Hi Rosemary and Chris,
I'm sorry to say that even grade 1, Ta tumors may sometimes, rarely-less than 5% of the time- recur as more aggressive tumors or even metastasize. I have met a few people who have started out with ta, g1 tumors and who are no longer with us. This is the reason a person with a ta, G1 tumors must continue with follow up forever.
There is a very rare type of 'tumor' known as polyps or papilloma, and these are almost certainly not cancerous, while Ta, g1 tumors are of abnormal cell growth:
"Both papilloma and papillary urothelial neoplasm of low malignant potential may develop recurrent or new papillary lesions but only the latter may be associated with invasion or metastases in rare cases. The study by Magi-Galluzzi and Epstein disclosed the clinical behavior of 34 de novo papillomas. The follow-up showed that 6 patients had recurrent disease but none progression to either lamina propria (T1) or muscularis propria (T2) invasion. This paper confirms that papilloma and papillary neoplasm of low malignant potential should be considered separately. The urologist should follow-up patients with papilloma but because they have a low incidence of recurrence and rarely progress to develop noninvasive urothelial carcinoma, it seems reasonable to avoid labeling these patients as having cancer."
By the way I got that statistic from a number of different sources, and have read it time and time again, sometimes it's a bit lower, 3%. I'd say 10% rate of progression for ta, g1 tumors is the highest number I've seen in an article about bladder cancer.
Wim Oosterlinck is very famous in Europe and is the head of the genito-urinary oncology division of the European Org. of Cancer Research and Treatments, head author of all guidelines for blc in Europe and someone I've quoted extensively on the webcafe site.
blcwebcafe.org/superficialblca.asp
Rosemary, I think that article you gave the link to is from Sept. '03 - the hint is in the link.
T1 tumors are dangerous because they are a form of cancer that has already invaded, different from Ta, g1 tumors in that respect. If a person has a combination of T1 and CIS, bladder removal is the safest bet.
Take care,
Wendy