Lung cancer and colorectal cancer accounted for the highest number of cancer deceases in 2016. Incidence is around 3.500 cases per year and patients are more commonly men (56%) aged around 69. This study focuses on people with a recent diagnosis of cancer who have been scheduled for surgery.

Evidence suggests that around 11% of people with cancer suffer from anxiety or adjustment disorders and 6,5% hold a diagnosis of major depressive disorder. Moreover, the perioperative period is the most distressing phase of the illness. However, a high number of patients do not have access to mental health services due to either limited resources and geographical limitations or the fear of being stigmatized. The aim is to explore the effectiveness of a mindfulness-based intervention for smartphones designed to reduce pre-surgical distress. It was conceived as a medical tool of prevention), with the purpose of diminishing emotional suffering and clinical complications after surgery. In 2020 Internet will be the most developed technology and almost everyone will have a smartphone; hence, an app for stress reduction will fit in this growing field.

Mindfulness is defined as the ability to pay attention to the present moment with a curious, non-judgmental attitude. Its training consists of both formal meditation practices and informal daily exercises. Mindfulness-based interventions are growing in our National Health System and rigorous researches are being conducted exhibiting good results regarding its effectiveness. However, the fact that Mindfulness instructors must be highly qualified makes these kinds of interventions exceedingly costly to implement. This team is experienced with mindfulness and has developed the app "En Calma en el Quirófano" ("Staying Calm in the OR") to reduce distress before surgery. It consists of a free, accessible, on-demand, short training through a series of guided meditation practices.

In this randomized controlled trial, participants are assigned either to the experimental ("Staying Calm in the OR") or the control arm (treatment as usual). The investigators expect anxiety and depression to be lower in the experimental arm; in addition, the researchers expect that "Staying Calm in the OR" participants will show higher levels of post-surgery recovery.

Lung cancer and colorectal cancer accounted for the highest number of cancer deceases in 2016. Incidence is around 3.500 cases per year and patients are more commonly men (56%) aged around 69. This study focuses on people with a recent diagnosis of cancer who have been scheduled for surgery.

Evidence suggests that around 11% of people with cancer suffer from anxiety or adjustment disorders and 6,5% hold a diagnosis of major depressive disorder. Moreover, the perioperative period is the most distressing phase of the illness. However, a high number of patients do not have access to mental health services due to either limited resources and geographical limitations or the fear of being stigmatized. The aim is to explore the effectiveness of a mindfulness-based intervention for smartphones designed to reduce pre-surgical distress. It was conceived as a medical tool of prevention), with the purpose of diminishing emotional suffering and clinical complications after surgery. In 2020 Internet will be the most developed technology and almost everyone will have a smartphone; hence, an app for stress reduction will fit in this growing field.

Mindfulness is defined as the ability to pay attention to the present moment with a curious, non-judgmental attitude. Its training consists of both formal meditation practices and informal daily exercises. Mindfulness-based interventions are growing in our National Health System and rigorous researches are being conducted exhibiting good results regarding its effectiveness. However, the fact that Mindfulness instructors must be highly qualified makes these kinds of interventions exceedingly costly to implement. This team is experienced with mindfulness and has developed the app "En Calma en el Quirófano" ("Staying Calm in the OR") to reduce distress before surgery. It consists of a free, accessible, on-demand, short training through a series of guided meditation practices.

In this randomized controlled trial, participants are assigned either to the experimental ("Staying Calm in the OR") or the control arm (treatment as usual). The investigators expect anxiety and depression to be lower in the experimental arm; in addition, the researchers expect that EnCalma participants will show higher levels of post-surgery recovery.

Main hypothesis. Anxiety and depression symptoms will be significantly lower in the experimental arm after Staying Calm in the OR" training.

Secondary hypotheses. Recovery after surgery will be higher amongst participants in the experimental arm, who will exhibit fewer post-surgical complications, lower rates of hospitalizations, lower levels of analgesia, shorter hospitalizations and a better quality of life.

Inclusion Criteria:

• 18 - 100 years old
• Diagnosis of cancer
• Being in waitlist for surgery for less than 14 days
• Signed informed consent

Exclusion Criteria:

• Acute severe mental disorder according to DSM-5 diagnostic criteria
• Not having a smartphone
• Not being able to download and use the smartphone app "Calm before Surgery"

Data will be shared with other researchers on request

Data will be available one year after publishing the final results for at least 5 years

Please contact PI Beatriz Rodríguez-Vega (beatrizrvega@gmail.com)

Principal investigator randomize the participants. Two psychologists who do not know the allocation perform the assessments, mostly through self-reported instruments. Another investigator analyze the outcomes.