Peptide radio receptor therapy (PRRT)

Peptide radioreceptor therapy (PRRT) is a systemic radioactive treatment that targets tumor cells expressing somatostatin receptors. The most commonly used tracer, Lu-177 DOTATATE, has been used for over a decade in treating advanced or metastatic neuroendocrine tumors (NETs).

Treatment can slow down the progression of neuroendocrine tumors and improve patients' quality of life. Many retrospective and prospective studies have shown high response rates and survival rates, and treatment has been proven to improve quality of life.

In Germany, this treatment is only carried out under inpatient conditions for radiation protection.

When is peptide radio-receptor therapy indicated?

The therapy is used in surgically incurable patients with primarily advanced metastatic neuroendocrine tumors.

Whether PRRT can help and whether it is the right approach should always be decided on an interdisciplinary basis with your endocrinologist and in a personal discussion between doctor and patient. Diagnostic examinations (68Ga-DOTATATE PET/CT) should show in advance whether the neuroendocrine tumor or metastasis has the desired characteristics and whether it accumulates sufficient radioactively labeled medication.

Aim of the therapy

• Partial to complete regression of the tumors
• Stable tumor behavior
• Improve quality of life
• Extend life expectancy

The Therapy

On the day of admission, you must not eat anything from 7 a.m. onwards. However, you should take your medication and have breakfast beforehand.
For treatment, the therapeutic substance will be administered to you slowly as an intravenous infusion over approx—30 minutes in the therapy ward.
To prevent kidney damage, intravenous amino acid infusions are administered immediately before, during, and following days after treatment.

Sufficient fluid intake on the day of treatment and the following days is also recommended, as this can reduce the radiation load on the kidneys and the rest of the body.

After treatment, whole-body scintigraphy images and blood samples are taken to monitor the storage of Lu-177 in the tumor cells and the degradation of the therapeutic agent.

You should ensure that you maintain the greatest possible distance from the therapy application to avoid exposing staff to unnecessary radiation.

Activity measurements are carried out in your room. A detector is installed in the ceiling above your bed for this purpose. We measure your total body activity in the morning.

During your stay, you are not allowed to leave the therapy ward or receive visitors.

There is an absolute smoking ban on the therapy ward. We recommend that you bring nicotine patches with you if necessary.

You can use your private clothing without hesitation. Before you are discharged, you will also receive recommendations on what to do in the first few days after discharge.

Possible side effects

Most patients tolerate the treatment well and have no serious side effects. The following side effects are possible but do not necessarily occur:

• Allergic reactions to the therapeutic substance
• Headaches
• Nausea, vomiting
• Tredness, fatigue
• Flushing symptoms
• Kidney damage to the point of requiring dialysis
• Bone marrow damage up to myelodysplastic syndrome

Aftercare

After discharge, laboratory checks (blood, liver, and kidney values) should be carried out weekly for the first four weeks and then at fortnightly intervals. The family doctor, endocrinologist, or oncologist can carry this out close to home.
Follow-up examinations (e.g., PET/CT, kidney scintigraphy) are carried out regularly to check the response to therapy, side effects, and complications. In the event of a good response or stabilization of the disease and continued good deposition in the Ga-68-DOTATATE PET/CT, further treatment cycles can usually be planned if the blood count and kidney function allow this.