The absence of muscle in the specimen in nearly 50% of all diagnostic resections for bladder cancer was linked to increased mortality, particularly among patients with high-grade disease.
These findings suggest inadequate cancer staging by either the urologist or the pathologist, the researchers wrote.
“These findings are very important because while patients know about the stage of their cancer, they rarely question the quality of the biopsy,” researcher Karim Chamie, MD, assistant professor of urology at the UCLA Jonsson Comprehensive Cancer Center, said in a press release. “We hope these findings will help empower patients to ask about the quality of their biopsy and, if it is suboptimal, then urge their doctors to repeat the biopsy prior to deciding on what type of treatment to prescribe.”
Chamie and colleagues reviewed the Los Angeles SEER registry to identify the records of 1,865 consecutive patients in Los Angeles County diagnosed with nonmuscle-invasive (stage Ta, Tis and T1) urothelial carcinoma of the bladder. The median patient age was 73 years, and the study population was 76.5% male.
Patient medical charts were used to obtain the following information: cancer center where resection was performed, operating urologist, reporting pathologist, quality of staging and TNM staging. The investigators then merged these data with the SEER database to determine patient demographics, tumor characteristics and follow-up information. They stratified staging quality based on the presence, absence or reference to detrusor muscle in the pathology report.
The researchers used chi-square test analysis to correlate the categorical variables with the existence or mention of detrusor muscle. They then used a multivariate model to establish the correlations between staging quality with patient demographics and tumor characteristics.
Researchers determined bladder cancer-related mortality rates through a maximum likelihood, competing-risks regression model. The event of interest was defined as bladder cancer-related death, whereas the competing event was noncancer-related death. The model adjusted for several demographic variables. The estimates were expressed as sub-hazard ratios with 95% CIs.
The researchers found that in the initial pathology reports, muscle was reported as present in 972 (52.1%) of the specimens, as absent in 564 (30.2%) of the specimens and not mentioned in 329 (17.7%) cases. The grade or depth of cancer invasion did not appear to affect the presence of muscle in the specimens.
Staging quality was correlated with mortality (P<.05). The 5-year cancer-specific mortality among patients with high-grade disease was as follows; 8% when muscle was present in the specimen, 13% when muscle was absent and 21.5% when muscle was not mentioned in the report.
“Appropriately staging patients with bladder cancer is a skill set that every urologist and pathologist should have in his/her armamentarium,” Chamie said. “Not all stage I cancers are alike. Some patients may have stage II cancer, but because the biopsy was insufficient, these patients were inaccurately staged and may be undertreated. I really do believe that one reason why we have yet to see significant improvement in bladder cancer survival over the last 2 decades may, in part, be attributed to inadequate staging.”
Disclosure: The researchers report no relevant financial disclosures.