Philip W. Kantoff, MD

Recent progress in our understanding of the pathogenesis of advanced prostate cancer has heralded a new era in treatment. Numerous agents now populate the treatment landscape, and an impressive number of novel agents are in development. However, many questions remain unanswered, paving the path for discovery in the future.

Hormone-refractory prostate cancer (HRCaP) is both heterogeneous and lethal. Multiple treatment options exist, including secondary hormonal manipulations, chemotherapy, experimental options, and best supportive care. Choosing the appropriate therapy for an individual patient depends on several important clinical factors such as the presence or absence of symptomatic metastatic disease, age and comorbidities, and prostate-specific antigen velocity. While only docetaxel (Taxotere)-based chemotherapy has been proven to improve survival in this setting, a wide range of therapies may be effective for any individual. Palliative maneuvers, such as external-beam radiation, bisphosphonate therapy, radiopharmaceuticals, and pain management are critical for appropriate patient management. Several promising novel therapies are in late-stage testing and will hopefully provide more treatment options for these patients.

In this review, we describe how clinical investigators addressed some of the challenges in prostate cancer chemotherapy trials 20 years ago, and we indicate what has evolved in the field since that time. We consider the impact that prostate-specific antigen measurement had in this setting, evolving clinical paradigms, multidisciplinary programs, and the current armamentarium of cancer treatment, including targeted molecular therapy, for patients with hormone-refractory disease.

Androgen-deprivation therapy, usually with combined androgenblockade, is standard initial treatment for advanced prostate cancer.With failure of initial treatment, as indicated by rising prostate-specificantigen (PSA) levels, second-line hormonal therapy is usually instituted.Over the past several years, it has become increasingly clear thatsystemic chemotherapy has an important role in hormone-refractorydisease. Phase II trials have demonstrated high PSA and measurabledisease response rates with taxane single-agent and combination treatments.One recent phase III trial showed that docetaxel (Taxotere)/estramustine (Emcyt) significantly improved overall survival, progression-free survival, and PSA response rate compared with mitoxantrone(Novantrone) plus prednisone. Another phase III trial demonstratedthat docetaxel given every 3 weeks plus prednisone significantly improvedoverall survival, PSA response rate, pain relief response rate,and quality of life compared with mitoxantrone and prednisone. Onthe basis of these findings, every-3-week docetaxel plus prednisone isnow considered standard first-line therapy for metastatic hormonerefractorydisease. There is considerable optimism that treatment canbe further improved. Studies of taxane combinations with bevacizumab(Avastin), thalidomide (Thalomid), bortezomib (Velcade), antisenseBcl-2 oligonucleotide, mTOR inhibitors, epidermal growth factor receptorinhibitors, and KDR inhibitors are under way. Randomized phaseIII trials in progress or planned are examining docetaxel in combinationwith imatinib mesylate (Gleevec) or calcitriol and docetaxel/prednisonein combination with bevacizumab and an antisense clusterincompound. Other promising systemic agents include epothilones andatrasentan, and promising vaccines include Provenge, GVAX, andProstvac.