Medical adrenalectomy for advanced prostatic cancer: clinical and hormonal effects

Increased expression of genes converting adrenal androgens to testosterone in androgen-independent prostate cancer

Androgen receptor (AR) plays a central role in prostate cancer, and most patients respond to androgen deprivation therapies, but they invariably relapse with a more aggressive prostate cancer that has been termed hormone refractory or androgen independent. To identify proteins that mediate this tumor progression, gene expression in 33 androgen-independent prostate cancer bone marrow metastases versus 22 laser capture-microdissected primary prostate cancers was compared using Affymetrix oligonucleotide microarrays. Multiple genes associated with aggressive behavior were increased in the androgen-independent metastatic tumors (MMP9, CKS2, LRRC15, WNT5A, EZH2, E2F3, SDC1, SKP2, and BIRC5), whereas a candidate tumor suppressor gene (KLF6) was decreased. Consistent with castrate androgen levels, androgen-regulated genes were reduced 2- to 3-fold in the androgen-independent tumors. Nonetheless, they were still major transcripts in these tumors, indicating that there was partial reactivation of AR transcriptional activity. This was associated with increased expression of AR (5.8-fold) and multiple genes mediating androgen metabolism (HSD3B2, AKR1C3, SRD5A1, AKR1C2, AKR1C1, and UGT2B15). The increase in aldo-keto reductase family 1, member C3 (AKR1C3), the prostatic enzyme that reduces adrenal androstenedione to testosterone, was confirmed by real-time reverse transcription-PCR and immunohistochemistry. These results indicate that enhanced intracellular conversion of adrenal androgens to testosterone and dihydrotestosterone is a mechanism by which prostate cancer cells adapt to androgen deprivation and suggest new therapeutic targets.

Effect of combination therapy with aminoglutethimide and hydrocortisone on prostate-specific antigen response in metastatic prostate cancer refractory to standard endocrine therapy

A prospective study was performed to investigate the combination of the aromatase inhibitor aminoglutethimide and hydrocortisone in androgen-independent prostate cancer with changes in prostate-specific antigen (PSA) level as main determinant for response. Thirty-five patients were treated with aminoglutethimide 1000 mg daily and hydrocortisone acetate 40 mg daily. PSA measurements were performed every month. If evaluable lesions were present, objective tumor assessment was done by computed tomography scan and X-ray investigations. In 12 patients (37%) the PSA value showed a confirmed response with a decline in serum level of at least 50%. Median time to progression in responding and all patients was 10.5 and 4.5 months, respectively. Median duration of response in responding patients was 9 months. Median survival for these two groups was 23 and 14.5 months, respectively. Of seven patients with measurable disease, two showed a partial response and five a stable disease. Improvement in general condition, pain and feeling of well-being was noted in two-thirds of patients. Therapy was well tolerated with mainly grade I and II adverse events in 20% of patients. We conclude that aminoglutethimide is a valuable second-line therapy for patients with androgen-independent prostate cancer.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.

Flutamide versus prednisone in patients with prostate cancer symptomatically progressing after androgen-ablative therapy: a phase III study of the European organization for research and treatment of cancer genitourinary group

PURPOSE

Time to progression (TTP), overall survival, and quality of life (QL) were compared in patients with hormone-resistant prostate cancer (HRPC) treated with prednisone (5 mg orally, four times a day) or flutamide (250 mg orally, three times a day).

PATIENTS AND METHODS

Symptomatic patients were randomized to receive either prednisone (101 patients) or flutamide (100 patients). Subjective response was assessed based on performance status, the use of analgesics, and the need to apply alternative palliative treatment. Prostate-specific antigen (PSA)-based biochemical response (>or= 50% reduction of baseline PSA) was recorded. At baseline and at 6-week intervals during follow-up, patients completed the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C-30.

RESULTS

There was no difference between the groups in median TTP (prednisone, 3.4 months; flutamide, 2.3 months) or overall survival (prednisone, 10.6 months; flutamide, 11.2 months). In the prednisone group, 56% of the patients experienced a subjective response, compared with 45% in the flutamide group (P: = .18). The median response duration was 4.8 months for prednisone and 4.2 months for flutamide. A biochemical response was observed in 21% and 23% of the prednisone and flutamide groups, respectively. Gastrointestinal toxicity was the reason for trial discontinuation in seven patients receiving flutamide and two patients receiving prednisone. The QL assessment parameters favored the use of prednisone with statistically significant differences in pain, fatigue, role functioning, appetite loss, gastrointestinal distress, and overall QL.

CONCLUSION

In symptomatic HRPC, treatment with prednisone or flutamide leads to similar rates of TTP and overall survival and no difference in subjective or biochemical response. The QL results favor the use of low-cost prednisone in patients with HRPC.

Hormone-refractory (D3) prostate cancer: refining the concept

OBJECTIVES

A wide range of responses have been reported to second-line hormonal therapies, including corticosteroids and the withdrawal of antiandrogens in patients with hormone-refractory prostate cancers. This suggested the need to classify patients on the basis of hormonal sensitivity. A schema was developed by assessing the differences in entry criteria in relation to outcomes for clinical protocols with hydrocortisone alone or in combination with other agents for patients who had progressed after primary hormone therapy.

METHODS

Published clinical trials of patients who had progressed after primary hormone treatment, which included glucocorticoids, were retrieved from Medline listings. The trials included patients treated with hydrocortisone alone, hydrocortisone and aminoglutethimide, hydrocortisone plus suramin, dexamethasone, and prednisone alone or in combination with chemotherapy.

RESULTS

The definitions used for refractory disease ranged from none, to "progression", to "unsuccessful second medical or surgical castration. "None of the trials included a definition for hormone-refractory disease based on objective criteria. Details were lacking on most trials with respect to the response to and specific types of hormonal therapies. Furthermore, few trials controlled for the potential contribution of the "flutamide withdrawal syndrome" on outcome.

CONCLUSIONS

The term "hormone-refractory" prostate cancer has evolved to include patients with a spectrum of diseases. As utilized in clinical trials of second-line hormonal therapies, patients who have received one and as many as six different treatments have been included in the same study. A new classification of patients based on hormonal sensitivity is proposed to recognize that androgen-independent proliferation, progression of disease despite castrate levels of testosterone, does not necessarily mean that a tumor is refractory to hormonal manipulations. Future trials in hormonally relapsed patients must include more details of the hormonal therapies utilized.