A new study suggests that the presence of bladder cancer in the bladder neck or the trigone (a sensitive, triangular area at the base of the bladder) is associated with a higher risk of the disease returning or advancing in high-grade non-muscle-invasive bladder cancer (NMIBC).
Specifically, involvement in these areas was linked to shorter periods of high-grade recurrence-free survival (the time a patient remains free from the return of aggressive cancer) and progression-free survival (the time before the cancer grows deeper into the bladder wall or spreads to distant sites).
Researchers analyzed data from a multicenter cohort of 1,796 patients with high-grade NMIBC who were treated with tumor resection and adjuvant Bacillus Calmette-Guérin (BCG) therapy.
The study, published in Annals of Surgical Oncology, found that patients whose tumors were located in the trigone or bladder neck had a 24% higher risk of the cancer returning as high-grade disease. Furthermore, these specific locations were independently associated with a 45% increased risk of the cancer progressing to a more advanced stage, even after adjusting for other clinical factors.
“These findings suggest that tumor location should be considered a prognostic variable, raising the question of whether involvement of the trigone or bladder neck should be integrated into clinical risk stratification models for high-grade NMIBC,” the study’s authors noted.
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To ensure the reliability of these findings, the results were validated using an extensive collection of real-world patient records covering 20,249 additional cases.
In this specific validation group, researchers found that tumors located in the trigone or bladder neck were significantly linked to higher rates of both cancer-specific mortality (death caused directly by the bladder cancer) and overall mortality (death from any cause).
The authors discussed several potential reasons why these locations are riskier, including their unique cellular structure, constant exposure to urine markers, and the technical difficulty of performing surgery in these areas; however, these considerations remain speculative and require further study.
Interestingly, the study found that the negative impact of tumor location appeared to diminish in patients who completed at least one year of BCG maintenance therapy.
While this suggests that long-term treatment may help offset some anatomical risks, the researchers emphasized that these findings are exploratory. Because the results could be influenced by certain statistical biases, further research is needed to confirm whether prolonged BCG exposure definitively cancels out the risks associated with tumor location.
Further prospective research is also required to confirm the practical benefit of adding tumor location to current risk assessment models before it can be officially recommended for routine use.
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