This study aims to assess the acceptability, feasibility, and preliminary efficacy of an e-Health psychological intervention specifically designed to promote sexual health, mental health, and general well-being and quality of life in men with prostate cancer. A pilot study will be conducted involving prostate cancer survivors randomly assigned to one of two conditions: the experimental group (receiving the program) vs the control condition (waiting list). The experimental group is expected to improve on outcomes related to mental and sexual well-being when compared to the control group. Furthermore, the experimental group is expected to show good acceptability of the intervention program. This study aims to inform the design and methodology to be adopted in a future randomized controlled trial aimed to further test the e-Health intervention's efficacy.

This study was approved by the Ethical Board of São João Hospital, Porto. An online psychological intervention (e-Health app technology) specifically tailored to meet the needs of Portuguese men with prostate cancer was developed to promote participants' mental and sexual health. The intervention protocol was designed under Cognitive-Behavior Therapy (CBT) principles, featuring psychological and sexual health promotion strategies. The intervention program consists of 5 modules covering components of psychoeducation, sexual rehabilitation, mindfulness, cognitive restructuring, and relapse prevention. The modules will be delivered online (using text, videos, and graphics) along with therapeutic guidance and support provided by a certified Clinical Psychologist over six weeks.

Participants will be recruited at cancer units and will meet the inclusion criteria: prostate cancer survivors; 18 years old or older; ability to give informed consent; regular use of a smartphone and internet access; no other oncological diagnoses over the past five years, no severe neurological or psychological disorders. Participants will be randomly assigned to one of two conditions: 1) e-Health psychological intervention (N = 20); 2) waiting list group, N = 20). Participants will be clinically assessed before and after intervention on different psychosexual dimensions (e.g., mental health, quality of life, sexual dysfunction). By the end of the study, the waiting list group participants will be allowed to access the e-Health psychological intervention. The experimental group is expected to improve regarding mental and sexual well-being outcomes compared to the control group. Furthermore, the experimental group is expected to show the program's acceptability. This study aims to inform a future a randomized control trial that aims to further test the e-Health intervention's efficacy. Pre, post-test, and 3-month follow-up assessments will be performed.

Main outcomes: psychological distress, sexual distress, sexual satisfaction, relational satisfaction, sexual dysfunctional beliefs, and quality of life. All scales are validated and adapted to the Portuguese population. Furthermore, a semi-structured interview will be conducted with experimental group participants by the end of the study to collect user feedback.

Participants' data will be stored in an encrypted file, saved on a computer, and only accessible to the main researchers of this study. Confidentiality will be guaranteed by attributing an individual code to each participant. This code will be used to log into the digital intervention and complete psychometric scales. Interviews will be recorded and transcribed. Transcriptions will be marked with the same code to ensure the association of the collected data.

Statistical procedures will be performed using IBM SPSS and include i) descriptive analyses; ii) MANOVA to measure differences among groups and to compare assessment moments; iii) thematic analysis to understand the user's experience (post-intervention interview)

Inclusion Criteria:

• Prostate cancer survivors,
• 18 years old or older,
• Ability to give informed consent,
• Regular use of a smartphone and internet access.

Exclusion Criteria:

• Other diagnosed oncological diseases over the past five years,
• Severe neurological impairment or other severe psychological/psychiatric diseases (depression, generalized anxiety disorder, psychosis-related disorders),
• Other uncontrolled/unstable diseases,
• Severe hearing and/or visual impairment,
• Under psychotherapy or treatment for sexual problems,
• Participating concurrently in other clinical trials.