Bladder Tumor Substaging May Improve Outcome Predictions
TORONTO—Substaging of bladder cancer tumors provides important prognostic information that could help guide patient management decisions, according to researchers.
In a study of primary, non-muscle-invasive pT1 bladder tumors in 163 patients, investigators found that cancer that was only micro-invasive into the lamina propria at diagnosis was significantly less likely to progress to invasive disease and death compared with extensively invasive cancer.
“Future studies may lead to the incorporation of substage in the American Joint Committee on Cancer's TNM classification system for urinary bladder cancer,” concluded lead investigator Alexandre Zlotta, MD, PhD, Director of Uro-Oncology at the Murray Koffler Urologic Wellness Centre, Mount Sinai Hospital, and Professor of Surgery at the University of Toronto. Study findings were presented here at the Canadian Urological Association's 64th Annual Meeting.
Substaging of pT1 bladder cancer was pioneered by one of Dr. Zlotta's co-investigators, Bas van Rhijn, MD, and other researchers working in the Netherlands (Hum Pathol. 2005;36:981-986). Drs. van Rhijn and Zlotta subsequently carried this approach across the Atlantic.
Drs. Zlotta and van Rjihn, and their Canadian and Dutch co-investigators examined 69 bladder tumors from a hospital in Rotterdam and another 94 from a hospital in Toronto. Another team member, Theo van der Kwast, MD, conducted a pathology review of each tumor.
Forty tumors were designated at pT1m, or micro-invasive, and 93 others were deemed pT1e, or extensively invasive. Another 24 were downgraded from pT1 to pTa and six were upgraded from pT1 to pT2. Multivariate analyses revealed that tumors substaged to pT1e were significantly more likely to progress and lead to death. Carcinoma in situ was also associated with significantly increased likelihood of progression, as was female gender among patients with T1 tumors.
Commenting on the study, Shahrokh F. Shariat, MD, a urology fellow and faculty instructor at Memorial Sloan-Kettering Cancer Center in New York who has studied bladder cancer staging, said the study by Dr. Zlotta's group provides important information that can help guide disease management decisions.
“After external validation, substaging of the lamina propria should be included in the clinical decision-making regarding the management of clinical stage T1 bladder cancer,” Dr. Shariat said. “Patients who have T1 extensively invasive tumors, together with other features associated with biologically aggressive disease, should be counseled for early cystectomy.”