Does sunitinib-induced hypothyroidism play a role in the activity of sunitinib in metastatic renal cell carcinoma?

BACKGROUND

The objective of this study was to evaluate if hypothyroidism developing during sunitib therapy in patients with metastatic renal cell carcinoma (mRCC) is associated with a better outcome.

METHODS

Thirty-one consecutive patients with clear cell mRCC were retrospectively analyzed. Thyroid function was assessed prior to therapy, every 6 weeks during the first 6 months and every 2-4 months thereafter. Hypothyroidism was considered present if thyroid-stimulating hormone (TSH) exceeded the upper normal limit (UNL) with normal triiodothyronine (T3) and thyroxine (T4).

RESULTS

Hypothyroidism occurred in 16 patients (52%) within 3 months (range 0.7-22.9) of treatment initiation. Thyroid replacement corrected TSH below the UNL in 10 patients (63%). The distribution according to Motzer prognostic criteria revealed good prognosis in 16 patients (52%), intermediate in 9 (29%) and poor in 6 (19%). The hypothyroid patients tended to have longer progression-free survival (PFS; median 12.2 vs. 9.4 months; p = 0.234) and longer survival (median 22.4 vs. 13.9 months; p = 0.234) than the euthyroid patients. Clinical benefits were similar in both groups.

CONCLUSIONS

Hypothyroidism that develops in mRCC patients treated with sunitinib is associated with a trend toward prolonged PFS and survival, with a similar clinical benefit rate.