The purpose of this study is to examine the different outcomes of breast reconstruction in women who are treated for breast cancer with mastectomy and subsequently have delayed breast reconstruction by one of two different surgical techniques both of which are based on the use of a tissue flap from the patient's back. These techniques are either a latissimus dorsi flap (LD-flap) or a thoracodorsal artery perforator flap (TAP-flap)

The main objective of the study is to establish whether one of these techniques may result in a superior outcome and thus should be recommended as first choice treatment rather than the other.

Women, who are treated for breast cancer with mastectomy, are usually eligible for subsequent reconstruction of the breast. Depending on various conditions the reconstruction can be either immediate or delayed.

Several different surgical techniques for delayed breast reconstruction have been described. An important factor that applies to delayed reconstruction is the lack of excessive, healthy skin in the area where the breast has been removed and the purpose of the surgical techniques developed for this are therefore to provide sufficient amounts of skin and/or other tissues to recreate the contour of the breast. The methods for this can broadly be classified as either expander/implant based or autologous-tissue based. Though full autologous reconstruction is preferred by many surgeons and patients due to the superior result this is not always possible why an implant can be needed in combination with the tissue flap to provide sufficient volume.

In the irradiated patient simple expansion of the skin if often impossible and transfer of autologous tissue is normally required. A wide armamentarium of different methods are available utilizing either pedicled or free flaps for tissue transfer. The most widely used techniques for this in general are reconstruction with abdominal flaps . However, when these women are not eligible for either reconstruction with an abdominal flap or microsurgical reconstruction with other free flaps a well-known and much used technique for reconstruction is the Latissimus Dorsi-flap (LD-flap).

Using this method an island of skin and subcutaneous tissue is provided from the upper part of the patient's back with blood supply deriving from the two main branches of the thoracodorsal artery, which are imbedded in the underlying Latissimus Dorsi muscle. A so called musculocutaneous tissue-flap is raised from the patient's back and tunnelled to the front of the thorax carrying the entire Latissimus Dorsi muscle and the paddle of overlying skin. At the front of the chest the muscle is usually used to drape a silicone implant, and the skin is used to recreate the breast mound. This method is very well-described in the literature, offers a safe and reliable option for breast reconstruction and is often used for this purpose.

Donor site sequelae are however debated. A direct consequence of transferring the Latissimus Dorsi muscle during the procedure is loss of the muscles function in the shoulder and upper arm which involves extension, adduction and rotation of the shoulder joint. Partial impairment in the form of reduced strength and/or restricted movement is thus to be expected as is pain and weakness in the neck, shoulder and upper arm. Other muscles can replace the lost function of the Latissimus Dorsi, and with sufficient rehabilitation and training patients are expected to regain normal function over time. Long term sequelae in the form of chronic pain, discomfort, weakness and/or restricted range of motion have been described but the evidence on this particular area are ambiguous. There are no systematic reviews of the evidence in the published literature and most papers comprise case reports and retrospective cohort studies although a few prospective studies also exist. The different papers indicate varying rates of long-term morbidity associated with the shoulder and arm but the risk of some impairment and chronic pain cannot be ignored based on the available evidence.

At Vejle Hospital in Denmark, we have adopted a new technique for total breast reconstruction as an alternative to the LD-flap in July 2011. This method makes use of a fasciocutaneous flap, which is also raised from the patient's back. Although the blood supply also derives from the Thoracodorsal artery imbedded in the Latissimus Dorsi muscle the flap only contains skin and subcutaneous tissue. The perfusion of blood is instead supplied through a perforator artery, normally arising from the descending branch of the main vessel. This flap is called a Thoracodorsal Artery Perforator-flap (TAP-flap/TDAP-flap) and was first described in the literature in 1995 .

Use of the TAP flap as a pedicled perforator flap have been described in several cases aiding in the treatment of defects on the trunk, upper extremity, head and neck. In the field of breast surgery it has primarily been used for oncoplastic procedures, although a few papers describe the preliminary use of the TAP-flap in combination with an implant for total reconstruction of a breast. As this technique was only recently adopted none of the published studies examine the long term results nor the advantages of using the TAP-flap. A single retrospective study investigates shoulder function after harvest of the flap and finds no affection of the shoulder joint or the upper arm .

We have chosen to perform a modified version of the technique combining the TAP-flap and implant with the use of an acellular dermal matrix (ADM). This matrix is used to drape the lower pole of the implant and in a sense creates an internal bra that supports the prosthesis. We presume that this in part replaces the supportive effect that is normally provided by the muscle when using the LD-flap. The ADM is thus used as a substitute for the patient's own tissue and will over time become integrated as a part of it.

Applying this technique the upper part of the silicone implant is covered by the Major Pectoral muscle, while the lower part is draped by the ADM. The matrix is sutured to the free, lower edge of the muscle as well as to the chest wall at the desired level of the new inframammary fold. This covers and fixates the implant relieving pressure on the flap which is afterwards used to cover the reconstructed mound. We believe this enhances sufficient blood supply to the flap and thus provides the most optimal conditions in terms of obtaining complication-free healing.

Harvest of the TAP-flap allows the Latissimus Dorsi muscle to be left undissected in most cases. When indicated a small cuff of muscle surrounding the dominating perforator can be included in the flap or a small back cut inferiorly to the perforator can be made to allow tension free rotation of the skin paddle. In all cases the procedure is expected to leave the muscle function intact.

Though the TAP flap is well-described for several reconstructive purposes application of the flap as a tool for total breast reconstruction is a new endeavour and its importance has not yet been established. Based on the flaps properties and the more gentle dissection/harvest of the tissue which leaves the underlying Latissimus Dorsi muscle intact we presume the application of this new technique to facilitate a statistically significant reduction in the associated morbidity in terms of impairment and/or chronic pain in the shoulder, back and upper arm which can been experienced after LD-flap based reconstruction.

Furthermore we expect the use of the TAP-flap to cause a decrease in the need for postoperative physical rehabilitation in terms of physiotherapy and training. The aim of this study is thus to test whether this hypothesis is true in order to establish whether the TAP-flap based reconstruction offers any advantages should be favoured above the conventional LD-based reconstruction.

The main objective of this study is to determine whether any detectable difference in shoulder affection distinguishes these two techniques. For this purpose we have designed two separate trials:

Retrospective Follow-up Trial This part of the study intends to examine and compare historical data on women who have already had a delayed breast reconstruction by one of the two methods. The main goal of this pilot study is to collect and analyse all existing information in order to provide a sound background knowledge that should serve as basis for the following RCT. Most importantly this study should provide sufficient data to perform an accurate calculation of the sample size.

Randomized Clinical Trial This trial will be conducted as a confirmatory superiority trial. The intend is to collect, examine and compare data on the two surgical techniques in order to test superiority of the TAP-flap based reconstruction in accordance with our hypothesis as specified above.

The trial is thus designed with two parallel study-arms as patients are allocated to reconstruction by either LD-flap or TAP-flap in the ratio 1:1. As the clinically most important parameter seems to be any objective change in shoulder function this will serve as the primary end-point. Patient reported discomfort/pain as well as the need for physical rehabilitation will also be investigated and analysed as supportive secondary end-points.

In addition to the above data on a number of other patient-related outcomes will be collected as part of this trial. These issues will be addressed as tertiary end-points of a more exploratory nature. We expect these data to supply useful knowledge for further investigations in separate studies.

Designed as multicentre trial patient enrolment and all collection of data will be performed at academic hospitals in Denmark and Norway. All Danish units specializing in plastic and reconstructive surgery who are familiar with both techniques used in this protocol have been invited to participate in this trial. In addition one centre in Skien, Norway, who adopted the TAP-flap technique prior to the initiation of the trial, was invited to participate.

To avoid bias relating to the possible effect on the outcome measures caused by other surgical procedures such as mastectomy and axillary surgery performed simultaneously with the reconstruction only delayed procedures will be studied, as these are also most commonly the cases where autologous tissue transfer is required.

A password protected, electronic database placed on a secure server will be established. This database will only be accessible to the primary investigator and members of the research group who will be involved in the analysis of data. Data are not blinded in relation to allocated treatment.

This study will provide a better knowledge of the expected outcome of delayed breast reconstruction, when it is performed by one of these two surgical techniques. Thus the investigators expect that these results will help determine if the TAP-flap in combination with ADM may represent a better and gentler method for reconstruction of the breast with lower morbidity and better cost-effectiveness than the conventional LD-flap. In all cases the results of this trial will enable us to provide patients with better and more objective information, before they are subjected to delayed breast reconstruction.

To avoid bias relating to the possible effect on the outcome measures caused by other surgical procedures such as mastectomy and axillary surgery performed simultaneously with the reconstruction only delayed procedures will be studied, as these are also most commonly the cases where autologous tissue transfer is required.

Patients that should thus be assessed for eligibility will include all women referred to the participating centres for unilateral, delayed breast reconstruction in the inclusion period. The criteria for participation are as follows:

Inclusion criteria:

1) Women over 18 years of age who are referred in the period between 1st of September 2013 and 30st of August 2015 for the purpose of unilateral, delayed breast reconstruction, and who are found best suited for reconstruction with a pedicled tissue flap from the back.

Exclusion criteria

1. Patients found better suited for reconstruction by another method i.e. abdominal or free flap-reconstruction or expander/implant-based reconstruction.
2. Patients with severe dementia that makes it impossible to collect data or obtain informed consent
3. Non-Danish speaking patients from whom informed consent cannot be obtained by interpreter
4. Patients where a suited perforator of the Thoracodorsal artery cannot be identified by colour Doppler ultrasonography.

All women referred for delayed breast reconstruction in the inclusion period will be assessed for eligibility and those meeting the criteria of the study population will be invited to participate in the study. The assessment will be conducted at the preliminary examination in the outpatient clinic by one of the centres consultants assigned to the trial.

Invited patients will receive both oral and written participant information after which a period of minimum 14 days is required before the patient can be enrolled in the trial in accordance with the The Danish Health Act.

Patients considering participation will be invited for a second consultation where written informed consent will be obtained from all who accept the invitation. Randomization will be performed immediately afterwards allocating the patient to reconstruction by either the LD-flap or the TAP-flap. Patients who do not which to be enrolled in the trial will be offered reconstruction with the LD-flap as this must be considered standard of care.