Stage II seminoma is a type of cancer that is usually highly curable and most often affects young men.

Radiotherapy is an effective treatment, but it can sometimes cause side effects in the long term and, rarely, increase the risk of developing another cancer later in life.For this reason, more targeted treatments are being explored, such as proton therapy (PBT). This type of radiotherapy uses protons to better focus the treatment on the tumor while reducing exposure to the surrounding healthy tissues.The goal is to treat the cancer effectively while minimizing side effects as much as possible.

Inclusion Criteria:

• Age ≥ 18 years
• Male gender
• ECOG Performance status 0 - 1
• Histologically confirmed diagnosis of testicular seminoma
• Stage IIA - IIB disease with metastatic involvement limited to retroperitoneal lymph nodes measuring ≤3 cm in greatest diameter
• Prior radical orchiectomy
• Clinical indication for radiotherapy
• Written informed consent provided

Exclusion Criteria:

• Non-seminomatous germ cell tumor histology
• Incomplete definitive surgical orchiectomy, including diagnostic biopsy alone
• Prior or concurrent second malignancy other than non-melanoma skin cancer, unless disease free for a minimum of five years
• Prior radiotherapy to the abdominal or pelvic region
• Known severe, active co-morbidity
• Inability or refusal to provide informed consent