Treatment

If the tumour grows, the first option is almost always drug treatment to slow down the growth.

Tamoxifen works anti-oestrogen which means that the drug prevents oestrogen (sex hormone) from binding to tissues. If a tumour is 'oestrogen-sensitive' and therefore grows harder due to oestrogen, this drug can inhibit the tumour's growth. Some desmoid tumours are hormone-sensitive. Any results may be seen only after several months of treatment. Hormone therapy can be combined with an NSAID.

In practice, there is no strong scientific rationale for this type of treatment. However, it is still frequently used in practice, mainly because of the rather limited side effects and the easy availability of the medication.

Meloxicam and celecoxib belong to the group of drugs called NSAIDs. Due to the mild side effects of this drug, it is used as first-choice treatment, possibly in combination with hormone therapy, in desmoid patients.

Targeted therapy (targeted therapy) is the treatment with drugs that act on specific points in the cell, influencing its division. Drugs that fall under this group are: imatinib, sorafenib, sunitinib and pazopanib.

Imatinib is the first form of target therapy tested in desmoid tumours. A lot of studies have been done on the use of imatinib in desmoid patients. As a result, it has become a well-known drug whose (mild) side effects are also well known. The therapeutic effect of imatinib is rather limited.

Meanwhile, a phase 3 study has also been conducted with Sorafenib. This study showed very positive results. The main side effects are fatigue, gastrointestinal symptoms and skin reaction. Unfortunately, this medication has not yet been reimbursed for desmoid tumours.

Sunitib and pazopanib also belong to the same class of target therapy and are sometimes used in desmoid tumours.

The problem with this form of therapy remains reimbursement. Indeed, many of these drugs are not registered as treatments for desmoid tumours.

Systemic therapy is a treatment that acts on the entire body, usually referred to as chemotherapy. The aim of systemic therapy is to attempt to make the desmoid tumour (partially) die or shrink. Chemotherapy is used in inoperable or rapidly growing tumours or life-threatening desmoid tumours.

Chemotherapy regimens used in desmoid are:

This combination of drugs has been studied especially in young patients with aggressive desmoid tumours. This showed that it can be an effective treatment in many patients. The treatment must be given for at least a year before results become visible. This combination chemotherapy has many side effects and a long treatment duration, which can make it perceived by patients as a heavy treatment.

Doxorubin is nowadays packaged in 'fat globules' and therefore called 'pegylated liposomal doxorubin (Caelix)'. Because it is packaged in a specific way, patients experience fewer side effects from the drug than from pure doxorubin. This chemo is known to be less harmful to healthy tissues and faster results are seen.

The indications for surgery for desmoid tumours have changed significantly over time. Today, surgery is no longer part of first-line treatment. This is because a desmoid tumour can also stop growing spontaneously without the need for treatment. In addition, the tumour often returns after surgery. The decision to operate on the tumour anyway is made in a multidisciplinary consultation. This takes into account the location of the tumour and surrounding tissues that may be damaged during surgery.

The size of the tumour in itself is certainly not a reason to operate. Only in specific cases is there nevertheless an indication to opt for surgery as initial treatment instead of a wait-and-see policy. This applies to patients who do an acute complication such as an intestinal perforation or if tumour growth does not allow sufficient blood flow to certain organs/body parts. In addition, cosmetic reasons or a tumour that grows close to critical structures and could therefore lead to fatal consequences with minimal growth may be an indication for surgery.

 In some cases, a biopsy is not possible because of the location of the tumour. In these cases, surgery is the only option to confirm the presence of a desmoid tumour.

 As mentioned earlier, this tumour grows with fine tentacles in the surrounding muscles, tendons and subcutaneous tissue. To prevent the tumour from recurring, these tentacles must also be removed with it. However, the surgeon cannot see these fine tentacles during surgery, and has to decide based on the MRI images which muscles and such should be removed. If the impact on your function is not too great, a generous margin of healthy tissue can be taken away along with it to make sure all tentacles are gone. Muscles or tendons that are removed do not grow back, even in children. The surgeon can reposition other muscles to allow you to move maximally, but a full recovery is not always possible. Very exceptionally, part of the bone has to be removed if the desmoid tumour grows against the bone. This bone should then also be replaced or repaired to prevent a fracture.

 Since a desmoid tumour is a benign tumour, the surgeon will always try to weigh the impact of removing healthy tissue against the need to remove the tumour completely. The surgeon will always discuss with you what is needed in theory and how far you want to go. If, after removal, remnants of the tumour remain, it may be necessary to subsequently irradiate the area where the tumour was located. This is done mainly in areas where it would be difficult to remove the tumour again if it returned, for example around the nerves of the neck.

Radiation is a form of treatment that acts locally on remnants of the desmoid tumour.

The role for radiotherapy in desmoid tumours is getting smaller and smaller. However, radiotherapy can still be used in well-selected cases. Studies show that radiotherapy can promote local control after surgery and thus prevent relapse. Radiotherapy may also be indicated for some patients with non-operable tumours (e.g. in the head and neck region). The first effect of radiotherapy is usually not seen until several months later.

High doses of radiotherapy are needed to treat a desmoid tumour (50 - 60 Gy), you should count around 5-6 weeks of treatment, 5 times a week. The aim of radiotherapy is to reduce the likelihood of the tumour returning locally. This treatment also has side effects, notably fatigue, local discolouration and hardening of the skin, shortening of muscles and stiffness of joints. Sometimes lymphoedema may also occur.

Translated: 'regional isolated perfusion'

In this treatment, a drug is administered in high doses into one of the limbs without reaching the rest of the body.

This treatment can be given for tumours in the limbs (legs or arms) and takes place under anaesthesia. For 60-90 minutes, a combination of two drugs in high doses is passed through the blood vessels of the affected body part - arm/leg. The body is largely protected, as the drugs do not reach the entire body.

Effect: freezing of the tumour

Under local anaesthesia and with the help of imaging such as a CT, needles are inserted into the tumour. These needles reach an extremely low temperature, freezing the tumour. Cryoablation is not used in all centres and is mainly used for smaller extra-abdominal tumours.

Mode of action: heating the tumour

Ultrasonic waves (also used in ultrasound) are bundled in such a way that they collide into the tumour, sparing the healthy tissue. The collision creates localised heat that affects the tumour. For now, this treatment is only performed in study settings, abroad.