Rationale: Flap fixation significantly reduces the incidence of seroma formation after mastectomy. Therefore, research should focus on finding the most optimal way to secure the skin flaps to the pectoral muscle. Previous studies have compared running sutures, interrupted sutures and tissue glue application to conventional wound closure. A recent systematic review with network meta-analysis indicated running sutures as the most optimal technique, however direct comparisons and high quality articles were lacking.

Objective: This prospective trial aims to directly compare running sutures with interrupted sutures in order to prevent complications in patients undergoing a mastectomy.

Study design: This trial will combine a retrospective cohort from the previous SARA-trial in Zuyderland MC with a randomised prospective trial. This study design was chosen to acquire a sample size with sufficient power and the ability to conduct this study in an acceptable time frame.

Study population: A retrospective cohort of patients participating in the SARA trial (RCT) and a prospective cohort of patients undergoing a mastectomy for breast cancer.

Intervention: Group 1: Flap fixation after mastectomy with running sutures. Group 2: Flap fixation after mastectomy with interrupted sutures.

Main study parameters/endpoints: The primary endpoint is the incidence of complications requiring interventions in both groups, including clinically significant seroma, infections and bleeding complications. Secondarily, the length of the procedure and cosmetic results will be compared.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: When participating, patients will undergo 3 additional outpatient clinic visits. Study visits will be combined with regular visits where possible, including the first postoperative visit after 7-10 days and either the 6 week or 3 month visit.

Inclusion Criteria:

• Female sex.
• 18 years or older.
• Indication for mastectomy.

Exclusion Criteria:

• Patients undergoing breast conserving therapy
• Patients undergoing direct breast reconstruction
• Patients undergoing modified radical mastectomy
• Unable to comprehend implications and extent of study and sign for informed consent