The effect of examining somatic alterations with NGS in patients with solid tumors, on patient management: A single-center experience in Turkey.

Objective: This study aimed to investigate the impact of analyzing somatic alterations using next-generation sequencing (NGS) on treatment management in patients with metastatic solid cancers and their ability to access NGS recommended treatments.

Methods: This retrospective study included eligible patients who underwent NGS on somatic tumor tissue. We examined the clinical and pathological characteristics of these patients and the alterations in their treatment following NGS results.

Results: A total of 101 patients who underwent NGS were included in the study. The most common cancers were non-small cell lung cancer (NSCLC), colorectal, and breast cancers, in that order. The median age was 58 (range 21-82) years, with 60 (59.4%) male participants. The median NGS turnaround time was 23 (range 17-29) days. NGS was performed on tissue from the primary lesion in 89(88%) patients. Predictive, prognostic, actionable, or variants of unknown significance were detected in 62(61.4%) patients. The most frequent variants identified were , and other rare mutations. Treatment was altered in 17(16.8%) patients based on NGS results. Of the 30 (29.7%) patients for whom NGS-informed treatment was recommended, only seven (6.9%) received the recommended therapy. There was no significant difference in overall survival (OS) between patients whose treatment was changed based on NGS results and those whose treatment remained unchanged (p = 0.897). There was no difference in OS between patients with and without variants (p = 0.384).

Conclusions: NGS analysis of somatic alterations in patients with metastatic cancer may reveal additional variants beyond those identified by baseline tests. However, based on the recommendations of the reimbursement institution in Turkey, only a limited number of patients are able to access treatments recommended by NGS results. Therefore, baseline tests established in Turkey need to be made available in more centers in an appropriate time.