De novo cancer in patients on dialysis and after renal transplantation: north-western Italy, 1997-2012

BACKGROUND

Kidney transplant recipients (KTR) are known to have a higher risk of cancer than the general population, especially of malignancies related to oncogenic viral infections. This study assessed the incidence of de novo malignancies (DNMs) in patients receiving kidney transplantation and in dialysis patients (DP) on the waiting list for transplantation at the same centre. The aim was to quantify the contribution of post-transplant immunosuppression to the underlying risk of developing a DNM in dialysis patients on the waiting list for kidney transplant.

METHODS

Cancer incidence rates were computed using the Kaplan-Meier product-limit method. The number of DNMs observed in both groups was compared to the expected incidence in the general Italian population through calculation of the standardized incidence ratios (SIR) and their 95% confidence intervals (CI). To identify risk factors, incidence rate ratios (IRR) and 95% CIs were computed using Poisson regression analysis. The comparison of incidence rates between the two cohorts was also performed using age standardized incidence rates (ASR) and their ratio (age standardized rate ratio, ASRR).

RESULTS

In 4858 person-years (PYs) of observation, 75 out of 735 KTR were diagnosed with DNM: 57 solid neoplasms, 13 post-transplant lymphoproliferative disorders (PTLD), and 12 Kaposi sarcomas (KS). The overall incidence was 17.5 cases/10³ PYs, resulting in a 2.1-fold increased risk. Twenty-four out of 912 DP, over a follow-up of 2400 PYs, were diagnosed with a solid neoplasm, but none had PTLD or KS. The use of induction therapy after transplant was associated with a significant increased risk of KS (IRR: 3.52; 95% CI 1.04-11.98, p < 0.05). ASRR for all cancers and for solid cancers only was 1.84- and 1.19-fold higher in KTR, respectively, than in the general population. The overall incidence in DP was 10.0 cases/10³ PYs, with a 1.6 significantly increased cancer risk compared to the general population.

CONCLUSION

Our study confirms the increased risk of cancer after transplantation and during dialysis, but showed that virus-related cancers only occur after post-transplant immunosuppression.

Diethylene glycol poisoning from transcutaneous absorption

A case of transcutaneous diethylene glycol poisoning with severe acute kidney injury, but a positive outcome, is described. A man without significant medical history was admitted to our hospital due to anuria, gastrointestinal symptoms, and hypertension. Ultrasonography excluded vascular damage and postrenal obstruction. Laboratory tests showed acute kidney injury and metabolic acidosis with increased anion gap; hemodialysis therapy was started. The brother of the patient reported that the patient had been smearing his skin with brake fluid containing diethylene glycol to treat a "dermatitis." Only supportive therapy was given due to the lack of a specific antidote. Continuous venovenous hemofiltration was performed. The kidney biopsy showed acute toxic proximal tubulonecrosis, without deposition of oxalate crystals. His neurologic condition worsened dramatically; supportive care was continued. Over time, acute kidney injury and neurologic damage gradually improved; 33 days after admission, he went to a rehabilitation unit for 5 months, with complete clinical recovery. Historically, diethylene glycol has been the cause of large-scale poisonings from ingestion of contaminated drugs. The clinical evolution is unpredictable. Treatment is not well defined; early hemodialysis treatment reduces levels of toxic metabolites, and fomepizole could be useful in cases with an early diagnosis. A comparison of the characteristics of diethylene glycol versus ethylene glycol poisoning is given.