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Mitomycin and hemocyanin of differing benefit in bladder cancer

NEW YORK (Reuters Health) – After resection of non-muscle-invasive bladder cancer (NMIBC) without carcinoma in situ, mitomycin more effectively prevents recurrence but keyhole limpet hemocyanin (KLH) tends to be better at preventing progression.

In a May 14 online paper in the Journal of Clinical Oncology, Dr. J. Alfred Witjes of Radboud University Nijmegen Medical Centre and colleagues note that in 2008 there were more than 360,000 cases of bladder urothelial cell carcinoma, and 150,000 deaths from this disease. About 70% are NMIBC and the risk of recurrence and progression after treatment varies.

Treatment is generally transurethral, and patients can receive adjuvant chemotherapy with agents such as mitomycin, or immunotherapy with, for example, Bacillus Calmette-Guerin (BCG).

However, recurrences and adverse events are common. KLH has shown some benefit in small trials. Although current guidelines recommend use of BCG it’s unclear whether it’s superior to mitomycin.

To investigate further, the team studied 853 patients with intermediate- and high-risk NMIBC and pTa/1 grade 2 to 3 tumor, or multiple or recurrent pTa grade 1 tumors.

After transurethral resection they were randomly assigned to 16 intravesical instillations of KLH after preimmunization or 11 intravesical instillations of mitomycin.

Patients were comparable but there were significantly more pT1 tumors in the mitomycin group (28% vs 19%).

KLH was less effective than mitomycin in recurrence free survival (median 106 vs 297 weeks). In the KLH group, 61% developed recurrence, compared to 34% of the mitomycin group.

The risk of progression was significantly less with KLH, however. Five of the 283 KLH patients had disease progression, compared to 15 of the 270 in the mitomycin group.

“KLH had a different safety profile and was inferior to mitomycin in preventing NMIBC recurrences. KLH tended to be more effective than mitomycin in preventing progression,” the authors summarized.

Nevertheless, they add, the “larger number of patients with pT1 tumors in the mitomycin group might have introduced a bias. Because our results on progression are conflicting and paradoxical compared with the results of other studies, further research should focus on clarifying this.”

Dr. Witjes did not respond to requests for comments.


J Clin Oncol 2012.