{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T06:03:47Z","timestamp":1784527427765,"version":"3.55.0"},"reference-count":24,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T00:00:00Z","timestamp":1784505600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>Osimertinib resistance, particularly EGFR C797S without T790M, lacks established treatment strategies. We report a 71-year-old woman with stage IVB lung adenocarcinoma harboring EGFR L858R (T790M-negative) who received first-line osimertinib for 29 months until progression. Post-progression ctDNA revealed L858R\/C797S (T790M-negative) who received first-line osimertinib for 29 months until progression. Post-progression ctDNA revealed L858R\/C797S (T790M-negative). She was subsequently treated with icotinib 125 mg tid, achieving stable disease for 6 months. This case suggests that first-generation EGFR-TKI subsequent therapy may provide short-term disease control in this rare molecular context.<\/jats:p>","DOI":"10.3389\/fonc.2026.1911991","type":"journal-article","created":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T05:35:55Z","timestamp":1784525755000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Short-term disease control with subsequent icotinib therapy in EGFR L858R\/C797S, T790M-negative lung adenocarcinoma after osimertinib resistance"],"prefix":"10.3389","volume":"16","author":[{"given":"Shihang","family":"Song","sequence":"first","affiliation":[{"name":"Graduate School, Hebei North University","place":["Zhangjiakou, China"]},{"name":"Department of Oncology, Hebei General Hospital","place":["Shijiazhuang, 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