Locally Invasive Thyroid Metastases from Renal Cell Carcinoma: Surgery after Neoadjvant Therapy

Dana M. Hartl^*Mohamed Amine BANIAbir Al-GhuzlanAndreea-Elena SimonescuIngrid BreuskinAlix MarhicLAURENCE ALBIGESLivia LamartinaJulien Hadoux

• Gustave Roussy Cancer Campus, Villejuif, France

Neoadjuvant therapy is under investigation for unresectable clear cell renal cell carcinoma (ccRCC)(1) but also for locally invasive primary thyroid cancers.(2) Herein, we describe two cases of locally invasive thyroid metastases from ccRCC treated surgically after neoadjuvant therapy, to highlight the rationale and outcomes.Two patients, one female, one male, both age 69, developed unresectable thyroid metastases from ccRCC respectively 20 and 13 years after nephrectomy for ccRCC. Patient 1 received lenvatinib and a bispecific anti PD-1/CTLA-4 antibody in the context of a clinical trial. The second patient received nivolumab and cabozantinib.The observed tumor response in patient 1 showed a decrease in mean surgical complexity score from unresectable (prevertebral fascia invasion) to severe (risk of recurrent nerve paralysis), and in patient 2 from unresectable (prevertebral fascia) to moderate (superficial esophageal invasion). The recurrent nerve was invaded in patient 1, leading to a subtotal resection. Surgery was a total thyroidectomy extended to the internal jugular vein in patient 2. Hospitalization was 1 and 2 days respectively. Postoperative dysphonia improved in patient 1 after 3 months. No complications occurred in the second patient, who received adjuvant radiation therapy. After surgery, systemic therapy was discontinued in both patients, and stable residual oligometastatic disease was followed.Neoadjuvant therapy enabled a macroscopic resection of locally invasive thyroid metastases, preserving laryngeal function and allowing discontinuation of systemic therapy. This approach may be considered in these rare cases, although the impact on progression-free or overall survival is currently unknown.