Thanks for posting your query.
Renal cell carcinoma
spread by inferior vena cava
and inferior vena cava drains blood from lower limbs and blood goes fromright sided heart to lungs.
So there may be two possibilites : Metastasis and pneumonia
With spread of cancer, there is decreased immunity and chemotherapy
also decrease the immunity, so there is risk of pneumonia.
Spread may also cause metastasis in lungs.
As she is on ventilator and it indicates is not a good condition.
Prognosis of renal cell carcinoma after spread is also not good.
God blees her,
Dr. Mayank Bhargava