Where prostate cancer spreads in the body affects survival time
In the largest analysis of its kind, researchers at the Duke Cancer Institute and other top cancer centers have found that the organ site where prostate cancer spreads has a direct impact on survival.
Patients with lymph-only metastasis have the longest overall survival, while those with liver involvement fare worst. Lung and bone metastasis fall in the middle.
"Smaller studies had given doctors and patients indications that the site of metastasis in prostate cancer affects survival, but prevalence rates in organ sites were small, so it was difficult to provide good guidance," said Susan Halabi, Ph.D., professor of biostatistics at Duke and lead author of the study published online March 7 in the Journal of Clinical Oncology.
"With the large numbers we analyzed in our study, we were able to compare all of these different sites and provide information that could be helpful in conveying prognosis to patients," Halabi said. "This information could also be used to help guide treatment approaches using either hormonal therapy or chemotherapy."
Halabi and colleagues from leading U.S. and international cancer research centers pulled data from nine large, phase III clinical trials to analyze outcomes of 8,736 men with metastatic prostate cancer. The patients had all undergone standard treatment with the chemotherapy drug docetaxel.
Site of metastases was categorized into four groups: lung, liver (without lung), lymph nodes only, bone with or without lymph nodes and no other organ metastases.
Most patients, nearly 73 percent, had bone metastases, and their overall median survival was just over 21 months. Men with lymph involvement only were the smallest subset—6.4 percent—but had the longest median survival at about 32 months.
Men with liver metastasis represented 8.6 percent of the patients, and had the worst median survival of nearly 14 months. Men with lung metastases had a median 19 survival time of 19 months, and represented 9.1 percent of the study population.
"These results should help guide clinical decision-making for men with advanced prostate cancer," Halabi said. "They also suggest that prognostic subgroups should be considered for investigational therapies that are tested in clinical trials."
Halabi said more research is needed to understand how and why prostate cancer spreads to different organs.