Literatus: The cancer-inducing therapy

LAST month, we presented here the general picture of kidney transplantation based on the multicenter study conducted by Behzad Einollahi and colleagues as reported in the Journal of Cancer (June 2012).

This week you will know, in more detail, which immunosuppressant drugs have been causing it and briefly how. The study noted that the risk of developing malignancy in organ transplants is three-four times greater than general population.

Before 2000, patients received a two-drug maintenance regimen consisting of prednisone and cyclosporine or azathioprine (AZA); or, a triple therapy with cyclosporine, prednisone and AZA. Afterward, most patients received not just cyclosporine and prednisone but mycophenolate mofetil (MMF) as well. Today, immunosuppressive therapy is a three-drug therapy using cyclosporine/sirolimus, MMF/AZA and steroids.

The Einollahi study noted that more than half of the patients (61.3 percent) received AZA when they developed cancer. The remaining received MMF. The AZA regimen developed mostly post-transplantation lymphoproliferative disorder (PTLD); while MMF protocol had mostly resulted to Kaposi’s sarcoma (KS) tumors.

It appeared that AZA directly worsens the damaging effects of UV radiation on the skin and augment reduction of local and systemic immune responses during sun exposure. It sensitizes DNA to UVA radiation, disabling it from neutralizing radioactive radicals penetrating the body.

In adults worldwide, PTLD is the second most common cancer in post-transplantation, representing up to 12 percent of patients. In children, it is the most common at as much as 50 percent, making it almost four-fold higher than adults. Recipients have a poor diagnosis, too. It’s the common cause of death in both genders and in all age groups. Its survival rate was 74.6 percent after 14 years post-diagnosis.

Conversely KS tumors showed second highest survival rate in year one post-diagnosis, following non-KS tumors (100 percent). Between the second and fifth year, non-KS continued at 98.2 percent survival rate, and have the longest survival time of 164.8 months. KS only have 132.26 months.

Solid tumors were the worst of all. Although less common, they have the lowest survival rate. Its survival time was shortest (25.49 months). Recurrence too increased.

Susan Casey, the former creative director of Outside magazine who stayed for weeks in the Farallones National Marine Sanctuary watching great white sharks, wrote in her book The Devil’s Teeth (2005): “Survival usually trumps curiosity and that’s good.”

Our curiosity in knowing about kidney transplantation may turn out useful in our battle to stick around and continue the race.