done with enough time before surgery to determine whether treatment should be started before the surgery as the disease had already travelled? The upshot is,from the CT scan showing the disease had mastisized,it was 7 weeks until she started he double dose immunotherapy.She then had an MRI due to arm twitches which showed 3 areas in the brain.She has since had her 3rd session of Immunotherapy,had brain surgery to remove the larger lesion and about to have her 4th double dose session next week.However,after a CT scan yesterday,due to her having bad heads,the melanoma is showing in more places,liver,adrenal glands and stomach but some lumps on her neck and jaw are showing signs of shrinking suggesting the immunotherapy is starting to work so they’ve decided to go for the 4th session then maybe targeted therapy and radiotherapy on the brain lesions.So sorry for the long post,but again my question and perhaps advice is anyone else in this situation,please question the timings of any CT scan pre surgery so they have the results and options to suspend surgery and start treatment if needed.I may be completely wrong but it feels if they’d known in our case the disease had already moved on from the lymph nodes,they may have started treatment first.Any thoughts are welcome but I know it’s all ifs and buts.Just feels we’re playing catch up and the cancer is one step ahead all the time but hopefully the lumps reducing is a sign the immunotherapy is starting to take effect.