Hi After hearing your history as she has cervical cancer i think the soft tissue mass near her aorta could be a lesion. I would advise you to do a PET scan. If any lesion is found then biopsy has to be done from the soft tissue mass to prove it is cancerous or not. Sometimes cervical cancer can spread to other parts of body called metastasis and that is why biopsy is necessary. If radiation is needed it can be gone ahead with it and it will not cause any damage to the aorta. Regards Dr Monish De Oncologist.