The impact of immunohistochemical or molecular markers on treatment selection and response was most pronounced in SDC. HER2 IHC2 + expression was observed across multiple subtypes, indicating that TDxd may represent a potential treatment option for more pts than previously anticipated. The impact of comprehensive genomic profiling on targeted treatment options is currently still modest.

Concurrent comprehensive genome profiling (FoundationOne® CDx) confirmed the LMNA-NTRK1 fusion, and treatment with the TRK inhibitor larotrectinib was started. With larotrectinib treatment, the tumor shrank in size at an early stage, and the response has been maintained for > 2 years.

At the time of this clinical case report, therapy is ongoing for 21 months without any signs of further disease progression. This study demonstrates the efficacy and safety of larotractinib as both adjuvant therapy and first-line therapy in a complex clinical case of colon cancer against the background of severe concomitant pathology, when chemotherapy is contraindicated.

This case highlights the potential of ROS1 as a therapeutic target in SCC, which has historically been considered rare, as ROS1-rearranged SCC accounts for only 0.2% according to the Foundation Medicine database. This underscores the importance of incorporating NGS into clinical practice, particularly for never smokers/light smokers or patients with advanced SCC of the lungs, to identify targetable mutations and guide personalized therapy.

P2, N=534, Active, not recruiting, Hoffmann-La Roche | Trial completion date: Dec 2025 --> May 2026 | Trial primary completion date: Dec 2025 --> May 2026

P1, N=15, Recruiting, Nationwide Children's Hospital | Trial completion date: Dec 2025 --> Dec 2036 | Trial primary completion date: Dec 2025 --> Dec 2026

Larotrectinib was used in 142 patients, demonstrating an 83.80% response rate, with low mortality (2.82%) and recurrence (2.11%) rates. Entrectinib had a lower response rate of 63.64%. We confirm the rarity of NTRK1-3 fusions in sarcomas. TRK inhibitors show high efficacy in sarcomas, emphasizing the necessity of genomic testing in all cases.Protocol registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD42024563594.

This case highlights the essential role of DNA methylation profiling in resolving diagnostic ambiguity and guiding targeted treatment in CNS tumors. It further supports the potential efficacy of entrectinib in NTRK fusion-positive glioneuronal tumors.

The ICER of larotrectinib therapy vs regorafenib therapy or larotrectinib therapy vs trifluridine/tipiracil therapy was calculated at 23,321.46 USD/QALY or 22,585.39 USD/QALY. From the perspective of healthcare payers in China, larotrectinib was cost-effective compared to standard of care as a second-line treatment or subsequent treatment for advanced or metastatic CRC patients with NTRK gene fusion-positive.

This case underscores the importance of integrating molecular diagnostics into the evaluation of atypical spindle cell tumors, particularly those presenting with aggressive clinical features despite low-grade histology. Early identification of NTRK fusions enables timely initiation of TRK inhibitor therapy, offering durable disease control and functional recovery. Broader awareness and implementation of molecular testing can greatly enhance the management of rare pediatric sarcomas.