Value of endocrine therapy for early and locally advanced prostate cancer

The role of luteinizing hormone-releasing hormone therapy in locally advanced prostate cancer and biochemical failure: considerations for optimal use

BACKGROUND

More patients are being diagnosed with prostate cancer at an earlier age with earlier stage disease because of advances in screening and detection. Investigators continue to explore the use of hormone therapy, particularly luteinizing hormone-releasing hormone (LHRH) analogues, earlier in the course of disease.

OBJECTIVE

This review summarizes clinical evidence regarding the safety and efficacy of LHRH analogues in the treatment of locoregional disease or following biochemical failure.

METHODS

Relevant information from clinical studies was identified through a MEDLINE search of the medical literature published in English in the last 5 years (search terms: LHRH and prostate cancer). The search included prospective and retrospective clinical studies on LHRH therapy in locally advanced prostate cancer. Additional relevant publications published before 1999 were identified from citations in the resulting articles.

RESULTS

The available clinical evidence suggests that the use of LHRH analogues as adjuvant or neoadjuvant therapy in conjunction with radiation therapy may improve survival outcomes. Few studies have evaluated the use of LHRH analogues after biochemical failure. However, several related studies indicate that initiating hormone therapy earlier rather than later may provide some clinical benefit. When considering early initiation of LHRH therapy, the potential risks of long-term treatment must be considered. Physiologic changes, such as deterioration of body composition and bone quality, may have important effects on the risk of developing cardiovascular disease and osteoporosis.

CONCLUSIONS

Although some clinical evidence supports the use of LHRH analogues as adjuvant or neoadjuvant therapy or following biochemical failure, further study is needed. In the meantime, clinicians should carefully weigh the potential benefits and risks of early hormone therapy when making treatment decisions.

Endocrine treatment of prostate cancer

Although androgen deprivation as a treatment for patients with prostate cancer was described more than 60 years ago its optimal use remains controversial. The widespread use of prostate-specific (PSA) assay has lead to earlier diagnosis and earlier detection of recurrent disease. This means that the systemic side effects of androgen deprivation and quality of life have become more important. Debates continue regarding the proper use and timing of endocrine therapy with orchiectomy, oestrogen agonists, gonadotropin hormone-releasing hormone (GnRH) agonists, GnRH antagonists, and androgen antagonists. A critical review of the literature was performed. Data support that androgen deprivation is an effective treatment for patients with advanced prostate cancer. However, although it improves survival, it is not curative, and creates a spectrum of unwanted effects that influence quality of life. Castration remains the frontline treatment for metastatic prostate cancer, where orchiectomy, oestrogen agonists and GnRH agonists produce equivalent clinical responses. Maximum androgen blockade (MAB) is not significantly more effective than single agent GnRH agonist or orchiectomy. Nonsteroidal antiandrogen monotherapy is as effective as castration in treatment of locally advanced prostate cancer offering quality of life benefits. Adjuvant endocrine treatment is able to delay disease progression at any stage. There is, however, controversy of the possible survival benefit of such treatment, including patients having PSA relapse after definitive local treatment for prostate cancer. Neoadjuvant endocrine treatment has its place mainly in the external beam radiotherapy setting. Intermittent androgen blockade is still considered experimental. The decision regarding the type of androgen deprivation should be made individually after informing the patient of all available treatment options, including watchful waiting, and on the basis of potential benefits and adverse effects. Several large studies are under way to investigate the role of adjuvant endocrine treatment in the field of early prostate cancer, intermittent androgen deprivation and endocrine therapy alone compared with endocrine therapy with radiotherapy. The real challenge, however, is to develop better means to avert hormone-refractory prostate cancer and better treatments for patients with hormone-refractory disease when it occurs.