The assessment of treatment outcomes in metastatic prostate cancer: changing endpoints

Radium-223 (Xofigo) with concurrent abiraterone or enzalutamide: predictive biomarkers of improved overall survival in a clinically advanced cohort

PURPOSE

Radium-223 (Xofigo) is the first therapy with bone tropism for metastatic castrate-resistant prostate cancer (mCRPC) that has been shown to improve overall survival (OS). Although radium-223 has a positive effect on OS in men with mCRPC, there has been a paucity of reports from community practitioners, especially with regard to concurrent abiraterone and enzalutamide therapy. Significant differences in patient characteristics encountered may exist.

PATIENTS AND METHODS

We conducted a retrospective study of men with mCRPC who received at least 1 cycle of radium-223 (n = 35). Baseline pain and ECOG PS as well as concurrent usage of abiraterone or enzalutamide were recorded. Side effect profiles for each patient throughout treatment were noted.

RESULTS

Baseline cohort characteristics include a median age of 75 years. 37% had an ECOG PS ≥ 2 and 23% reported severe pain at baseline. 31% received concomitant enzalutamide 31% concomitant abiraterone. Patients treated concurrently with either abiraterone or enzalutamide did not display additional toxicity. Median cohort OS was 10 months. Patients with no or mild pain had longer median OS than those with moderate or severe pain, 14 versus 7 months (P = 0.028). Patients with ECOG PS < 2 had longer median OS than those with ECOG PS ≥ 2, 13 versus 10 months (P = 0.0233).

CONCLUSION

This study highlights key differences in patient characteristics encountered by community practitioners. In this population, which presented with clinically advanced disease, there was an improved survival benefit for those treated earlier in their disease. Radium-223 was well tolerated and concurrent treatment with abiraterone or enzalutamide did not add additional toxicity. These 2 points seem to advocate for aggressive and early treatment of patients with radium-223 in the community.

Serum miRNA-21: elevated levels in patients with metastatic hormone-refractory prostate cancer and potential predictive factor for the efficacy of docetaxel-based chemotherapy

BACKGROUND

miR-21 has been recognized as an "onco-microRNA" with the activity of negatively modulating the expression of tumor-suppressor genes. However, its role in prostate cancer (CaP) has not been well-documented. We designed this study to assess the potential function of serum miR-21 in the progression of CaP.

METHODS

Serum samples of 56 patients, including 20 patients with localized CaP, 20 with androgen-dependent prostate cancer (ADPC), 10 with hormone-refractory prostate cancer (HRPC), and 6 with benign prostatic hyperplasia (BPH), were collected for the measurement of miR-21. The 10 HRPC patients were administered docetaxel-based chemotherapy. Quantification of miR-21 was assayed by specific TaqMan qRT-PCR.

RESULTS

Serum miR-21 level was found to correlate to serum PSA level in patients with ADPC and HRPC, P = 0.012 and 0.049, respectively. There was no significant difference in serum miR-21 level between BPH, localized CaP and ADPC with PSA level <4 ng/ml. Higher levels of miR-21 were detected in patients with HRPC and ADPC with PSA level >4 ng/ml. Six of the 10 HRPC patients reached partial remission with a decreased PSA level of >50% after chemotherapy. Serum miR-21 levels were higher in patients who were resistant to docetaxel-based chemotherapy when compared to those sensitive to chemotherapy, P = 0.032.

CONCLUSIONS

Serum miR-21 levels are elevated in HRPC patients, especially in those resistant to docetaxel-based chemotherapy. It may be applicable as a marker to indicate the transformation to hormone refractory disease, and a potential predictor for the efficacy of docetaxel-based chemotherapy.

Progression-free survival as a predictor of overall survival in men with castrate-resistant prostate cancer

PURPOSE

To explore whether progression-free survival (PFS) or biochemical PFS can be used as a predictor of overall survival (OS) and to investigate the dependence between PFS and OS in men with castrate-resistant prostate cancer.

PATIENTS AND METHODS

Data from nine Cancer and Leukemia Group B trials that enrolled 1,296 men from 1991 to 2004 were pooled. Men were eligible if they had prostate cancer that had progressed during androgen deprivation therapy and did not receive prior treatment with chemotherapy, immunotherapy, or other nonhormonal therapy. Landmark analyses of PFS at 3 and 6 months from randomization/registration were performed to minimize lead time bias. The proportional hazards model was used to assess the significance effect of PFS rate at 3 and at 6 months in predicting OS. In addition, biochemical progression using the definitions of Prostate-Specific Antigen Working Group (PSAW) Criteria PSAWG1 and PSAWG2 were analyzed as time-dependent covariates in predicting OS.

RESULTS

The median survival time among men who experienced progression at 3 months was 9.2 months (95% CI, 8.0 to 10.0 months) compared with 17.8 months in men who did not experience progression at 3 months (95% CI, 16.2 to 20.4 months; P < .0001). Compared with men who did not progress at 3 and at 6 months, the adjusted hazard ratios for death were 2.0 (95% CI, 1.7 to 2.4; P < .001) and 1.9 (95% CI, 1.6 to 2.4; P < .001) for men who experienced progression at 3 and 6 months, respectively. In addition, biochemical progression at 3 months predicted OS. The association between PFS and OS was 0.30 (95% confidence limits = 0.26, 0.32).

CONCLUSION

PFS at 3 and 6 months and biochemical progression at 3 months predict OS. These observations require prospective validation.

Pain predicts overall survival in men with metastatic castration-refractory prostate cancer

PURPOSE

Pain from castration-refractory prostate cancer (CRPC) bone metastases is a common event. Although it is assumed that pain represents an adverse prognostic factor, this variable has not been extensively evaluated. The objective of this study was to determine whether men with CRPC who had higher pain interference scores at baseline had worse clinical outcomes compared with men who had lower pain scores.

PATIENTS AND METHODS

Data from three randomized phase III multicenter trials conducted by the Cancer and Leukemia Group B from 1992 to 1998 were combined. Eligible patients had progressive CRPC adenocarcinoma of the prostate, an Eastern Cooperative Oncology Group performance status of 0 to 2, and adequate hematologic, renal, and hepatic functions. Seven items from the Brief Pain Inventory were used to assess the impact of pain on a range of daily activities and quality of life, each rated on a scale from 0 to 10.

RESULTS

In 599 men, the median pain interference scores was 17 (interquartile range, 4 to 34), and 38% of the men had opioid analgesic use at baseline. There was a statistically significant association between pain interference scores and risk of death. The median survival times were 17.6 months (95% CI, 16.1 to 19.1 months) and 10.2 months (95% CI, 8.6 to 11.3 months; P < .001) in men with low (< 17) and high (>or= 17) pain scores, respectively. Pain was inversely associated with likelihood of prostate-specific antigen decline, objective response, and time to bone progression.

CONCLUSION

This analysis demonstrates that pain is a statistically significant predictor of overall survival in men with metastatic CRPC. These results need to be validated prospectively in future phase III trials.

Fluorodeoxyglucose positron emission tomography as an outcome measure for castrate metastatic prostate cancer treated with antimicrotubule chemotherapy

PURPOSE

Standard imaging studies are limited as outcome measures for patients with metastatic prostate cancer. We tested the hypothesis that serial fluorodeoxyglucose positron emission tomography (FDG-PET) scans can serve as an outcome measure for patients with castrate metastatic prostate cancer treated with antimicrotubule chemotherapy.

EXPERIMENTAL DESIGN

FDG-PET scans were done at baseline, 4, and 12 weeks of treatment. The average maximum standardized uptake value (SUVmaxavg) was measured in up to five lesions and was tested as the quantitative outcome measure. Prostate-specific antigen (PSA) at 4 weeks and PSA, bone scan, and soft tissue imaging at 12 weeks were considered standard outcome measures. The change in SUVmaxavg that distinguished clinically assessed progression from nonprogression was sought.

RESULTS

Twenty-two PET scans were reviewed and compared with PSA at 4 weeks; 18 PETs were compared at 12 weeks with standard outcome measures. Applying the PSA Working Group Consensus Criteria guideline that a 25% PSA increase constitutes progression to the SUVmaxavg, PET correctly identified the clinical status of 20 of 22 patients (91%) at 4 weeks and 17 of 18 patients at 12 weeks (94%). The accuracy of PET could be further optimized if a >33% increase in PSA and SUVmaxavg were used to define progression.

CONCLUSION

FDG-PET is promising as an outcome measure in prostate cancer. As a single modality, it can show treatment effects that are usually described by a combination of PSA, bone scintigraphy, and soft tissue imaging. Preliminarily, a >33% increase in SUVmaxavg or the appearance of a new lesion optimally dichotomizes patients as progressors or nonprogressors.

Randomized Phase II trial assessing estramustine and vinblastine combination chemotherapy vs estramustine alone in patients with progressive hormone-escaped metastatic prostate cancer

Based on the results of combined data from three North American Phase II studies, a randomised Phase II study in the same patient population was performed, using combination chemotherapy with estramustine phosphate (EMP) and vinblastine (VBL) in hormone refractory prostate cancer patients. In all, 92 patients were randomised into a Phase II study of oral EMP (10 mg kg day continuously) or oral EMP in combination with intravenous VBL (4 mg m² week for 6 weeks, followed by 2 weeks rest). The end points were toxicity and PSA response in both groups, with the option to continue the trial as a Phase III study with time to progression and survival as end points, if sufficient responses were observed. Toxicity was unexpectedly high in both treatment arms and led to treatment withdrawal or refusal in 49% of all patients, predominantly already during the first treatment cycle. The mean treatment duration was 10 and 14 weeks, median time to PSA progression was 27.2 and 30.8 weeks, median survival time was 44 and 50.9 weeks, and PSA response rate was only 24.6 and 28.9% in the EMP/VBL and EMP arms, respectively. There was no correlation between PSA response and survival. While the PSA response in the patients tested was less than half that recorded in the North American studies, the toxicity of EMP monotherapy or in combination with VBL was much higher than expected. Further research on more effective and less toxic treatment strategies for hormone refractory prostate cancer is mandatory.

A randomized study comparing epirubicin in a 4-weekly versus a weekly intravenous regimen in patients with metastatic, hormone resistant, prostatic carcinoma: effects on health related quality of life

The treatment of hormone resistant prostate cancer) with epirubicin 25 mg/m(2)(Epi25) on a weekly intravenous regimen may be better in terms of health related quality of life (HRQOL) than with 100 mg/m(2)(Epi100) on a 4-weekly regimen. A total of 79 patients who filled out the EORTC-QLQ-C30 questionnaire for the assessment of HRQOL could be evaluated. Compared with the baseline, no changes in HRQOL function scales or significant changes in the following HRQOL symptom scales were found. The Epi25 group reported less pain during the first 3 months and the Epi100 group more dyspnoea after 4 weeks and less pain and less insomnia but more loss of appetite after 8 weeks. In both groups, toxicity was comparable, except for World Health Organisation grade II-III alopecia occurring in 82% in the Epi100 versus 31% in the Epi25 group. There were no significant differences between groups in response rates and survival. In this study, HRQOL was not improved which is in line with other studies using only epirubicine. Epirubicin as single agent therapy should not be used in future treatment of patients with HRPC.

Effects of docetaxel on pain due to metastatic androgen-independent prostate cancer

Bone pain commonly plagues patients with metastatic androgen-independent prostate cancer. Studies of mitoxantrone demonstrated that chemotherapy can substantially reduce this debilitating symptom. Two of the available studies examining the use of docetaxel with and without estramustine for treatment of androgen-independent prostate cancer include a detailed prospective analysis of pain and quality of life. One study required patients to have pain at entry and demonstrated significant improvement in pain. The second study enrolled patients with low prevalence and intensity of pain and did not demonstrate pain relief. The available results, although preliminary, suggest that patients with significant bone pain due to androgen-independent prostate cancer can experience substantial pain relief with docetaxel-based therapy. Larger randomized studies targeting patients with sufficient prevalence and intensity of pain are needed to refine our understanding of the contribution of docetaxel to pain control in this patient population.

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.

Treatment of advanced prostate cancer

OBJECTIVES

To review the management of advanced prostate cancer, including symptom management, hormonal therapy, and the use of chemotherapy.

DATA SOURCES

Published articles and book chapters on advanced prostate cancer.

CONCLUSIONS

Advanced prostate cancer is a common problem that has a significant impact on the patient's quality of life. Multiple complications may develop during the course of the disease. Treatment may include local and systemic approaches. Advances in disease treatment include hormonal therapies and chemotherapy. Additional research is needed to determine the optimal treatment for these men.

IMPLICATIONS FOR NURSING PRACTICE

Patient education is crucial to the management of advanced prostate cancer in all practice settings. Early and prompt recognition of disease complications will enhance the patient's quality of life.

Low doses of oral dexamethasone for hormone-refractory prostate carcinoma

BACKGROUND

Although glucocorticoids have been used to treat patients with hormone-refractory prostate carcinoma (HRPC), reports have varied regarding the types and doses of glucocorticoids used as well as their clinical benefits. In the current study, low doses of dexamethasone were investigated for their specific beneficial effects and the feasibility of long term treatment.

METHODS

Thirty-seven patients diagnosed with HRPC were treated with oral dexamethasone (0.5-2 mg/day). The patients ranged in age from 53-89 years (median, 74 years). Thirty-two patients, including 6 with lymph node metastases, had bone involvement whereas only 5 patients were found to have elevated serum prostate specific antigen (PSA) levels.

RESULTS

Twenty-three patients (62%) who received no other concomitant therapy demonstrated a decline in their serum PSA level of > or = 50%, which was confirmed by a second PSA value obtained > or = 4 weeks later. The median time to PSA progression was 9 months. Among 18 patients with bone pain, 11 (61%) had improvement and in 5 patients (28%) the pain became stable. Among 21 patients with interpretable bone scans, 4 (19%) showed improvement and 8 (38%) achieved stable disease. Both symptomatic and objective responses of bone metastases were correlated with declines in the serum PSA level of > or = 50%. Ten patients achieved an increase in their hemoglobin level of at least 2 g/dL. Patients whose PSA level declined by > or = 50% with therapy had significantly prolonged survival (median, 22 months). As pretreatment markers, a longer interval before the initial evidence of disease progression appeared was found to correlate significantly with posttherapy PSA declines of > or = 75%. All side effects of the glucocorticoids were reported to be mild.

CONCLUSIONS

Low doses of dexamethasone were found to be beneficial in the treatment of HRPC, decreasing the severity of anemia and osseous disease as well as reducing serum PSA levels. A posttherapy serum PSA decline of > or = 50% appears to be a reliable marker of improved survival with this therapy.

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.

Exposure to hyperbaric oxygen induces cell cycle perturbation in prostate cancer cells

Cell cycle synchronization of tumor cells by exposure to hyperbaric oxygenation (HBO) may increase the efficacy of chemotherapy or radiation by placing cells into a chemosensitive portion of the cycle. The purpose of the current study was to examine oxygen pressure-dependent relationships with respect to the cell cycle in prostate tumor cells in vitro. LNCaP cells were grown in an incubator at 21% O2 and then exposed to 100% oxygen at pressures up to 6 atmospheres (atm) for 1.5 h. Cells were then returned to the incubator and evaluated for DNA content by propidium iodide and new DNA synthesis with a pulse-chase experiment. Cell cycle effects were evaluated by flow cytometry. Exposure to HBO increased the percentage of cells synthesizing new DNA in a dose-dependent fashion: 0 atm, 44%; 6 atm, 65%. Cells that synthesize new DNA accumulate in G2/M as a function of partial pressure of oxygen. These results suggest that HBO induces cells to enter the cell cycle and accumulate in G2/M. Cell cycle synchronization and entry of senescent cells into the cell cycle suggest that HBO may be a useful adjuvant to chemotherapy or radiation in the treatment of prostate cancer. There are two potential mechanisms of action that may make HBO efficacious in the treatment of prostate cancer. HBO may potentiate cancer chemotherapeutic agents that cause damage to DNA during DNA synthesis or HBO may inhibit cell division causing accumulation in G2/M.

Evolving strategies of cytotoxic chemotherapy for advanced prostate cancer

Despite the use of cytotoxic chemotherapy for advanced prostate cancer for half a century, its clinical utility in this setting remains undefined. Based on traditional methods of assessment, the list of the most active cytotoxic agents includes cyclophosphamide, doxorubicin, mitoxantrone and cisplatin. With the introduction of more structured methods of assessment, including careful assessment of indices of quality of life and serial measurement of serum prostate-specific antigen (PSA), the role of cytotoxic agents is being re-assessed. In view of the cell cycle characteristics of prostate cancer, there appears to be an emerging role for combination inhibitors of mitosis, including estramustine in combination with the vinca alkaloids, etoposide or paclitaxel.