OBJECTIVES: Maintenance therapy can delay progression and prolong survival in metastatic non-small cell lung cancer (mNSCLC). The impact of treatments for mNSCLC on patient quality-of-life (QoL) is an important consideration, as treatment is non-curative and QoL in this population is already compromised. The SATURN study demonstrated that, compared with placebo, erlotinib maintenance therapy improved progression-free survival and overall survival by 41% and 23%, respectively. The impact of erlotinib maintenance therapy on QoL was also evaluated as a secondary endpoint. METHODS: Patient QoL was assessed until disease progression or withdrawal using the Functional Assessment of Cancer Therapy-Lung (FACT-L) questionnaire. Disease progression was assessed radiographically at regular intervals, often diagnosed prior to symptomatic progression. Patient QoL was analysed in terms of the time to symptom progression (TSP), time to deterioration (TTD) in trial outcome index (TOI) and time to deterioration (TTD) in QoL. An exploratory analysis based on the time to analgesia and appearance of key symptoms (pain, cough and dyspnoea) was also performed. RESULTS: FACT-L completion rates were above 90% at almost all study visits. At baseline, QoL measures were similar between the two treatment groups. Maintenance therapy with erlotinib did not negatively impact on QoL, compared with placebo, as illustrated by comparable TSP (HR=0.91 [0.74-1.12], n=785), TTD in TOI (HR=1.06 [0.87-1.31], n=781), or TTD in QoL (HR=0.96 [0.79-1.16], n=776). Exploratory analysis of NSCLC-related symptomatology showed that time to pain and time to analgesic use were significantly delayed in patients receiving erlotinib compared with placebo (HR=0.61 [0.42-0.88]; p=0.0080 and HR=0.66 [0.46-0.94]; p=0.0199, respectively). There was also a non-significant trend towards delayed time to cough and time to dyspnoea (HR=0.77 [0.49-1.21] and HR=0.75 [0.48-1.17], respectively). CONCLUSIONS: Erlotinib maintenance therapy significantly extends progression-free survival, without compromising patient QoL and with some improvement in symptoms.