Gamma probe-assisted lymph node removal

Prostate cancer metastases in neighbouring lymph nodes are often so small that they cannot be reliably identified using conventional imaging methods such as MRI or CT scans. New methods enable surgeons to identify even small metastases and lymph nodes containing cancer cells more effectively than ever before – and then treat them successfully. This treatment uses a contrast agent that is otherwise harmless to humans and accumulates in tumour tissue, thereby providing radioactive labelling of metastases.

A contrast agent makes the tumour cells visible

PSMA-PET imaging makes use of Prostate-Specific Membrane Antigen (PSMA), a protein that can be found frequently on the surfaces of prostate cancer cells. The contrast agent is a radioligand that binds to the PSMA and acts as a radioactive label on prostate cancer cells. Positron emission tomography (PET) visualises metastases that are emitting radiation. This enables the surgeon to determine the precise location and size of the malignant tissue and optimise their surgical plans accordingly. 

Who is a candidate for radioguided surgery?

In our experience, patients with the following characteristics are most suitable for this surgery:

• Good general health, minimal comorbidities
• Long remaining life expectancy 
• Findings isolated (as far as possible) in the pelvic region through PSMA-PET/CT
• Smallest possible increase in PSA level (ideally <2 ng/ml)

However, it is always important to obtain extensive advice by discussing the advantages and disadvantages before deciding on such a procedure, taking into account the patient’s individual circumstances and up-to-date PSMA-PET imaging.   

Summary

This method has been developed recently and its therapeutic potential has yet to be demonstrated conclusively. However, initial studies have shown that patients treated with this method can benefit from lasting reductions in their PSA level. In addition, many patients get by without the need for further treatment for an extended period after the surgery.

If the cancer returns and these metastases are removed at an early stage, this can postpone the need for hormone therapy or radiotherapy. In some cases, it can eliminate the need for follow-up treatment altogether, which is an immense relief for the patients in question. However, this treatment method for recurrent prostate carcinoma is currently still considered experimental and is not included in official guidelines. Although the initial results are very promising, we do not yet have long-term oncological data for PSMA-PET or PSMA-radioguided surgery.