Prognostic factors in patients with prostate cancer refractory to endocrine therapy: univariate and multivariate analyses including doubling times of prostate-specific antigen and prostatic acid phosphatase

Prognostic value of serum alkaline phosphatase in the survival of prostate cancer: evidence from a meta-analysis

BACKGROUND

Many studies have evaluated the relationship between alkaline phosphatase (ALP) and the prognosis for prostate cancer (PCa). But they have not reached a widespread consensus yet. Therefore, we completed a meta-analysis to ascertain the significance of ALP and the prognosis for PCa.

METHODS

A literature search was performed in the PubMed, Embase, and Web of Science databases. HRs concerning overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS) were extracted to evaluate the impacts of ALP on the prognosis for PCa. Subgroup analyses were conducted on different study types, regions, sample sizes, and cutoff values. Sensitivity analysis was performed by removing one study in sequence.

RESULTS

A total of 63 studies from 54 articles with 16,135 patients were included in this meta-analysis. The pooled results indicated that high baseline ALP was associated with obviously poor OS (HR=1.74, 95% CI: 1.47-2.06) and PFS (HR=1.60, 95% CI: 1.13-2.26) in patients with PCa. The pooled HR for bone-specific ALP and OS was 1.76 (95% CI: 1.45-2.15). However, no association between ALP and CSS (HR=1.002, 95% CI: 0.998-1.005) was found for PCa. The results of subgroup analyses were all in accordance with the main findings. Sensitivity analysis suggested that no single study could affect the stability of the results.

CONCLUSION

High serum ALP is significantly associated with poor OS and PFS except for CSS in PCa. ALP is an efficient and convenient biomarker for PCa prognosis.

[Prognostic factors for estrogen therapy of relapsed prostate cancer after maximal androgen blockade (MAB)]

PURPOSE

Advanced prostate cancer responds well to endocrine therapy initially, but soon becomes refractory and has a poor prognosis. We analyzed the prognostic factors of prostate cancer responding well initially to maximal androgen blockade (MAB) but later showing PSA relapse and treated with estrogen.

MATERIALS AND METHODS

In prostate cancer patients newly diagnosed from January 1992 to December 2008 at our institution, there were 85 patients in that the PSA level dropped below 10 ng/ml by MAB, but showed PSA relapse thereafter and treated with estrogen. We investigated the relationship between age at diagnosis, clinical stage, pathological differentiation, initial PSA, the value of PSA nadir, duration between diagnosis and initiation of estrogen therapy, duration between PSA failure and initiation of estrogen therapy, the value of PSA at estrogen therapy, PSA doubling time (PSA-DT) at estrogen therapy, PSA response three months after initiation of estrogen therapy, use of diethylstilbestrol diphosphate (DES-P) at the initial stage of therapy, local radiotherapy to prostate, type of estrogen and prognosis after estrogen therapy.

RESULTS

In Kaplan-Meier method, factors which showed poorer prognosis were stage B and D, poorly differentiated, PSA 11.9 ng/ml or higher at estrogen therapy, PSA-DT shorter than 2.3 months before estrogen therapy and PSA response without CR three months after initiation of estrogen therapy. In multivariate analysis, the factor that most significantly affected prognosis after estrogen therapy was PSA response three months after initiation of estrogen therapy (hazard ratio: 12.61), followed by PSA-DT at estrogen therapy (hazard ratio: 2.59).

CONCLUSION

We investigated the prognostic factors refractory to MAB and treated with estrogen. These results are useful in planning the therapy, and in explaining the status or future prospective of the disease to families and patients.

First- and second-line chemotherapy with docetaxel or mitoxantrone in patients with hormone-refractory prostate cancer

BACKGROUND

Docetaxel and mitoxantrone are considered first-line chemotherapeutic options in patients with hormone-refractory prostate cancer (HRPC), but their clinical effectiveness in a second-line setting is unknown. Therefore, the authors conducted a population-based retrospective study to establish activity and tolerability of second-line docetaxel or mitoxantrone in HRPC.

METHODS

The study included 68 patients who had failed androgen ablation therapy and who received docetaxel and mitoxantrone in either sequence. Clinical efficacy in terms of median overall survival (OS), progression-free survival (PFS), posttreatment prostate-specific antigen (PSA) decline of > or = 50% and treatment-related toxicity were evaluated.

RESULTS

Of 68 patients, 35 received docetaxel followed by mitoxantrone, and 33 received mitoxantrone followed by docetaxel. Both groups were comparable for recognized pretreatment prognostic factors. Patients who received docetaxel first-line had a trend toward longer median OS compared with patients treated with second-line docetaxel after mitoxantrone failure (22 mos, 95% confidence interval [CI], 17.2-26.8 mos vs. 15 mos, 95% CI, 10.4-19.6 mos). Median number of second-line chemotherapy cycles was 3 and median PFS survival was 2-3 months in both groups. Second-line docetaxel produced a higher PSA response compared with mitoxantrone (38% vs. 12%, P = 0.012), but this did not translate to a survival benefit. Both second-line docetaxel and mitoxantrone were associated with a high frequency of treatment-related adverse events that resulted in dose reduction, delay, or discontinuation (64% and 46% of patients, respectively).

CONCLUSIONS

Study results favored docetaxel given up-front for patients with HRPC considered suitable for further chemotherapy. Second-line docetaxel or mitoxantrone had limited efficacy and tolerability. Patients who are candidates for second-line chemotherapy, should be enrolled into clinical trials.

Prognostic model of event-free survival for patients with androgen-independent prostate carcinoma

BACKGROUND

The current study was conducted to develop a prognostic model of event-free survival (EFS) in men with androgen-independent prostate carcinoma (AIPC).

METHODS

Data from 160 patients diagnosed with AIPC between 1989-2002 were reviewed. No patient had received cytotoxic chemotherapy. A univariate Cox proportional hazards model identified significant predictors of EFS. Recursive partitioning analysis divided these significant variables into prognostic risk groups. The final prognostic model was tested with a Cox proportional hazards model.

RESULTS

The final prognostic risk model included the presence of metastatic disease at the time of androgen-independent disease progression (P = 0.040), time to prostate-specific antigen (PSA) recurrence (P = 0.043), and PSA doubling time (P < 0.01). Three highly independent risk groups were identified. The observed median EFSs were 6.1 months (95% confidence interval [95= CI], 3.4-8.8 months), 33.6 months (95= CI, 25.3-41.9 months), and 96.1 months (95= CI, 57.9-134.3 months) for the low-risk, intermediate-risk, and high-risk groups, respectively. Each risk group was found to be independently predictive of EFS (P < 0.01). Patients who died of prostate carcinoma experienced significantly more clinical events than those who died of other causes (P < 0.01).

CONCLUSIONS

The prognostic model in the current study stratified patients into three highly significant and independent risk groups for EFS. A detailed PSA history and knowledge of metastatic disease are sufficient to risk-stratify patients with AIPC. One very unique aspect of this model was that it was developed from a patient cohort that never received chemotherapy.

THE NATURAL HISTORY OF ANDROGEN INDEPENDENT PROSTATE CANCER

PURPOSE

We describe the natural history of androgen independent prostate cancer (AIPC) in the modern prostate specific antigen (PSA) era.

MATERIALS AND METHODS

Data from 160 patients diagnosed with AIPC between 1989 and 2002 were reviewed. No patient had received cytotoxic chemotherapy. Univariate and multivariate proportional hazards models were constructed to identify significant risk factors for cancer specific survival. Recursive partitioning analysis stratified patients into prognostic risk groupings. The types and frequencies of cancer specific complications per risk grouping were compared.

RESULTS

The final prognostic risk model included nadir PSA on androgen deprivation therapy (p = 0.023), time to PSA recurrence (p = 0.006) and prostate specific antigen doubling time (p <0.01). Three highly independent risk groupings were identified. The observed median cancer specific survivals were 14.0 months (95% CI, 8.3-19.8), 38.4 months (95% CI, 26.9-49.9) and 89.1 months (95% CI, 69.0-109.2) for low, intermediate and high risk groupings, respectively (p <0.001). Patients in the low risk grouping experienced significantly fewer cancer specific complications (p = 0.003).

CONCLUSIONS

This prognostic model stratified patients into 3 highly significant and independent risk groupings. A detailed PSA history alone is sufficient to risk stratify patients with AIPC.

Prostate-specific antigen doubling time predicts response to deferred antiandrogen therapy in men with androgen-independent prostate cancer

OBJECTIVES

To identify the pretreatment variables that are predictive of response and the duration of response to deferred antiandrogen therapy in men with androgen-independent prostate cancer (AIPC).

METHODS

A total of 375 patients receiving androgen deprivation therapy for advanced prostate cancer between 1977 and 2002 had medical records available for retrospective review. Of these 375 patients, 163 were diagnosed with AIPC. The inclusion criteria included (1) diagnosis of AIPC and (2) treatment with deferred antiandrogen therapy. AIPC was biochemically defined as two consecutive rises in the prostate-specific antigen (PSA) level during androgen deprivation therapy. The treatment response to deferred antiandrogen therapy was defined as a 50% or greater decline in the pretreatment PSA level. The prognostic value of various pretreatment parameters was determined with the appropriate statistical methods and tested with a Cox proportional hazards model.

RESULTS

Of the 163 patients with AIPC, 36 were treated with deferred antiandrogen therapy. Of these 36 patients, 12 (33.3%) experienced a PSA response. The median PSA failure-free survival was 9.0 months (95% confidence interval 5.2 to 12.9). The only pretreatment variable predictive of a PSA response was the PSA doubling time (PSADT). The mean PSADT in responders was 12.7 months versus 7.5 months in nonresponders (P = 0.037). Moreover, PSADT was the only statistically significant variable on univariate analysis of PSA failure-free survival in responders (hazard ratio 0.202, 95% confidence interval 0.041 to 0.990, P = 0.049). No statistically significant difference was found in cancer-specific survival between responders and nonresponders (P = 0.1501).

CONCLUSIONS

The PSADT predicted both the response and the duration of the response to deferred antiandrogen therapy in patients diagnosed with AIPC.

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.