JAIN A1, WINDSOR A2, CHOU A3, ROGER S1
1Department of Renal Medicine, Gosford Hospital, Gosford,, Australia, 2Department of Radiation Oncology, Gosford Hospital, Gosford,, Australia, 3Department of Anatomical Pathology, Royal North Shore Hospital, St Leonards, Sydney, Australia
Background: There is limited evidence to guide pelvic radiation therapy (RT) in kidney transplant recipients, where the risk of treatment toxicity is substantial. Acute anatomical and pathological changes within a transplanted kidney during concurrent chemo-radiotherapy (CRT) have not been previously described in the literature.
A 61 year-old female was diagnosed with T2N0M0 anal squamous cell carcinoma six months following kidney transplantation (based on the American Joint Committee Criteria). CRT with curative intent was planned, with standard mitomycin and 5-fluorouracil administration. The proximity of the transplant to the planned RT clinical target volume posed a difficult challenge. Volumetric modulated arc therapy was planned with 54 Gray (Gy) in 30 fractions to the high-risk region, achieving a mean dose of 3.922 Gy to the transplant. Measures including an avoidance structure and cautious margins, accounting for internal movement and anatomical changes, were utilised to minimise toxicity. At fraction 21, an increase in transplant kidney size (427.89 cm³ compared to 260.59 cm³) and medial displacement was noted on cone-beam computed tomography. RT continued following repeat planning, with multidisciplinary consensus as kidney function remained stable. At fraction 27, the patient’s creatinine rose from a baseline of 65 µmol/L to 165 µmol/L with evidence of radiologic and biopsy-confirmed acute cortical necrosis. Treatment was ceased at this point, with a significant improvement to her creatinine level (75±8 µmol/L) noted approximately five months post RT completion.
Conclusions: The significance and long-term clinical consequences of acute anatomical and pathological changes observed during CRT are unclear. Animal models suggest biologic plausibility, but may not apply to conventional fractional RT. Further research will help shape management guidelines adapted to modern RT techniques.
Arunima Jain is currently a second year Nephrology Advanced Trainee at the East Coast Renal Network in New South Wales, with a particular interest in obstetric medicine.