There are a few factors at play here, I think

* Many breakthroughs from the first research stages never make it into medical application.

* Many breakthroughs are touted as some kind of "novel treatment", but when they get into the hands of the doctor, they talk about it as chemotherapy, because it kills cancer cells. So you might not even notice that you're getting something novel.

* Many breakthroughs take decades until they actually land in mainstream treatment.

* Many breakthroughs are specific to some kinds of cancer.

That said, in most developed countries, survival rates/times for cancer have been steadily improving for decades.

It's a bit like with solar cell and battery tech breakthroughs: you hear about them all the time, but it takes 20 to 30 years until they make it to production. But both have been improving steadily for an impressively long time.