This study is a prospective non-randomised control study to evaluate the efficacy of a physical activity promotion program on the experience of physical activity in patients with stage III and IV non-small cell lung cancer (NSCLC) with documented disease control (stable disease, partial or complete response defined by RECIST V1.1) at least 6 months after start of first line treatment.

The trial will consist of 4 visits. An outpatient clinic visit in which the eligible patients are invited (V1), a screenings visit (V2), a third visit (V3) at which the patients will be divided into the intervention or the control group, according to owning a smartphone and their affinity with it, followed by the start of the intervention consisting of 8 weeks telecoaching by means of an application and step counter and a final visit (V4) 8 weeks after starting up the intervention.

The objective of this pilot study is to investigate if physical activity can be improved by telecoaching in patients with advanced stages of lung cancer in remission. We hypothesize that a smartphone application, designed for a population with respiratory symptoms, will increase daily physical activity, which translates into significant improvements on quality of life. This uncontrolled pilot study will therefore address if a 8-week PA promotion telecoaching program in addition to usual care has the potential to improve physical activity and quality of life in patients with lung cancer for a limited burden and at low cost.

This trial consists of 4 visits:

Visit 1 (V1, outpatient clinic):

Patients will be screened for inclusion in the study during follow up visits in the outpatient lung cancer clinic. If oncological check-up 6 months after starting initial lung cancer treatment demonstrates objective response (partial response or complete response defined by RECIST V1.1) the patient is asked to join the study. If the patient wants to join the study a screening visit (V2) will be planned.

Visit 2 (V2, screening visit (run-in)):

During V2 all eligible patients who have signed the informed consent will enter the run in epoch of 1 to 2 weeks.

Patients are asked about their medical history (baseline demographic data) and their previous respiratory treatment including their oncological stage and type. Co-morbidities will also be assessed and a basic lung function will be performed.

On V2 patient will receive a Dynaport movemonitor to wear one week before V3. For patients where the run in period is more than one week, they will receive a telephone reminder to wear a PROactive monitor. Patients are instructed to wear the device during waking hours. A measurement of more than 8 hours of wearing time will be defined as a 'valid day). The tri-axial accelerometer will captured steps waked per day, movement intensity and time spent in sitting, lying walking and high-intense activities.

Visit 3 (V3, baseline, allocation):

Patients will complete the web-based version of the clinical visit of the PROactive questionnaire. Two six-minutes walk tests will be performed and the patient will complete 2 quality of life questionnaires (SGRQ and QLQ-C30). During V3, the patients are divided into either control (usual care) or telecoaching group based on personal preferences and the abilities of using and having a smartphone.

Patients in both groups will receive a brochure during this visit explaining the importance of physical activity with recommendations to improve it. This brochure will be discussed together with the patients.

In the intervention group patients will recieve the telecoaching intervention consisting of the following components: 1: motivational interview with the investigator discussing motivation, barriers, favourite activities and strategies to become more active; 2: a pedometer giving direct feedback on the amount of steps; 3: the coaching application linked to the pedometer, which will be installed on the patient's smartphone and which will be coaching the patient for 8 weeks by means of improving the amount of steps per day. 4: telephone contact when a patient is non-compliant with either the use of the coaching intervention or with achieving the physical activity goals for 2 consecutive weeks.

All patients will be equipped with the Dynaport movemonitor one week before V4 and will be instructed to wear the monitor for 7 consecutive days.

Visit 4 (V4, end of the study, 8 weeks post allocation):

V4 is the end of the study. All assessments performed on V3 will be repeated during this study visit.

1. Patients diagnosed with stage III or stage IV NSCLC who have a documented disease control (stable disease, partial or complete response defined by RECIST V1.1) at least 6 months after start of first line treatment. Stage III patients can only be included, if first line treatment consisted of concurrent chemoradiotherapy and a consolidation immunotherapy if indicated (if PDL1 > 1% and no potential contraindications for immunotherapy). Stage IV patients, should have received only immunotherapy (PDL1 > 50%) or a treatment of at least 4 cycles of a platinum based chemotherapy with or without immunotherapy. Maintenance therapy with chemotherapy and/or immunotherapy and administration of local radiotherpy is allowed. Patients with objective response can be included in the study until 2 years after starting up initial treatment.
2. > 18 years
3. Patients who are able to engage in a remote coaching program through the use of a smartphone

Exclusion criteria:

1. Patients actively participating in a pulmonary rehabilitation program
2. Patients with sequential chemoradiotherapy for stadium III non-small cell lung cancer
3. The presence of orthopedic problems not allowing an increase in PA levels

No, because this is a pilot trail we are not going to share the data with other researchers.

Patients are evenly divided into the telecoaching group or usual care group according to owning a smartphone and their affinity with it.