I am so sorry to hear that cancer was found in the lmph nodes inspite of partial cystectomy.
Also thank you updating us the status. It helps everyone of us understand more about adenocarcinoma and its treatment which is considered rare type of bladder cancer. I understand that adenoma carcinoma is the cancer that starts in the glands which produces mucus. So, colon, breasts, lungs, pancreas and prostate which has many glands in its organ seem to have high occurance for adenocarcinoma. I did not think there were glands in the bladder because I do not know the role of glands in the bladder.
Wikipedia says 5FU is often used as a treatment for colon cancer. 5FU is a type of chemo agent which inhibit duplication of DNA in cell divicion, in effect stops prolification of cancer cells (normal cells too). Since most of colon cancers are adenocarcinoma, it sounds like it is used for adenomacarcinoma of bladder.
Optivo and Yervoy are immuotherapy drugs, but they have different mechanism of actions. In 2018, two scientists were awarded Nobel prize for discovery of immunotherapies. Dr. Honjo of Japan was awarded for his discovery of immune check point inhibitor. Immune check point (PD-1, PD-L1) inhibitor is what we usually use for bladder cancer. Several check point inhibitors which were commercialized are Keytruda by Merck, Tecentriq by Roche, Optivo by Bristol Meyers Squibb. Keytruda is T-cell PD-1 checkpoint inhibitor and is well known and used for bladder cancer treatment. Optivo is also PD-1 checkpoint inhibitor. So, w can consider Optivo and Keytruda as almos the same immunotherapy drugs. The other Nobel prize recipient in 2019 for Medicne is Dr. Allison of the USA for his discovery of immunotherapy to inhibit T-cell CTLA-4 protein which is acting as brakes to attack cancer cells. PD-L1 inhibitor has shown to kill advanced bladder cancer cellls and Keyruda has been notably used to treat bladder cancer. As per your reference CTLA-4 and PD-1/PD-L1 inhibitor combination have shown to inhibits tumor growth in colon cancer. As colon cancer is mostly adenocarcinoma, there is a hope that it can work for adenocarcinoma gladder cancer as well, so I understand.
Incidentally, mismatching which the article you refered mentions was termed because a wrong nucleotide was paired. Cancer is abornomal cells. Abnormal cells are produced because of abnormal genes in DNA. If abnormal genes are proteins which have imortant function, the cell which is made up with many proteins behave abnormally and can have features of cancer cells. DNA is a long string of many genes - some are used to produce protein and some are just for other traits such as eye color, etc. DNA string is made of four different nucelotides, A,G,C,T, coding information. Actually DNA is made of two long strings of A,G,C,T. One string has all the information to make up our entire body, but because the information on DNA is so critical to be correc because every cell in our body has the exactly same information, there is second string which goes in oposit direction with A on one string is paired with T on the other string. G on one string is paired with C. But our body sometimes mistake and make a mistake and A on one string get paired with C instead of T on other string. This is called mismatching. Out body has evolved to be smart so when this mismatching happnes it will correct itself. But some people's body cannot repair this mismatching. If this mismatching is not repaired before the cell is divided, it can cause abnormal genes , subsequently protein which cannot perform intended function, thus creating abornomal cell, which might become cancer cell.
Anyway, I hope you 5FU and radiation work for your husband. Also those new treatments for adenocarcinoma for other organs will become available for adenocacinoma of bladder.