Men with a history of testicular cancer are more likely than other men to later develop high-grade prostate cancer, according to data reported at the Genitourinary Cancers Symposium (Abstract 177).
The meeting is co-sponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology.
“Men with a history of testicular cancer should talk with their doctor about assessing their risk for prostate cancer, given there may be an increased risk,” said Mohummad Minhaj Siddiqui, MD, Director of Urologic Robotic Surgery at the University of Maryland Marlene and Stewart Greenebaum Cancer Center. “A history of testicular cancer was associated with an increased risk of both all prostate cancer and intermediate to high-grade prostate cancer.”
In a news conference webcast for reporters before the meeting, he noted that he and his coauthor, Andrew John Riggin, MD, performed a case control study that involved 32,435 men who had a history of testicular cancer. These men were analyzed along with 147,044 men who had a history of melanoma to determine if there was something different about melanoma as compared with testicular cancer in its relation to later development of prostate cancer.
The group of men diagnosed with melanoma was used as the control group because there was no known relationship between melanoma and prostate cancer, he explained. It was expected that patients with melanoma would have a risk for developing prostate cancer that was similar to that of men in the general population: On average, men in both groups developed prostate cancer about 30 years after their first cancer was diagnosed.
“The cumulative incidence of all prostate cancer by age 80 was 2.8 percent among the men with a history of melanoma, but the incidence of prostate cancer among men with a history of testicular cancer was 12.8 percent, a difference that was statistically significant,” Siddiqui said.
Moreover, when the researchers considered only cases in which the men developed high-risk prostate cancer—defined for the study as intermediate with a Gleason score of 7 or high risk with a Gleason score of 8 or more—the relationship held. “The incidence of intermediate- to high-risk prostate cancer by age 80 was 1.1 percent among the controls and 5.8 percent in patients with a history of testicular cancer,” he continued.
“We looked at risk factors such as age, race, and radiation history and found that even when controlling for the influence of these risk factors, there was still an increased risk of developing intermediate- to high-risk prostate cancer in men with a history of testicular cancer as opposed to the control population.”
‘Groundwork for Future Research for Possible Biologic Link’
Siddiqui said it is too soon to make any practice recommendations based on this single study, but the findings do provide groundwork for further research into the biologic link between the two diseases. “Further validation studies are needed to confirm these results and determine if men with a history of testicular cancer should have closer screening for prostate cancer.”
To perform the study, the researchers analyzed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database of cancer patients from across the United States to identify men with all subtypes of testicular cancer. Siddiqui noted that the search was limited to men over age 40 to allow a sufficient time point for the appearance of prostate cancer.
He and Riggin undertook the project since previous studies had demonstrated an increased rate of prostate cancer in men with a history of testicular cancer, indicating a two to three times higher rate of prostate cancer compared with that in the general public. “However, what has not been studied yet is an important subset of men with intermediate to high-risk prostate cancer and whether there is a relationship of testicular cancer with this type of disease,” Siddiqui said.
Risk, Though, is Still Low
“Prostate cancer was diagnosed in 3,205 men in total,” he continued. “It is important to keep in mind that the chance of developing intermediate- or high-risk prostate cancer is low—95 percent of men with a history of testicular cancer will not get it.”
The news conference's moderator, Charles Ryan, MD, Associate Professor of Medicine and Urology at the University of California, San Francisco, and ASCO's designated expert and a member of the news planning team, commented: “I think it is important to point out that this relates not to the diagnosis of all prostate cancer but to the high-risk patients and that the data do reflect that it had been adjusted to consider prior radiation therapy.”