When a liquid biopsy fails to detect the original EGFR driver mutation in a patient progressing on therapy, it should not be interpreted as the cancer losing its dependency. This result more likely indicates insufficient tumor DNA shedding, signaling that the test is uninformative and a tissue biopsy is needed.

A case study reveals the remarkable plasticity of EGFR-mutated lung cancer. After transforming from adenocarcinoma to small cell histology and receiving treatment, a subsequent biopsy showed it had reverted to adenocarcinoma. This highlights extreme tumor heterogeneity and the need for repeat biopsies upon progression.

For resected EGFR-mutated lung cancer, ctDNA status after surgery could personalize adjuvant osimertinib duration. A patient with initially positive ctDNA that clears on therapy is considered very high-risk for recurrence. This prompts discussion of continuing osimertinib indefinitely, beyond the standard three years.

The NeoADURA trial demonstrates that adding osimertinib in the neoadjuvant setting for EGFR-mutated NSCLC results in a 'humongous benefit' in major pathological response and nodal downstaging compared to chemotherapy alone, significantly improving surgical outcomes.

The FLORA two study's overall survival benefit was so compelling that clinicians should now default to osimertinib plus chemotherapy for most first-line EGFR-mutant NSCLC patients, only opting out for specific reasons like comorbidities or patient preference.

Patients with EGFR-mutant NSCLC that transforms into small cell lung cancer show poor responses to new therapies like tarlatamab, which are highly effective in de novo small cell cancer. This highlights a distinct biology that requires different therapeutic strategies and dedicated clinical trials.

Due to a 10-11 month overall survival benefit shown in the FLORA two regimen, leading oncologists now consider osimertinib plus chemotherapy the standard first-line treatment for metastatic EGFR-mutant NSCLC. Monotherapy is reserved only for patients who cannot tolerate or refuse chemotherapy.

When EGFR+ NSCLC transforms to small cell, clinicians often continue the TKI osimertinib alongside chemotherapy. This practice is largely based on expert consensus and the rationale of suppressing any remaining EGFR-driven clones, rather than on definitive clinical trial data showing a clear benefit.

The success of perioperative osimertinib means oncologists cannot choose the optimal strategy (targeted therapy vs. chemoimmunotherapy) for resectable lung cancer without first knowing the patient's EGFR, ALK, and PD-L1 status. This elevates biomarker profiling from a metastatic-setting tool to a critical first step in early-stage disease.