DALLAS — June 2, 2008 —
A UT Southwestern Medical Center physician and other researchers have
developed a unique statistical model that predicts the probability of a
patient being cancer free 12 years after initial surgical treatment.
The model, known as a nomogram, uses tumor and patient characteristics
to maximize predictive accuracy. Scientists said that knowing the
likelihood of the cancer’s return can help clinicians counsel patients
and to customize treatment recommendations for individual patients.
The researchers built the predictive model using data from more than
2,500 renal cancer patients in databases at Memorial Sloan-Kettering
Cancer Center and the Mayo Clinic. The model is described in June’s
edition of the
Journal of Urology.
Dr. Ganesh Raj, assistant professor of urology
and lead author, hopes nomograms will help physicians identify and
counsel patients at high risk for renal cancer.
“It is our hope that the nomogram will help physicians identify and counsel patients at high risk for cancer recurrence,” said Dr. Ganesh Raj, assistant professor of urology and lead author of the published study.
“If the cancer appears only in the kidneys, it can often be treated
with a partial or radical nephrectomy,” he said. “This nomogram is
designed for use in the initial counseling session after diagnosis and
enables patients to have a clearer understanding of their cancer
outcomes with surgery.”
Renal cancer is the most common form of kidney cancer. A nephrectomy,
or surgical removal of the kidney, is often the initial treatment.
Kidney cancer is notoriously resistant to radiation therapy and
chemotherapy, although some cases respond to immunotherapy. Recently
developed molecular therapies have also shown great promise for
A history of smoking greatly increases the risk for developing
kidney cancer. Blood in the urine, flank pain and a mass in the abdomen
are classic signs of renal cancer. Unfortunately, by the time a patient
displays these symptoms, the disease is often advanced beyond a
In 2007, more than 51,000 new cases of renal cancer were diagnosed in
the U.S. A majority of the tumors were discovered incidentally in
patients who had no symptoms. Because imaging techniques such as
computerized tomography (CT) are now being used more often for a
variety of conditions, early diagnosis of renal cancer is more common.
“Historically renal cancer was associated with a tremendously poor
diagnosis,” Dr. Raj said. “However, more and more cases are being
diagnosed incidentally and earlier thanks to the increased usage of
imaging techniques. A patient will have a CT scan to evaluate unrelated
symptoms and be told he or she has a mass in the kidney.”
The nomogram relies on patient characteristics to make a statistical
prediction. Gender, the presence or absence of symptoms, and the mass’s
size are among the input data. For example, a woman with an
incidentally discovered, 3-centimeter renal mass has a 96 percent
chance of being cancer free 12 years after surgery alone, Dr. Raj said.
In comparison, a man with a 4-centimeter renal mass found as a result
of seeing his physician after having flank pain, and with imaging tests
showing the lymph nodes are enlarged, has less than a 40 percent chance
of being cancer free 12 years after surgery.
“This model allows us to better predict a patient’s chances of
reoccurrence even before surgery,” Dr. Raj said. “The nomogram is a
prognostic tool physicians can use to better counsel patients on how
curable their cancer may be with just surgery, or if alternative
treatments will likely be needed. In the examples of the two patients
with similar sized renal masses, I might consider using a more
aggressive treatment course and follow-up schedule for the man than the
woman based on their nomogram results.”
Researchers from the Mayo Clinic in Rochester, Minn., the Mayo Medical
School and the Cleveland Clinic also participated in the study.