Prognostic significance of extent of disease in bone in patients with androgen-independent prostate cancer

Percentage of the positive area of bone metastasis is an independent predictor of disease death in advanced prostate cancer

We addressed in this study whether quantifying the extent of disease on bone scans can predict the disease death of patients with advanced prostate cancer using computer-assisted image analysis. Pretreatment radionuclide bone scans were reviewed in 56 patients with bone metastases from prostate cancer, and the percentage of the positive area on a bone scan (%PABS) was quantified automatically using a personal computer with the NIH Image program for estimation of the accurate extent of metastatic bone lesions on a bone scan. The significance of the %PABS as well as the other known prognostic factors was evaluated using univariate and multivariate Cox proportional hazards analysis. In univariate regression analysis, the %PABS (P=0.0155), serum alkaline phosphatase (P=0.0272), the tumour grade based on biopsy (P=0.044) and the number of bone lesions on bone scans (P=0.0388) were well associated with disease-specific survival. In multivariate analysis, the %PABS (P=0.0155, relative risk ratio 2.603), but not the other factors, was the independent predictor of the disease death. These results suggest that the %PABS is a novel parameter for predicting the prognosis of patients with advanced prostatic cancer.

Nomogram for overall survival of patients with progressive metastatic prostate cancer after castration

PURPOSE

To develop a pretreatment prognostic model for survival of patients with progressive metastatic prostate cancer after castration using parameters that are measured during routine clinical management.

PATIENTS AND METHODS

Pretreatment clinical and biochemical determinants from 409 patients enrolled onto 19 consecutive therapeutic protocols from June 1989 through January 2000 were evaluated. The factors selected were age, Karnofsky performance status (KPS), hemoglobin (HGB), prostate-specific antigen (PSA), lactate dehydrogenase (LDH), alkaline phosphatase (ALK), and albumin. These factors were combined in an accelerated failure time regression model to produce a nomogram to predict median, 1-year, and 2-year survival. The nomogram was validated internally and externally using data from a multicenter randomized trial of suramin plus hydrocortisone versus hydrocortisone alone.

RESULTS

The median survival of the entire group was 15.8 months (range, 0.9 to 77.8 months); 87% have died. In multivariable analysis, KPS, HGB, ALK, albumin, and LDH were significantly associated with survival (P <.05), whereas age and PSA were not. All seven factors were included in the nomogram. When applied to the external validation data set, the nomogram achieved a concordance index of 0.67. Calibration plots suggested that the nomogram was well calibrated for all predictions.

CONCLUSION

A nomogram derived from pretreatment parameters that are measured on a routine basis was constructed. It can be used to predict the median, 1-year, and 2-year survival of patients with progressive castrate metastatic disease with reasonable accuracy. The information is useful to assess prognosis, guide treatment selection, and design clinical trials.

Chemotherapy for prostate cancer

Androgen deprivation therapy remains the mainstay of therapy for patients with advanced prostate cancer and for selected patients with localized prostate cancer. Androgen deprivation therapy is the model of target-based therapies in this disease. Although it is clear that other target-based therapies need to be developed, cytotoxic chemotherapy is emerging as an effective form of treatment for men with prostate cancer. The early studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic hormone-refractory prostate cancer with minimal toxicity, and significant palliation could be provided. Since then, it has been recognized that estramustine, when combined with a variety of microtubular inhibitors, is very active in hormone-refractory prostate cancer. Doublets combining estramustine plus a taxane seem to be the most active. Although it appears that estramustine may add some activity to taxanes, the mechanism of its activity is uncertain, and its overall value is similarly questioned, particularly in light of its significant toxicity. Regimens that omit estramustine are being explored (ie, either taxane alone or taxane plus biologic agents). In addition, triplet therapy (combining estramustine plus a taxane plus a third drug, such as carboplatin or etoposide) is being explored. Finally, the utility of chemotherapy is beginning to be explored in the context of earlier disease in the neoadjuvant, adjuvant, or serologically relapsing group of patients. Data from these studies are just beginning to be gathered.

Plasma osteopontin: associations with survival and metastasis to bone in men with hormone-refractory prostate carcinoma

BACKGROUND

Osteopontin (OPN) is a secreted glycoprotein that is detectable in human body fluids. Its increased expression has been found in many malignancies, and a stimulatory effect on human prostate carcinoma cells in vitro has been demonstrated. Plasma OPN levels have been associated with tumor burden and survival in patients with metastatic breast carcinoma. The authors explored these associations in men with hormone-refractory prostate carcinoma (HRPC).

METHODS

Plasma samples from 100 men with HRPC were collected. OPN was measured using an antigen-capture enzyme-linked immunosorbent assay technique. Multivariable analyses were performed to identify predictors of OPN and survival.

RESULTS

At the time of OPN sampling, the median patient age was 73 years (range, 50-86 years), and 92% of patients had metastases. The median plasma OPN level was 198.5 ng/mL (range, 15.0-2363.0 ng/mL), the median prostate specific antigen level was 67.8 microg/L (range, 0.1-7550.0 microg/L), and the median survival was 13.7 months. OPN plasma levels were higher in patients with versus patients without bone metastases (P = 0.024). Multivariable modeling demonstrated an independent association of the OPN level with alkaline phosphatase, hemoglobin, and creatinine levels. The log-transformed OPN level (hazard ratio [HR], 2.38; P < 0.0001), performance status (HR, 2.43; P = 0.007), and a history of prior radiotherapy for localized prostate carcinoma (HR, 0.48; P = 0.0229) were independent predictors of survival in a Cox multivariate model.

CONCLUSIONS

In this study, in men with established HRPC, the plasma OPN level was associated with the presence of metastases to bone and with other measures of tumor burden, and it was correlated independently and negatively with survival.

Clinical predictors of androgen-independent prostate cancer and survival in the prostate-specific antigen era

OBJECTIVES

To further characterize and identify novel predictors of androgen-independent prostate cancer (AIPC) and survival in the prostate-specific antigen (PSA) era.

METHODS

A total of 184 consecutive patients with prostate cancer receiving chronic androgen suppression were assessed for the development of AIPC and overall survival.

RESULTS

The median time to development of AIPC was 44 months (Stage M+ = 24 months; Stage M0 = 63 months, P = 0.000001). The 10-year overall survival rate for Stage M0 or M+ disease was 89% and 55%, respectively. AIPC developed significantly more commonly in patients with a higher nadir PSA level (greater than 1 ng/dL), a longer time to reach nadir PSA (greater than 3 months), a larger body mass index (greater than 27 kg/m2), greater pretherapy PSA level, and when evidence of metastatic disease was identified (logistic regression analysis). Overall survival was significantly associated with advanced stage (skeletal metastases), pretreatment PSA level, and history of skeletal fracture (multivariate Cox regression analysis).

CONCLUSIONS

In the PSA era, longer intervals of androgen suppression therapy in nonmetastatic, biochemically recurrent prostate cancer have translated into a change in the duration of androgen-dependent prostate cancer. Although the duration of androgen dependence remains variable, prolonged--possibly "curative"--control exists in a subset of patients. Obese men developed AIPC significantly sooner than did slender men. A skeletal fracture was a significant negative predictor of overall survival. These observations form the basis for nomogram predictions of AIPC in the PSA era.

The treatment challenge of hormone-refractory prostate cancer

BACKGROUND

Both the demographics and treatment of hormone-refractory prostate cancer (HRPC) are changing. Patients are younger and healthier, with fewer comorbidities. The "no treatment until symptoms" approach is disappearing. Chemotherapy is increasingly being utilized.

METHODS

The authors review the steps involved in hormone management before chemotherapy is considered. The roles for chemotherapy in current clinical trials are examined.

RESULTS

Effective hormonal management of the prostate cancer patient incorporates an understanding of the stages of hormone sensitivity and prescribing additional interventions beyond simple castration. Once hormone refractoriness is established, the combination of mitoxantrone and prednisone has become a standard chemotherapeutic approach. New agents such as docetaxel are being tested in phase III trials against mitoxantrone plus prednisone.

CONCLUSIONS

HRPC is now regarded as a chemotherapy-sensitive tumor. The goals of chemotherapy in HRPC are to decrease PSA level and improve quality of life. New agents and combinations are needed to improve survival.

Dual X-ray absorptiometry detects disease- and treatment-related alterations of bone density in prostate cancer patients

Metastatic bone disease is an important clinical problem which has proven difficult to study because of a lack of noninvasive investigative modalities. Here we show that dual-energy X-ray absorptiometry (DXA) scanning provides clinically useful information about the status of metastatic bone lesions in cancer patients undergoing palliative treatment. In the study group of 21 patients, a significant increase in metastatic bone mineral density (BMD) was confirmed in prostate (n = 14) relative to breast (n = 7) cancer patients. With respect to the prostate cancer cohort, further increases in lesional BMD were evident in all evaluable patients in whom biochemical progression occurred; conversely, lesional BMD declined in patients who had a partial response to therapy. BMD of uninvolved bone decreased with all types of androgen-deprivation therapy regardless of whether patients responded or relapsed. We conclude that BMD changes in both lesional and uninvolved bone are readily detectable in metastatic prostate cancer, and propose that DXA scanning represents a promising new approach to monitoring the natural history and therapeutic course of this disease.

Bone-targeted therapy for advanced androgen-independent carcinoma of the prostate: a randomised phase II trial

BACKGROUND

Prostate carcinoma is linked to osteoblastic metastasis. We therefore investigated the value of bone-targeted consolidation therapy in selected patients with advanced androgen-independent carcinoma of the prostate.

METHODS

103 patients received induction chemotherapy, consisting of ketoconazole and doxorubicin alternating with estramustine and vinblastine. After two or three cycles of induction chemotherapy, we randomly assigned 72 patients who were clinically stable or responders to receive doxorubicin with or without strontium-89 (Sr-89) every week for 6 weeks.

FINDINGS

Overall 62 of the 103 (60%, 95% CI 50-70) patients had a 50% or greater reduction in serum prostate-specific antigen concentration that was maintained for at least 8 weeks, and 43 (42%, 32-52) had an 80% or greater reduction. 49 (52%) patients with bone pain at registration had complete resolution of pain. After follow-up of 67 patients until death, the estimated median survival for all 103 patients was 17.5 months (range 0.5-37.7). For the 36 patients randomly assigned to receive Sr-89 and doxorubicin, the median survival time was 27.7 months (4.9-37.7), and for the 36 who received doxorubicin alone it was 16.8 months (4.4-34.2) (p=0.0014). The hazard ratio was 2.76 (95% CI 1.44-5.29).

INTERPRETATION

Bone-targeted consolidation therapy consisting of one dose of Sr-89 plus doxorubicin once a week for 6 weeks, when given to patients with stable or responding advanced androgen-independent carcinoma of the prostate after induction chemotherapy, improved overall survival.

Paclitaxel, estramustine phosphate, and carboplatin in patients with advanced prostate cancer

PURPOSE

To determine the safety and activity of weekly paclitaxel in combination with estramustine and carboplatin (TEC) in patients with advanced prostate cancer.

PATIENTS AND METHODS

In a dose-escalation study, patients with advanced prostate cancer were administered paclitaxel (weekly 1-hour infusions of 60 to 100 mg/m(2)), oral estramustine (10 mg/kg), and carboplatin (area under the curve, 6 mg/mL-min every 4 weeks). Paclitaxel levels were determined 0, 30, 60, 90, and 120 minutes and 18 hours after infusion, and a concentration-time curve was estimated. Once a safe dose was established, a multi-institutional phase II trial was conducted in patients with progressive androgen-independent disease.

RESULTS

Fifty-six patients with progressive androgen-independent disease were treated for a median of four cycles. The dose of paclitaxel was escalated from 60 to 100 mg/m(2) without the occurrence of DLT. Posttherapy decreases in serum prostate-specific antigen levels of 50%, 80%, and 90% were seen in 67%, 48%, and 39% (95% confidence interval, 55% to 79%, 35% to 61%, 26% to 52%) of the patients, respectively. Of the 33 patients with measurable disease, two (6%) had a complete response and 13 (39%) had a partial response. The overall median time to progression was 21 weeks, and the median survival time for all patients was 19.9 months. Major grade 3 or 4 adverse effects were thromboembolic disease (in 25% of patients), hyperglycemia (in 38%), and hypophosphatemia (in 42%). Significant leukopenia, thrombocytopenia, and peripheral neuropathy were not observed.

CONCLUSION

TEC has significant antitumor activity and is well tolerated in patients with progressive androgen-independent prostate cancer.

Chemotherapy for androgen- independent prostate cancer: myth or reality

In the past, the treatment options for patients with metastatic prostate cancer that progressed despite castrate levels of testosterone was limited, and no therapies provided an improvement in survival. The majority of these patients had extensive osseous disease, multiple comorbidities, and poor performance status. With the widespread use of prostate-specific antigen (PSA) to monitor their clinical course, patients have presented with less extensive disease and a better performance status. Clinical trial methodology has improved as well, through incorporation of post-therapy changes in PSA to evaluate novel agents. This approach allows more patients to enter clinical trials, and the results show that the majority of these patients will have significant reduction in pain, regression of measurable disease, and suppression of PSA. These data suggest that prostate cancer is not as resistant to chemotherapy as it was once thought to be.

Chemotherapy for patients with advanced prostate carcinoma: a new option for therapy

BACKGROUND

Prostate carcinoma is the second leading cause of cancer-related death in men in the United States. In nearly all of these men, cancer progressed despite initial treatment with androgen ablation therapy. Managing hormone-refractory prostate carcinoma remains a difficult challenge for the clinician. In the past, cytotoxic chemotherapy was considered inactive, but recent advances have altered this view significantly.

METHODS

A MEDLINE review of recent studies of chemotherapy in hormone-refractory prostate carcinoma was performed.

RESULTS

Benefit of treatment may now be measured by prostate specific antigen as a marker of antitumor activity, quality of life and pain scores, and traditional objective measures of response. The antiandrogen withdrawal syndrome and secondary hormonal therapies are important treatment options that usually precede chemotherapy. New drug combinations are demonstrating promising levels of efficacy and proven palliative ability. Two large randomized trials have shown that mitoxantrone in combination with steroids is more effective in improving pain and quality of life than steroids alone. In several Phase II studies, estramustine combinations with vinblastine, etoposide, paclitaxel, or docetaxel produced significant responses in over 50% of patients. Future research will define optimal chemotherapy combinations and test new agents. In addition, systemic chemotherapy is being investigated in earlier stages of prostate carcinoma at high risk for progression.

CONCLUSIONS

Cytotoxic chemotherapy has demonstrated clear activity and palliative benefit in patients with hormone-refractory prostate carcinoma. Its role in managing advanced prostate carcinoma patients is growing but remains an area of active investigation.

An update on prostate cancer research

The pathogenesis of prostate cancer reflects complex interactions among environmental and genetic factors. Recent advances suggest molecular mechanisms that may explain geographic and ethnic variations in prostate cancer incidence, and understanding of molecular disease progression is advancing rapidly. Clinically, the case for screening has become stronger, and declining prostate cancer mortality rates may be due in part to early detection and treatment. Improved risk assessment for patients with localized disease is now available, although further refinement in predictive algorithms will need to incorporate validated molecular prognostic markers. Treatment options for patients with localized prostate cancer have expanded and the role of androgen deprivation further delineated. Finally, treatment strategies for patients with androgen-independent disease have also expanded, although novel therapies are required to improve survival in this group of patients.

New treatment strategies in advanced prostate cancer

The treatment of advanced prostate cancer has evolved rapidly in the last 5 years. Therapeutic options for patients with advanced disease, once essentially limited to the use of androgen deprivation, have expanded to include a number of interventions, including secondary hormonal manipulations, chemotherapy, and a variety of investigational approaches. Novel therapeutic approaches in prostate cancer patients are likely to be undertaken in patients with disease that is at or below the limits of detection by current imaging technology, so novel methods will be essential to the successful evaluation and use of these agents.