Unilateral or bilateral removal of pelvic lymph nodes in cases of early recurrence of prostate cancer following prostatectomy

Prostate cancer (prostate carcinoma) is a malignant disease of the prostate gland in which cells in the glandular tissue multiply uncontrollably. It can spread through the lymphatic system, with the pelvic lymph nodes often being the first site of metastases. If the cancer still responds to anti-hormone therapy, which deprives the body of the male sex hormone testosterone, it is considered hormone-sensitive (hormone-sensitive). Following surgical removal of the prostate (radical prostatectomy), a renewed rise in prostate-specific antigen (PSA) is usually the first sign of a relapse (biochemical recurrence). The rise in PSA levels may be detectable on imaging before cancer metastases appear. Among the new imaging techniques is PSMA-PET (prostate-specific membrane antigen positron emission tomography). PSMA is a protein on the surface of prostate cells that is particularly abundant on most prostate cancer cells. In PSMA-PET, a small amount of a radioactively labeled substance is administered intravenously. This substance binds to PSMA, thereby making the cancer cells visible. This works even when PSA levels are very low. In cases of recurrence confined to the pelvis, localized treatments are increasingly being considered, such as radiation therapy to the lymphatic drainage pathways or surgical removal of the pelvic lymph nodes (salvage lymphadenectomy). The goal is to delay the progression of the disease and postpone the need for long-term drug therapy. To date, lymph nodes on both sides of the pelvis are typically removed, even if imaging shows abnormalities on only one side. However, the surgery can lead to impaired lymphatic drainage, leg swelling, or lymphoedema. Lymphoedema refers to accumulations of lymph fluid that can form in the pelvis following lymph node removal. The aim of this study is to compare the treatment outcomes of unilateral and bilateral lymph node removal in cases of lymph node involvement on one side of the pelvis. Patients are randomly assigned to two parallel treatment groups. In one group, lymph nodes are removed only on the affected side; in the other, the corresponding regions on the opposite side are also removed. In both groups, the surgery is performed either as open surgery or robot-assisted surgery. The study is blinded, which means that the physicians performing the histological examination of the removed lymph nodes do not know which group the patients belong to. The patients themselves are informed of the outcome of the random assignment; those who refuse the assigned surgery will continue to be monitored in a concomitant control group. The main objective (primary endpoint) of the study is complete biochemical response to therapy after up to 24 months—that is, whether the PSA level falls below 0.2 ng/ml after surgery. In addition, the study will assess whether the unilateral surgery results in fewer side effects. Quality of life and psychological distress will also be documented using questionnaires. Eligible participants are patients aged 18 to 75 with hormone-sensitive, recurrent prostate cancer following radical prostatectomy. No more than three PSMA-PET-positive lymph nodes may be detected on one side of the pelvis, and the PSA level must be below 4 ng/ml. Patients who are not eligible for surgery, those whose PSMA-PET scan shows metastases outside the pelvis or in the former prostate bed, or those who have recently received anti-hormone therapy are not eligible to participate.