MDLinxCase Challenge: The NRG1 Fusion That Opens a New Option in Metastatic PDAC—Can You Spot the Target?

🧩 Diagnostic Reasoning Exercise / Teaching Case

A 65-year-old woman with newly diagnosed metastatic pancreatic adenocarcinoma and liver metastases has type 2 diabetes, peripheral neuropathy, and ECOG performance status 2. She prioritizes quality of life and lives two hours from the treatment center. Family history includes ovarian and prostate cancer. Comprehensive tumor profiling and germline testing are pursued. After progression on initial treatment, molecular results introduce a new decision point. The challenge asks readers to weigh treatment fitness, interpret biomarker significance, and anticipate treatment-specific adverse effects.

Diagnostic Considerations

• Treatment fitness: Performance status, baseline neuropathy, and patient priorities complicate selection among first-line regimens.
• Treatment burden: Travel distance adds practical constraints beyond efficacy and toxicity.
• Molecular interpretation: Tumor findings require assessment of variant classification, assay coverage, and treatment eligibility.
• Hereditary context: Family history warrants attention, but tumor and germline findings answer different questions.
• Safety reasoning: Later questions distinguish common adverse effects from warnings requiring prevention or monitoring.

Practice Pearls

• Balance anticipated benefit against functional status, existing symptoms, and treatment logistics.
• Distinguish a detected molecular alteration from an established treatment indication.
• Review testing methodology and limitations before treating a negative result as comprehensive.
• Separate common side-effect counseling from serious-risk monitoring and infusion precautions.