Impact of Tissue Biopsy Prior to Systemic Therapy on Treatment Decisions and Early Outcomes in Metastatic Renal Cell Carcinoma

Background: Metastatic renal cell carcinoma (mRCC) is a biologically heterogeneous malignancy with evolving systemic treatment options. Tissue biopsy is traditionally recommended for histological confirmation and therapeutic planning; however, its necessity prior to initiation of systemic therapy remains debated, particularly when delays in treatment initiation may cause higher loss to follow-up in the biopsy group and the system-delay in a resource-limited setting.

Objectives: To evaluate the role of tissue biopsy prior to initiation of palliative therapy in metastatic renal cell carcinoma with respect to treatment selection, treatment initiation delay, early clinical outcomes, and follow-up status.

Methods: This retrospective observational study included 68 patients with metastatic renal cell carcinoma who received palliative systemic therapy. Patients were categorized into biopsy (n=40) and non-biopsy (n=28) groups. Data collected included demographic characteristics, IMDC risk stratification, treatment modality, time to treatment initiation, early treatment response, and follow-up status. Comparisons were performed using Chi-square or Student’s t-test, with a p-value <0.05 considered statistically significant.

Results: Baseline characteristics and IMDC risk distribution were comparable between the biopsy and non-biopsy groups (p>0.05). Treatment selection differed significantly between groups. Immunotherapy or combination therapy was used in 35.0% of patients in the biopsy group compared to 14.3% in the non-biopsy group (p=0.03), while TKI monotherapy was more frequent in the non-biopsy group (50.0% vs 30.0%; p=0.04). The mean time to initiation of palliative therapy was significantly longer in patients undergoing biopsy (18.6 ± 6.4 days) compared to those without biopsy (10.2 ± 4.8 days; p<0.001), and a delay of more than 14 days was observed in 60.0% versus 21.4% of patients, respectively (p=0.002). Treatment response at first radiological or clinical assessment did not differ significantly between the biopsy and non-biopsy groups, with stable disease observed in 45.0% and 46.4% of patients, respectively (p=0.90). Loss to follow-up was significantly higher in the biopsy group (40.0%) compared to the non-biopsy group (21.4%; p=0.04).

Conclusion: Tissue biopsy prior to initiation of palliative therapy in metastatic renal cell carcinoma may plays an important role in treatment individualization but is associated with treatment delays and higher loss to follow-up, without a demonstrable short-term outcome benefit. A selective, patient-centered approach to biopsy may help optimize timely therapy initiation while preserving diagnostic value.