A correct diagnosis is essential for the timely treatment of any condition — more so if the condition is life-threatening. New research has found that the efficiency of diagnostic staging using biopsy in bladder cancer patients is directly linked with their survival rates, meaning an inaccurate biopsy could even lead to death.

In the case of bladder cancer, a biopsy is the only way to make a definitive diagnosis where a small amount of tissue is removed from the bladder and examined under and tested for cancer. Accurate biopsy is essential for early treatment.

The two-year study conducted by UCLA researchers analyzed medical records of 1,865 patients who had "noninvasive" cancer, that is, cancer which had not yet spread into the muscle. They found that more than half of these patients were biopsied with insufficient material — no bladder wall muscle retrieved – to accurately stage the cancer. They also found that a subpar biopsy and incorrect tumor staging was associated with a significant increase in bladder cancer deaths.

"These findings are very important because while patients know about the stage of their cancer, they rarely question the quality of the biopsy," said lead author Karim Chamie in a statement. "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."

The main problem for incorrect biopsies, says Chamie, is that tissue is taken only from the inner lining of the bladder itself, ignoring the underlying muscle wall. If the cancer has started to metastasize it is important to examine muscle wall tissue for accurate diagnosis.

When the team examined the patients’ medical records they found that half the time there was an incomplete biopsy done or their extent of cancer invasion had not been clearly diagnosed by attending physicians.

When patients had aggressive tumors and their surgeons and pathologists appropriately staged them, the chance of dying of bladder cancer at five years was eight percent.

If the surgeon did an inadequate job staging them, but the pathologist alerted the physician of inadequate staging, the five-year mortality rate was 12 percent.

But if the pathologist failed to accurately diagnose the extent of cancer invasion then the five-year mortality was 19 percent.

"Appropriately staging patients with bladder cancer is a skill set that every urologist and pathologist should have in his/her armamentarium," Chamie said. "We believe the next step is to change the staging system for bladder cancer to incorporate the quality of staging. Not all stage I cancers are alike."

He explained how patients with stage II cancer, for example, who received an insufficient biopsy, may be undertreated as a result.

"I really do believe that one reason why we have yet to see significant improvement in bladder cancer survival over the last two decades may, in part, be attributed to inadequate staging," he added.

Along with patients, the study also included 335 urologists and 278 pathologists from medical institutes across Los Angeles County. Diagnosis based on muscle tissue was reported in only 52.1 percent of the cases and not mentioned at all in 17.7 percent of the reports.

This is grave misdiagnosis for a disease that claims 75,000 American lives each year, according to Chamie.

"The omission of muscle in the specimen or its mention in the pathology report in nearly half of all diagnostic resections is associated with increased mortality, particularly in patients with aggressive disease," he said. "Because urologists cannot reliably discern between aggressive and indolent disease, we recommend that patients with bladder cancer should undergo adequate muscle sampling at the time of biopsy."

Source: Chamie K et al. Quality of diagnostic staging in patients with bladder cancer: A process-outcomes link. Cancer. 2014.