This study aims to evaluate the feasibility and potential benefits of music therapy in patients with breast cancer undergoing adjuvant chemotherapy.

Breast cancer patients often experience significant physical and psychological symptoms during treatment, including anxiety, fatigue and reduced quality of life. Music therapy is a promising non-pharmacological intervention that may help improve psychological well-being and symptom management. However, current evidence is mainly based on group-level studies and does not account for individual variability in response.

This pilot study is designed as a series of combined N-of-1 trials, in which each participant alternates periods with and without music therapy, acting as her own control. A total of 24 patients will be recruited from two Italian oncology centres and randomly assigned to different intervention sequences.

The intervention consists of weekly group music therapy sessions lasting approximately 60 minutes, including both active and receptive techniques, along with personalized music playlists for home use.

The primary objective is to assess the feasibility of this study design, including recruitment, retention, data completeness and acceptability of the intervention. Secondary objectives include exploring the effects of music therapy on psychological and physical well-being, as well as estimating variability in individual responses.

The results of this study will inform the design of future larger studies aimed at evaluating the effectiveness of music therapy using personalised trial approaches.

Breast cancer is the most commonly diagnosed cancer among women worldwide and is frequently associated with a substantial burden of physical and psychological symptoms during treatment. Patients undergoing adjuvant chemotherapy often experience anxiety, fatigue, sleep disturbances and reduced quality of life, which may negatively affect treatment adherence and overall well-being. Addressing these multidimensional needs requires integrated, patient-centred supportive care approaches.

Music therapy (MT) is a clinical and evidence-based intervention delivered by trained therapists, using both active and receptive techniques to support psychological and emotional well-being. Previous studies have shown that MT may reduce anxiety and improve mood and quality of life in oncology settings. However, most available evidence is based on conventional group-level study designs, which do not adequately capture the variability in individual responses to the intervention.

N-of-1 trials represent an innovative methodological approach in which repeated treatment and control periods are compared within the same individual, allowing each patient to act as her own control. This design enables the evaluation of personalised treatment effects and intra-individual variability, which is particularly relevant for supportive care interventions such as music therapy.

This study is a multicentre, non-profit, interventional pilot study designed as a series of combined N-of-1 trials. A total of 24 patients with histologically confirmed breast cancer undergoing adjuvant chemotherapy will be recruited from two oncology centres in Italy. Participants will be randomly assigned to one of two intervention sequences, alternating periods with music therapy and periods without intervention according to a crossover design consisting of four consecutive phases (A-1, B-1, A-2, B-2), each lasting four weeks.

During intervention phases, participants will attend weekly group music therapy sessions lasting approximately 60 minutes. Sessions will include both receptive techniques (such as guided listening and music imagery) and active techniques (such as instrumental or vocal improvisation and songwriting). In addition, participants will receive personalised music playlists to be used between sessions.

Assessments will be conducted at baseline and at predefined follow-up time points throughout the study (T1, T2 and T3), as well as before and after MT sessions where applicable. Patient-reported outcome measures will include validated instruments assessing anxiety, depression, quality of life, emotional distress, symptom intensity and sleep quality.

The primary objective of the study is to assess the feasibility of conducting an N-of-1 trial design in this population, including recruitment, retention, data completeness and acceptability of the intervention. Secondary objectives include exploring changes in psychological and physical well-being and estimating intra- and inter-patient variability in treatment response.

As a pilot study, this trial is not powered to detect definitive treatment effects. The results will be used to inform the design, methodological assumptions and sample size calculation of future adequately powered studies evaluating the effectiveness of music therapy using personalised trial approaches.

Inclusion Criteria:

Participants will be eligible for inclusion if they meet all of the following criteria: - women age 25-75 years;

• histologically confirmed diagnosis of BC;
• undergoing adjuvant chemotherapy following surgery;
• Eastern Cooperative Oncology Group (ECOG) performance status of 0-1;
• ability to understand the Italian language and comply with study procedures;
• provide written informed consent to study participation.

Exclusion Criteria:

Participants will be excluded if they meet any of the following criteria:

• active neurological disorders;
• active psychiatric disorders;
• current or past substance abuse;
• significant uncorrected visual, auditory or speech impairments;
• have primary or metastatic brain tumours, as confirmed clinically or radiologically;
• any condition that, in the opinion of the investigators, may interfere with participation in the study.

Due to the nature of the study