Adjunctive therapy for men with high risk localized and locally advanced prostate cancer: targeting disseminated tumor cells

Squalamines in Blockade of Tumor-Associated Angiogenesis and Cancer Progression

Mechanisms of action of squalamine in human vascular endothelial cells indicate that this compound attaches to cell membranes, potentially interacting with calmodulin, Na+/H+ exchanger isoform NHE3 and other signaling pathways involved in the angiogenic process. Thus, squalamine elicits blockade of VEGF-induced endothelial tube-like formation in vitro. Further, squalamine reduces growth of several preclinical models of human cancers in vivo and acts to stop metastatic tumor spread, actions due largely to blockade of angiogenesis induced by the tumor and tumor microenvironment. Squalamine in Phase I/II trials, alone or combined with standard care, shows promising antitumor activity with limited side-effects in patients with advanced solid cancers. Increased attention on squalamine regulation of signaling pathways with or without combination treatments in solid malignancies deserves further study.

Synthesis and Biological Activities of Naturally Functionalized Polyamines: An Overview

Recently, extensive researches have emphasized the fact that polyamine conjugates are becoming important in all biological and medicinal fields. In this review, we will focus our attention on natural polyamines and highlight recent progress in both fundamental mechanism studies and interests in the development and application for the therapeutic use of polyamine derivatives.

Squalamine blocks tumor-associated angiogenesis and growth of human breast cancer cells with or without HER-2/neu overexpression

Angiogenesis is critical for breast cancer progression. Overexpression of HER-2/neu receptors occur in 25-30% of breast cancers, and treatment with trastuzumab inhibits HER-2-overexpressing tumor growth. Notably, HER-2-mediated signaling enhances vascular endothelial growth factor (VEGF) secretion to increase tumor-associated angiogenesis. Squalamine (aminosterol compound) suppresses VEGF-induced activation of kinases in vascular endothelial cells and inhibits tumor-associated angiogenesis. We assessed antitumor effects of squalamine either alone or with trastuzumab in nude mice bearing breast tumor xenografts without (MCF-7) or with HER2-overexpression (MCF-7/HER-2). Squalamine alone inhibited progression of MCF-7 tumors lacking HER2 overexpression, and squalamine combined with trastuzumab elicited marked inhibition of MCF-7/HER2 growth exceeding that of trastuzumab alone. MCF-7/HER-2 cells secrete higher levels of VEGF than MCF-7 cells, but squalamine elicited no growth inhibition of either MCF-7/HER-2 or MCF-7 cells in vitro. However, squalamine did stop growth of human umbilical vein endothelial cells (HUVECs) and reduced VEGF-induced endothelial tube-like formations in vitro. These effects correlated with blockade of focal adhesion kinase phosphorylation and stress fiber assembly in HUVECs. Thus, squalamine effectively inhibits growth of breast cancers with or without HER-2-overexpression, an effect due in part to blockade of tumor-associated angiogenesis.

Pilot trial of adjuvant paclitaxel plus androgen deprivation for patients with high-risk prostate cancer after radical prostatectomy: results on toxicity, side effects and quality-of-life

Therapeutic strategy remains unclear with no clear consensus for men with high-risk prostate cancer (PCa) after radical prostatectomy. We aimed to evaluate into a prospective randomized trial the effectiveness and feasibility of adjuvant weekly paclitaxel combined with androgen deprivation therapy (ADT) in these patients. A total of 47 patients with high-risk PCa were randomized 6 weeks after radical prostatectomy: ADT alone versus combination of ADT and weekly paclitaxel. Toxicity, quality-of-life and functional results were compared between the two arms. All 23 patients completed eight cycles of paclitaxel. Toxicity was predominantly of grade 1-2 severity. There were no differences in EORTC QLQ-C30 scores between the two groups and between baseline and last assessment at 24 months after surgery. Urinary continence was complete at 1 year after surgery for all patients and no significant differences were noted at each assessment between the two groups. The interim analysis of this trial confirms the feasibility of weekly paclitaxel in combination with ADT in men at high-risk PCa with curative intent. This adjuvant combined therapy does not alter quality-of-life and continence recovery after surgery plus ADT. A larger cohort is awaited to determine the oncological outcomes of this strategy.

Surgical management of high risk prostate cancer: the Mayo Clinic experience

Although the prostate specific antigen (PSA) era has altered the clinical and demographic characteristics of men with newly-diagnosed prostate cancer, the impact on patients with high risk disease has been less predictable. We have long advocated aggressive surgical resection for patients with high risk prostate cancer at the Mayo Clinic, including patients with clinical T3 tumors, and have reported our results as well of radical prostatectomy with adjuvant hormonal therapy in the setting of lymph node positive disease. At the same time, multiple predictive models have been developed to assess the risk of disease progression following definitive therapy for prostate cancer. One such model is pretreatment risk group stratification, based on patients' PSA at diagnosis, biopsy Gleason score, and clinical stage. Here, we will review our institution's experience with surgical treatment for men with high risk prostate cancer, and will address the benefits and potential pitfalls of the pretreatment risk group classification model for high risk patients.

Long-Term Outcome After Radical Prostatectomy for Patients With Lymph Node Positive Prostate Cancer in the Prostate Specific Antigen Era

PURPOSE

While the incidence of lymph node positive prostate cancer has decreased during the prostate specific antigen era, the optimal treatment of these patients remains in question. We examined the impact of lymph node metastases on the outcome of patients following radical prostatectomy and investigated prognostic factors that affect survival.

MATERIALS AND METHODS

We identified 507 men treated with radical prostatectomy between 1988 and 2001 who had lymph node positive disease. Of the 507 patients 455 (89.7%) were treated with adjuvant hormonal therapy. Median followup was 10.3 years (IQR 6.1-13.5). Postoperative survival rates were estimated using the Kaplan-Meier method and the impact of various clinicopathological factors on outcome was analyzed using Cox proportional hazard regression models.

RESULTS

Ten-year cancer specific survival for patients with positive lymph nodes was 85.8% with 56% of the men free from biochemical recurrence at last followup. On multivariate analysis pathological Gleason score 8-10 (p = 0.004), positive surgical margins (p = 0.016), nondiploid tumor ploidy (p = 0.023) and 2 or greater positive nodes (p = 0.001) were adverse predictors of cancer specific survival. Tumor stage, year of surgery and total number of nodes removed did not significantly affect outcome. Adjuvant hormonal therapy decreased the risk of biochemical recurrence (p <0.001) and local recurrence (p = 0.004) but it was not associated with systemic progression (p = 0.4) or cancer specific survival (p = 0.4).

CONCLUSIONS

Radical prostatectomy may offer long-term survival to patients with lymph node positive prostate cancer. Gleason score, margin status, tumor ploidy and the number of involved nodes predict survival, while the role of adjuvant hormonal therapy continues to be defined.

Long-term follow-up of a neoadjuvant chemohormonal taxane-based phase II trial before radical prostatectomy in patients with non-metastatic high-risk prostate cancer

OBJECTIVE

To assess the feasibility and activity of a neoadjuvant treatment combining a luteinizing hormone-releasing hormone (LHRH)-analogue, estramustine and docetaxel before radical retropubic prostatectomy (RRP) in patients with high-risk prostate cancer.

PATIENTS AND METHODS

High-risk patients were defined as clinical stage > or =T3 and/or a prostate-specific antigen (PSA) level of > or =15 ng/mL, and/or biopsy a Gleason sum of > or =8. Patients received LHRH analogue treatment until the PSA nadir (a stable PSA level for two consecutive determinations) and then, continuing hormone therapy, a combined regimen of estramustine and docetaxel. Patients had RRP within a month of completing the neoadjuvant regimen. All patients were assessed for toxicity and surgical complications. A clinical response was defined as complete (CR, the disappearance of all palpable and radiological abnormalities and a decline in PSA level of > or =90%) or partial (PR, a decline in PSA level of half or more with stable or improved palpable and/or radiological abnormalities). A pathological response was defined as 'complete' (undetectable cancer), 'substantial' (residual cancer in < or =10% of the surgical specimen) or 'minimal' (residual cancer in >10% of the surgical specimen). The biomarkers p53, bcl-2, MIB1, erbB2 and factor VIII were also evaluated.

RESULTS

Of 22 patients enrolled between March 1999 and January 2002, 21 (mean age 63 years; mean PSA level 61 ng/mL; median biopsy Gleason sum 8) completed the neoadjuvant therapy. The clinical stage was organ-confined in three patients (15%); five (25%) had pelvic lymphadenopathy on computed tomography. The neoadjuvant treatment was well tolerated, with only one grade 2 toxicity (Eastern Cooperative Oncology Group grading). All PSA values decreased by >90% from baseline after hormonal therapy only, and the mean reduction from before to after chemotherapy was statistically significant (P = 0.001). Three patients (15%) had a CR, 16 (80%) had a PR and one (5%), with sarcomatoid tumour, had progression; 19 had non-nerve-sparing RRP and there were no major complications during or after RRP. The pathological assessment showed that one patient (5%) had no tumour (pT0) and six (32%) had a 'substantial' response. The overall rate of organ-confined disease was 58%, vs a mean 8% predicted likelihood from the Kattan nomogram. Five patients (26%) had positive surgical margins and four (21%) had positive lymph nodes. At a median follow-up of 53 months, eight patients (42%) were disease-free. Organ-confined disease (P = 0.022), residual cancer at pathology in < or =10% of the surgical specimen (P = 0.007) and no seminal vesicle invasion (P = 0.001) correlated with disease-free survival.

CONCLUSION

A neoadjuvant chemohormonal regimen before RRP is feasible and active in patients with high-risk prostate cancer. The rate of pathological organ-confined disease was higher than expected and responding patients had an 85% disease-free survival rate at 5 years.