A female patient, Chinese descent, aged 66, is referred from primary care with persistent cough, sputum with blood, shortness of breath and chest pain History Never smoked Recurrent bronchitis over past 5 years Has never been screened for lung cancer (by radiography or low-dose CT [LDCT]) Hypertension controlled on HCTZ; no diabetes, renal impairment Family history Grew up in China, moved to US at age 29; married for 30 years Grew up in family with heavy smokers Husband is current smoker LDCT reveals multiple tumors in left lung with pleural metastases Biopsy reveals non-small cell lung cancer Molecular analysis: EGFRmutation: G719X Negative forALKrearrangement Wild-typeKRAS The patient was started on afatinib, 40 mg once daily After one month on therapy, she reported having rather severe diarrhea (5 times/day) Treatment was discontinued, then re-started treatment at 30 mg/day