Comparison of Cold-Cup Biopsy Versus Resection Biopsy in the Early Detection of Detrusor Muscle Invasion in the Case of Bladder Tumor

Bladder cancer continues to represent a major global health burden, and accurate early staging is crucial for planning an appropriate treatment strategy regarding the presence of detrusor muscle (DM) invasion. This is a prospective observational study, conducted at the Institute of Kidney Diseases, Hayatabad Medical Complex, Peshawar, from January to December 2024, to compare the diagnostic performance of cold-cup biopsy (CCB) over resection biopsy for the early diagnosis of histologically proven DM invasion. Consecutive non-probability sampling was used to enroll 104 patients (52 per group) aged ≥18 years with suspected bladder tumors. Preoperative workup consisted of cystoscopy, imaging, and documentation of the tumor. Methods included CCBs and resectional biopsies. The patients in both groups have comparable demographics and clinical characteristics. The former technique employed targeted mechanical samplings done at the base of the tumor, while the latter used loop excision. The specimens were reviewed by histopathologists blinded to the presence or absence of DM and invasion. The results suggest that although there is no difference in the diagnostic accuracy for muscle invasion of the two methods, the CCB technique provides better DM retrieval (86.5% vs. 65.4%; p = 0.013) and tissue adequacy, which could decrease the rate of re-intervention.