Higher Tumor Classification and Grade for Nonmuscle-Invasive Bladder Cancer May Increase Recurrence and Progression Risk Up to Five Years

Study results demonstrated that patients with a higher tumor classification and grade when diagnosed with nonmuscle-invasive bladder cancer had a higher risk for recurrence and progression at one year and five years compared with lower classifications and grades.

“Bladder cancer disproportionately affects older adults,” said Dr. Tullika Garg, clinical investigator in the department of urology at Geisinger Medical Center in Danville, Pennsylvania, in an interview with CURE®. “It has the highest median age at diagnosis of all cancer sites (73 years), and patients with bladder cancer have very high rates of multimorbidity (the presence of multiple diseases or conditions). Providing tailored risk prediction of recurrence and progression in early-stage bladder cancer helps patients and physicians to engage in shared decision making for follow-up care based on the latest evidence. Bladder cancer is a burdensome, chronic condition in its own right, and using these data may help to redesign care for these older, medically complex adults.”

An estimated 75% of patients with bladder cancer have nonmuscle-invasive disease with a tumor classification less than T2, or a tumor smaller than 20 mm. This specific type of disease has one of the highest rates of recurrence compared with other cancer sites, although recurrence and the progression to muscle-invasive disease varies by tumor classification and grade at the time of first diagnosis. Several prediction tools are available for clinicians to calculate the risk for progression and recurrence, but they have a few limitations, such as not including enough detail and potentially not applying to American patients, the study authors wrote.

“Our current risk prediction tools for early-stage bladder cancer are binary,” said Garg. “The existing tools only predict whether someone will have a recurrence or not, or if a person will progress to more invasive disease or not. In this study, we developed predictions for the stage and grade of recurrence a person could have. This can help patients and urologists make decisions about how to conduct follow-up and surveillance for the cancer.”

In this study, researchers assessed data from 2,956 patients with nonmuscle-invasive bladder cancer with a tumor classification less than T2 who were diagnosed between 1994 to 2015. Tumor classification and grade for recurrences were used to formulate four outcome measures, all of which were computed for one year and five years:

• any recurrence;
• intermediate-risk recurrence or higher, defined as carcinoma in situ (in the original location), Ta high grade (noninvasive papillary carcinoma that can be easily removed, although it is likely to recur and grow) and T1 low grade (cancer spreading to connective tissue under the renal pelvis lining that may recur);
• high-risk recurrence, defined as T1 high grade (likely to recur and grow), or progression to muscle invasion; and
• progression to muscle invasion.

During a median follow-up of 29.4 months, 35.9% of patients had recurrences and 3.8% of patients progressed to muscle invasion. The risk for recurrence or progression increased based on tumor classification and grade at diagnosis. Patients with Ta high-grade tumors had less of a risk for recurrence or progression compared with those with T1 high-grade tumors. For example, patients with Ta high-grade tumors had a one-year predicted risk for recurrence or progression of 4.4% and a five-year predicted risk of 7.9%.

“For next steps, I think we need to better understand how adjuvant treatments (given in addition to the initial treatment) such as intravesical therapy (administering the drug directly to the bladder using a catheter) impact the risk predictions,” said Garg. “Ultimately, we would like to design a point-of-care tool that patients and physicians can use together in the clinic.”

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