He had a ct scan in November colonoscopy.  Results stating or investigation from the hospital states

Mildly enlarged retroperitoneal lymphoma nodes 1.1 cm retro canal node previously in June 2021 mri image was 0.4 cm.

Letter states they are suspicious of metastatic nodal disease as my dad had prostate cancer on June 2021.  Last PSA in April 2025 was 0.01.

can any explain or give me any information and could it be something else?