It has not only been used for a year according to this research. It is false that every patent who has used it has not had a reoccurrence. Maybe none of his patients have had a recurrence but that is different from all patients in general.
There have been a number of studies and it is a promising treatment option. This link is to a study where they researched prior studies going back to intravesicle treatments for noninvasive bladder cancer in 1947.
www.ncbi.nlm.nih.gov/pubmed/22259002
You should read the whole article as it is informative and gives recurrence and progression facts based on a number of studies.
"Author's Conclusion: A single dose immediately following surgery is ineffective based on one study. Gemcitabine may be more active than mitomycin C with a lower toxicity profile. Compared to intravesical BCG therapy, gemcitabine had similar effects in intermediate risk patients, less effective in high risk patient and superior in BCG refractory patients. However, each randomised trial identified represents a different clinical setting in NMIBC and therefore the evidence base is limited. Consequently these data should be interpreted with caution until further corroborative evidence becomes available. The aim of intravesical therapy in NMIBC is to prevent tumour recurrence and progression and to avoid the morbidity associated with cystectomy. Intravesical gemcitabine is a promising drug that may add to the urologist's options in achieving this goal."
If you Google "intravesicle gemcitabine" you will find lots of good information on studies. That have been done.
Mike