Background

Sunitinib treatment for patients (pts) with metastatic renal cancer (mRCC) can often lead to fatigue. The incidence of Sunitinib-associated hypothyroidism (HT) in the phase III pivotal study of pts with mRCC was 14% for all grades and 2% for grades 3-4. Subsequent retrospective and prospective studies described incidences of between 30–85%. Elevated TSH (Thyroid stimulating hormone) alone may be seen in up to 85% of mRCC pts treated with Sunitinib. Symptoms of HT, eg: fatigue, constipation, cold intolerance, hair thinning and dry skin, have been reported in the majority of Sunitinib treated pts.

Methods

We reviewed all cases of mRCC pts in the St James’s Institute of Oncology initiating Sunitinib treatment between Jan 2008 and Dec 2009 using the electronic record system Patient Pathway Manager. Pts with underlying HT, abnormal TFTs (thyroid function tests) at baseline or those on Sunitinib for less than two cycles were excluded. TFTs were performed at baseline and then Day 1 of every two cycles. Response was assessed every 2-3 cycles. The aims of the study were to identify the rate of Sunitinib-associated HT and determine whether there was a correlation between HT and disease response.

Results

84 pts were included (median age 62 years). 90% had good or intermediate prognosis disease by Memorial Sloan-Kettering Cancer Centre (MSKCC) criteria. 52 pts had TSH <6mU/L and 32 had TSH of >6mU/L. Progression-free survival was significantly longer in those pts with TSH of >6mU/L (29.6 months) compared to those with TSH <6mU/L (11.3 months).

Conclusion

Sunitinib -associated HT occurred in 38% of pts and predicted for improved outcome. Further studies are needed to determine whether TFTs would be a useful biomarker.