Each year in France, nearly 59,000 new cases of breast cancer are diagnosed, and approximately 22,000 mastectomies are performed. Among these patients, 30% choose to undergo breast reconstruction. Breast cancer leads to numerous physical and psychological changes. The need to strengthen patient support around breast reconstruction has been highlighted, and it is one of the priorities of the national Ten-Year Cancer Control Strategy. The growing number of patients living after cancer makes the management of post-treatment sequelae essential.

The rate of reconstruction is increasing thanks to improvements in technique and better access to information. Among the available options, the latissimus dorsi (LD) flap has been a standard technique for immediate and delayed breast reconstruction for over 25 years. The LD technique offers several advantages: high reliability, feasibility even in irradiated thoraxes, low rates of postoperative complications, and satisfactory aesthetic outcomes. Its versatility and reliability have made it a cornerstone of breast surgery. However, this technique can lead to short- and long-term functional sequelae, which persist in 10% of patients. To reduce these side effects, an optimized version-the lipofilled mini-latissimus dorsi flap (mLD)-was developed by a team in Strasbourg. This quicker and less muscle-invasive technique is mainly used for immediate reconstruction or to replace implant-based reconstruction, with systematic lipofilling. However, no objective functional assessment of this method has yet been carried out, justifying a stratification according to the type of procedure for randomization in future studies. According to a prospective Icelandic study involving 15 patients, full recovery can be expected, but patients must be informed of the time and effort required to achieve it. The authors also concluded that further research is necessary to better understand the limits of long-term recovery.

A study of 450 LD reconstructions showed that pain and the main functional sequelae were located in the back and shoulder, with 10% of patients experiencing significant long-term pain. In addition, according to this study, around 40% of patients consider postoperative sequelae and scarring burdensome. However, regret rates remain low, at under 3%.

In view of these findings, preventing pain and functional impairment has become a key research focus to improve patients' quality of life.

Postoperative rehabilitation plays a crucial role in managing pain, reducing functional impairment, and optimizing aesthetic outcomes. The addition of mechanostimulation (MS) has been shown to improve scar appearance, shoulder function, and functional well-being compared with rehabilitation alone. MS is delivered using a device equipped with motorized rollers and suction to mobilize tissues. In physiotherapy, it helps relieve pain and improve mobility.

Prehabilitation, a rapidly expanding concept in surgery, aims to prepare patients before their procedure. However, to date, no prehabilitation approach combining physiotherapy and MS has been considered prior to LD flap surgery. One study highlighted improved tissue trophicity after tissue preparation with MS before lipomodelling.

The objective of our study is to evaluate the benefit of prehabilitation through physiotherapy incorporating MS to prepare tissues (in particular skin and muscle) on shoulder pain and functional outcomes in patients undergoing breast reconstruction with a latissimus dorsi flap.

Additionally, due to the heterogeneity and sometimes limited access to specialized postoperative physiotherapy, extensive patient follow-up has been planned in order to describe, on an exploratory basis, real-world rehabilitation practices.

Inclusion Criteria:

• Female patient aged 18 years or older
• Scheduled for breast reconstruction with a latissimus dorsi flap following breast cancer
• Patient has been informed and has signed the informed consent form
• Affiliated with a social security system

Exclusion Criteria:

• Patient with pre-existing shoulder pathology (Constant score < 80/100)
• Patient with uncontrolled psychiatric or mental disorders
• Patient unable to understand French

All data will be available after publication of the results in peer-reviewed revues, and in national and international meetings. It includes all de-identified participants' data, the study protocol, the statistical analysis plan and the clinical study report. The corresponding author will provide data and datasets generated and/or analyzed during the study upon reasonable request.

Access to study data upon written detailed request sent to ICM, from 6 months until 5 years after publication of summary data.

The data shared will be limit to that required for independent mandated verification of the published results, the applicant will need authorization from ICM for personal access, and data will only be transferred after signing of a data access agreement.