Men whose castration-resistant prostate cancer (mCRPC) has metastasized to the liver have the worst overall median survival when compared with those with lymph-only, lung, or bone metastases, the largest meta-analysis of its kind has found.1
These results can change the current treatment landscape for men in each of the metastatic subgroups.
“Physicians may treat men with liver metastases more aggressively (such as with chemotherapy) than men if they had bone or liver metastases,” lead study author Susan Halabi, PhD, professor of biostatistics at Duke University in Durham, NC, told Cancer Therapy Advisor.
The impetus behind the study was to determine if liver metastases had an impact on survival, which had been suggested in past studies with small numbers of men with liver or lung metastases.
“Our understanding of what drives the development of different metastatic patterns of this disease is limited and underscores the need to biopsy patients with recurrences to identify underlying mechanisms and develop novel treatment approaches for men with mCRPC,” Dr Halabi reported.
Investigators from 20 United States and international cancer research centers pulled individual patient data on 8820 men enrolled in 9 phase 3 study trials between October 1999 and November 2012: SWOG 9916, TAX 327, Cancer and Leukemia Group B (CALGB) 90401, SWOG 0421, VENICE, Endothelin A Use (ENTHUSE), READY, MAINSAIL, and SYNERGY.
In all trials, patients received docetaxel vs docetaxel plus an experimental agent. Although a tenth trial was identified, Androgen-Independent Prostate Cancer Study of Calcitriol Enhancing Taxotere (ASCENT), the sponsor “became financially insolvent and was unable to provide the trial data,” the authors wrote.
Metastatic disease was classified as 1 of 2 mutually exclusive groups, non-visceral or visceral disease.
“Visceral disease was broadly defined as soft tissue metastases other than lymph node metastases, and included metastatic disease to lung, liver, adrenal glands, brain, and others (unspecified),” the authors wrote. Patients with visceral disease were categorized as (1) having liver metastases even if they had other metastatic sites; (2) having lung metastasizes unless they also had liver metastases; and (3) having non-hepatic, non-pulmonary visceral metastases (eg, adrenal, kidney, and others).
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“In the non-visceral disease group, patients were classified as either having lymph node only disease, or bone metastases with or without nodal involvement,” they noted.
Primary endpoint was overall survival, defined as the interval between date of randomization and date of death from any cause.