Unique natural history of an EGFR mutated adenocarcinoma.

Background: Supportive care alone cannot be indicated for cancers for which established standard therapy exists unless there is a specific reason. Due to the refusal of standard therapy by the patient after proper explanation of the therapy, we experienced a long-term follow-up of >10 years with supportive care alone in an epidermal growth factor receptor (EGFR) mutated lung cancer patient.

Case: A 70-year-old woman was referred due to the right lung with some ground glass opacities (GGOs). One of the GGOs which was resected in another hospital had been confirmed to be EGFR mutation-positive lung adenocarcinoma. Although EGFR-tyrosine kinase inhibitor (TKI) was explained to be the standard therapy, the patient refused receiving the therapy and wished to follow up imaging of the remaining GGOs. During the follow-up period of 13 years, the each GGO showed a gradual increase. The doubling time of the largest GGO and that of serum carcinoembryonic antigen was > 2,000 days, respectively.

Conclusion: Although very rare, some of EGFR mutated lung adenocarcinoma might have a very slow progression. Clinical course of this patient provides useful information to the clinical practice of future patients who may have similar clinical courses.