There are few reports on the efficacy of second-line chemotherapy in patients with cancer of unknown primary site (CUP). We tried to reveal the effectiveness of second-line chemotherapy on CUP patients.Methods
We retrospectively analyzed the clinical outcomes of second-line chemotherapy in patients with CUP of the unfavorable-risk group.Results
Among 110 CUP patients between May 2002 and January 2012, unfavorable-risk patients are 67 patients. Total of 32 patients (48% of unfavorable-risk patients) were able to receive second-line chemotherapy. Of these patients, 6 (19%) showed an objective partial response to second-line chemotherapy, 15 (48%) showed stable disease response after receiving second-line chemotherapy. Median progression-free survival of second-line therapy is 90 days (range; 11–503). Mean overall survival is 366 days (range; 138–1676) in 32 unfavorable-risk CUP patients who could receive second-line chemotherapy; however, 106 days (range; 5–787) in 28 patients who could not receive. Among the 32 patients who could receive second-line chemotherapy, these who responded first-line chemotherapy (first-line chemotherapy most response; PR or SD) may be favorable progression-free survival in second-line chemotherapy (P = 0.0398).Conclusion
Second-line chemotherapy may be beneficent for unfavorable-risk CUP patients who had good response to first-line chemotherapy.