[yaakov34]

It's a very big improvement, relative to most cancer treatment advances, assuming it holds up and produces at least temporary remissions for these patients. "Previously treated advanced cancer" means widespread metastatic cancer that has already shown resistance against current therapies. Basically, this is end-stage cancer, with next to no options for the patients. If a treatment approach has been found, it will be extended to more patients and improved. Of course, they won't just rest on their laurels.

Most advances in cancer treatment (which have together added many years to the lives of cancer patients) are actually much smaller than this: a few weeks added to life expectancy here and a small improvement to the survival rate there. But they steadily add up.