4952 - Next-generation sequencing for better treatment strategy of cancer of unknown primary (CUP)

Background

Cancer of unknown primary (CUP) consists of diverse histology types of cancer and have shown poor prognosis. In the era of precision medicine, next-generation sequencing (NGS) may contribute new therapeutic target which could improve treatment outcomes of CUP.

Methods

Patients who were diagnosed with CUP and underwent NGS exam between August 2017 and August 2018 at Samsung medical center were included for the study. NGS data were analyzed, and medical records were reviewed retrospectively to evaluate clinical characteristics and response to various treatments.

Results

A total of 21 patients with CUP who had NGS data were analyzed. The median age was 58 (range, 35-78 years). Male was dominant (57.1%) and most of the patients were ECOG 1 (90.5%). Among the patients, 14 (66.7%) were poorly differentiated carcinoma, 6 (28.6%) patients were adenocarcinoma, and one patient was squamous cell carcinoma. Most common metastatic site was lymph node (57.1%), followed by bone (38.1%), lung (19.0%), pleura (19.0%). Paclitaxel combined with carboplatin was most frequently used regimen for the first-line treatment (57.1%). Cisplatin-based chemotherapy was used second most (28.6%). One patient showed complete remission during the first-line treatment whereas 7 patients and 5 patients achieved the best response of partial response and stable disease, respectively. Median progression-free survival was 4 months (95% CI: 0.316-7.684), and median overall survival was not reached. Except four patients, 17 (81.0%) patients showed 25 gene alterations on the NGS results. TP53 mutation was observed most commonly (n = 6, 25.6%), followed by ERBB2 alterations (n = 3, mutations [n = 2], amplification [n = 1]), KRAS mutation (n = 2), MET amplification (n = 2), CDKN2A deletion (n = 2), and MYC amplification (n = 2). One patient harbored ERBB2 amplification was treated with trastuzumab combined with paclitaxel, and the patient demonstrated sustained partial response at 9 months, until the data cut-off date.

Conclusions

Most of CUP patients had variety actionable gene alterations. Precision medicine based on molecular analysis with NGS will improve the prognosis of the patients with CUP.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.