Tyrosine kinase inhibitor sunitinib therapy is effective in the treatment of bone metastasis from cancer of unknown primary: Identification of clinical and immunohistochemical biomarkers predicting survival

Bone metastasis from cancer of unknown primary (BMCUP) brings poor survival prognosis and its management remains controversial. Sunitinib (SUTENT) proved effective in many sorts of solid tumors but has never been applied for patients with occult primary cancers, and there is no study to identify sensitive or resistant biomarkers for sunitinib therapy in CUP patients. An analysis was carried out to investigate the efficacy of sunitinib by multivariate survival analysis of 286 patients with BMCUP. We further carried out multivariate analysis to identify histological and clinical biomarkers that could predict sensitivity or resistance for sunitinib therapy. Of the 286 patients included from January 2011 to March 2016, sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive and resistant biomarkers were identified in histological specimen of patients receiving sunitinib therapy. Clinical factors were also identified that predict poor survival prognosis for sunitinib therapy. Sunitinib therapy proved effective to prolong survival in patients with BMCUP. Sensitive markers for sunitinib therapy include KDR positivity and early-developed treatment-induced hypertension. Resistance factors for sunitinib include VEGF positivity, CAIX positivity and squamous cell carcinoma pathology type. Prolonged symptom time and severe weight loss before therapy seemed to be associated with poor survival prognosis for sunitinib therapy.