What neoadjuvant strategies are recommended for downstaging locally advanced or borderline resectable renal cell carcinoma in an adult patient with adequate organ function and good performance status?

Neoadjuvant Strategies for Downstaging RCC

For locally advanced or borderline resectable renal cell carcinoma, combination immune checkpoint inhibitor plus tyrosine kinase inhibitor (ICI + TKI) therapy is the preferred neoadjuvant approach, though this remains investigational and should ideally be delivered within a clinical trial. 1

Current Evidence Status

The 2025 European Association of Urology guidelines explicitly state that neoadjuvant therapy is currently under investigation and available only in clinical trials, with no evidence yet demonstrating overall survival prolongation 1. However, emerging data show promising results that warrant consideration in select cases.

Treatment Options and Expected Outcomes

Combination ICI + TKI (Preferred Approach)

• Response rates: 26% partial response rate across studies, with radiographic tumor reduction ranging from -50% to +7.9% 2
• Tumor downstaging: Achieved in 53% of patients 3
• Thrombus reduction: 50% of patients with venous tumor thrombus showed Mayo level reduction 3
• Pathological response: Median viable tumor content of 30%, with 17.6% achieving complete pathological response (ypT0) 3
• Treatment duration: Median 7 months appears optimal based on recent data 3

This combination demonstrates higher objective response rates compared to monotherapy approaches 4.

TKI Monotherapy (Alternative)

• Shows mild to moderate tumor shrinkage
• Reduces tumor thrombus burden
• Improves operative complexity
• Increases number of patients eligible for surgical intervention 4
• Response rates lower than combination therapy (7-59% across retrospective series) 1

ICI Monotherapy (Not Recommended)

Limited efficacy demonstrated in early-phase studies 4. Should not be used as neoadjuvant monotherapy.

Surgical Feasibility and Safety

Critical finding: Surgery remains feasible in all patients receiving neoadjuvant therapy, with acceptable perioperative complication rates 3. Specifically:

• 17.6% experienced Clavien-Dindo grade ≥III complications (primarily in thrombus resections) 3
• No consistent increase in surgical morbidity across studies 4
• Median disease-free survival of 28 months in treated cohorts 3

Important Caveats

Radiological-Pathological Discordance

Major pitfall: No correlation exists between radiographic response and pathological response 3. This means:

• Imaging may overestimate or underestimate actual tumor response
• Pathological assessment using standardized INKCC criteria is essential 5
• Complete radiographic response does not guarantee complete pathological response

RCC-Specific Challenges

Renal cell carcinoma presents unique assessment difficulties 5:

• Large tumor volumes with variable baseline necrosis and fibrosis
• Architectural and cytological heterogeneity (good response in one area doesn't predict overall response)
• Viable tumor cells may persist despite apparent radiographic response

Clinical Algorithm for Patient Selection

Ideal candidates for neoadjuvant therapy:

1. Locally advanced disease (≥T3 or N1) without distant metastases
2. Venous tumor thrombus requiring complex surgical resection
3. Borderline resectable tumors where downstaging could improve surgical outcomes
4. Good performance status and adequate organ function
5. Access to clinical trial enrollment

Treatment protocol:

• Initiate combination ICI + TKI therapy
• Continue for approximately 7 months (median effective duration)
• Perform interval imaging to assess response
• Proceed to surgery regardless of radiographic response (surgery feasible in all cases)
• Ensure pathological assessment follows INKCC standardized criteria 5

What Remains Unknown

The degree of pathological response that predicts oncological outcomes is not yet established 5. Whether major pathological response (<10% residual tumor) differs clinically from complete pathological response (0% tumor) requires further investigation. Long-term survival data comparing neoadjuvant approaches to immediate surgery are lacking 1, 4.

The guideline panel's position is clear: neoadjuvant therapy should not be used outside clinical trials until higher-level evidence demonstrates survival benefit 1. However, for patients with locally advanced disease, particularly those with tumor thrombus or borderline resectability, enrollment in neoadjuvant trials using ICI + TKI combinations represents the most evidence-based investigational approach.