Hormones secreted by malignant tumors could be responsible.

Surgery for kidney cancer may help resolve concomitant arterial hypertension, according to a study.

The study focused on 40 patients from Northeast Montenegro with renal tumors, 29 of whom had renal cell carcinoma (RCC). The other 11 had benign tumors and served as controls. Of the 29 RCC patients, 24 underwent radical nephrectomy and one had a partial nephrectomy.

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Four patients had inoperable advanced cancer. The patients had an average age of 56 years (range 3-76 years). Twenty-three RCC patients had long-standing high systolic and diastolic pressure compared with only two of the patients with benign tumors.

Systolic and diastolic pressure declined significantly in the 25 RCC patients who underwent nephrectomy, investigators reported in Clinical and Experimental Nephrology (2009; published online ahead of print). Mean systolic pressure dropped from 161 to 137 mm Hg and mean diastolic pressure fell from 99 to 77 mm Hg. The benign-tumor group did not experience a significant drop in BP after surgery.

The investigators, led by Milan Stojanovic, MD, PhD, a radiologist at the Regional Medical Center and Hospital in Berane, Montenegro, hypothesized that the RCC patients’ hypertension was caused by their cancer, likely via elevated levels of endothelin-1 and urotensin-II.

These hormones are potent vasoconstrictors believed to be excreted by tumors. After surgery, the researchers speculated, the influence of another vasoconstrictor, adrenomedullin, takes over. The three RCC patients whose BP did not resolve after surgery likely had another cause of their hypertension, the authors noted.

One of the investigators, Branislav Goldner, MD, PhD, a radiologist in the Diagnostic Imaging Center of the Bezanijska Kosa Hospital and the University of Belgrade School of Medicine, said that the logical next step in the research is to verify the vasoconstrictive action of endothelin-1 and urotensin-II from a large number of samples of malignant renal tissue in vitro.

James M. McKiernan, MD, who has conducted extensive research into renal tumors, said the Serbian investigators make a convincing argument.

“This is a fascinating issue, one of the chicken vs. the egg,” said Dr. McKiernan, director of urologic oncology at Columbia University Medical Center in New York City. “That is, does hypertension cause renal cell carcinoma or does renal cell carcinoma cause hypertension, and if so, can nephrectomy cure the hypertension? We have anecdotally observed similar resolution of hypertension after partial and radical nephrectomy here at Columbia. I think their proposed mechanism makes sense, and I also think that reducing or controlling hypertension could reduce the incidence of renal cell carcinoma.”