Lutetium treatment is a peptide receptor isotope treatment where lutetium isotope (lu-PSMA) is the radiating substance. The treatment is suitable mainly with tumours that are found to contain somatostatin receptors. The method is typically used to treat metastasized neuroendocrine tumours (e.g. GEP-NET) in the intestines, for example (“carcinoid tumours”). These tumours are relatively rare.
During the treatment, the radiopharmaceutical is given as an infusion and, at the same time, the patient is given a nephroprotective dose of amino acid solution and/or plasma expander.
After the infusion, the radiation dose in the tumour and in the organs is determined with the help of SPECT-CT imaging. After the radiopharmaceutical infusion, the isotope distribution is tracked with multiple imaging sessions, sometimes up to one week after the treatment.
The technique is so demanding that peptide receptor treatments have been centralised to a few centres worldwide. Until now, Finnish patients have been treated abroad, mainly in Uppsala. Docrates Cancer Center started regular lutetium treatments in the spring of 2010.
Lutetium has a powerful destructive effect on the tumour cells, but its range is short, only 2 millimetres. For this reason, the treatment series consist of four sessions every 8–10 weeks. In some cases the treatment may be curative, but it is also used to control cancer symptoms.
Lutetium treatment can be combined with drug and radiation therapies. The isotope yttrium-90 can be used in peptide receptor treatment, which has a longer range than lutetium, up to 11 mm, and a shorter half-life. Yttrium-90 is not as radioactive as lu-PSMA, but its range is broader. Yttrium-90 also radiates less into the environment than lu-PSMA. Neither treatment poses a danger to the environment due to the radiation levels. The day following the treatment is spent in the hospital.
Yttrium treatments are given in series of two treatments every 8–12 weeks. The isotope treatments are planned on the basis of the diagnosis and the dose calculation measurements or, in other words, based on SPECT-CT imaging.
Lutetium in the treatment of metastatic prostate cancer
In January 2017 our hospital became the first in Finland to introduce cancer treatments with the new lu-PSMA radiopharmaceutical. The treatment enables effective destruction of prostate cancer metastases outside the skeleton without any major adverse effects.
The radiopharmaceutical lu-PSMA is able to bind to PSMA molecules found on the cell surface of prostate cancer cells regardless of their location. The radiation source can thus be directed directly into the cancer cells or their immediate vicinity. A PET-CT examination with Gallium-68-PSMA tracer is required prior to the treatment in order to make sure that the metastases react to lu-PSMA.
Lu-PSMA treatment is administered intravenously and its most common side effect is dryness in mouth. The treatments are given in line with the patient’s individual treatment plan, generally 2-6 times every 4-6 weeks.
A multi-professional team, led by nuclear medicine docent and specialist Kalervi Kairemo, is in charge of peptide receptor treatment at Docrates Cancer Center.