Locally advanced prostate cancer

Long-Term Followup of a Randomized Study of Locally Advanced Prostate Cancer Treated With Combined Orchiectomy and External Radiotherapy Versus Radiotherapy Alone

PURPOSE

In a randomized study we compared the combination of orchiectomy and radiotherapy to radiotherapy alone as treatment for locally advanced prostate cancer. Patients who were treated only with radiotherapy initially underwent castration therapy at clinical progression, providing the opportunity to compare immediate vs deferred endocrine intervention.

MATERIALS AND METHODS

In this prospective study 91 patients with locally advanced prostate cancer were randomized to receive external beam radiotherapy (46) or combined orchiectomy and radiotherapy (45) after surgical lymph node staging. Survival rates were calculated.

RESULTS

During 14 to 19 years of followup 87% of the patients in the radiotherapy group and 76% in the combined orchiectomy and radiotherapy group died (log rank p = 0.03). Prostate cancer mortality was 57% and 36%, respectively (log rank p = 0.02). The difference in favor of combined treatment was mainly caused by lymph node positive tumors. For node negative tumors there was no significant difference in the survival rates.

CONCLUSIONS

Immediate androgen deprivation should be considered instead of deferred endocrine treatment started at clinical progression for prostate cancer with spread to regional lymph nodes. While awaiting evidence from randomized trials, one should consider full dose radiotherapy for local control of locally advanced prostate cancer even when it is lymph node positive.

Management Strategies for Locally Advanced Prostate Cancer

Locally advanced prostate cancer represents a subpopulation of prostate cancer diagnosed in patients who are either untouched by screening efforts or whose disease has an unusually rapidly progressive natural history. The diagnostic work-up for the locally advanced patient is distinct from that of early stage disease in several respects in that it is related principally to ruling out metastases. The typical metastatic work-up consists of a serum alkaline phosphatase, bone scan, CT of the abdomen/pelvis, and chest x-ray. Once metastatic disease has been ruled out, individual components of the management of locally advanced prostate cancer patients may include surgery (palliative or curative), external beam radiation therapy (with photons or particles) or brachytherapy (with low-dose rate/permanent or high-dose rate/temporary radiation sources), and hormone therapy. Unlike in early stage disease, observation/watchful waiting is typically not a treatment option in locally advanced prostate cancer. Of the curative local control modalities, the one most commonly used, and the one which has emerged as the clinical standard, is photon external beam radiotherapy (EBRT). Numerous randomised studies have shown that androgen ablation has an established role in conjunction with radiotherapy for locally advanced disease--the current standard of care is thus photon EBRT plus neoadjuvant and adjuvant androgen ablation. Long-term androgen ablation appears to be better than short-term ablation, even when hormone complications are considered. EBRT is typically delivered to the prostate, seminal vesicles and pelvic lymph nodes, although in some circumstances local fields to the prostate and seminal vesicles may be adequate. New treatment planning and delivery techniques, such as intensity-modulated radiotherapy and organ motion tracking, are being developed to reduce the morbidity of radiotherapy while permitting a higher delivered dose. Further work is necessary to determine the precise sequencing and duration of hormone therapy in conjunction with radiotherapy and the optimum radiotherapy treatment volume. Additional work is also needed to determine the precise groups benefiting from other local control modalities such as surgery and brachytherapy. Finally, novel investigational strategies such as chemotherapy and gene therapy are being applied in an attempt to improve outcomes of locally advanced prostate cancer patients.

Hormone therapy and radiotherapy for early prostate cancer: a utility-adjusted number needed to treat (NNT) analysis

PURPOSE

To quantify, using the number needed to treat (NNT) methodology, the benefit of short-term (< or =6 months) hormone therapy adjuvant to radiotherapy in the group of patients with early (clinical stage T1-T2c) prostate cancer.

METHODS AND MATERIALS

The absolute biochemical control benefit for the use of hormones adjuvant to radiotherapy in early-stage disease was determined by literature review. A model was developed to estimate the utility-adjusted survival detriment due to the side effects of hormone therapy. The NNTs before and after the incorporation of hormone sequelae were computed; the sign and magnitude of the NNTs were used to gauge the effect of the hormones.

RESULTS

The absolute NNT analysis, based on summarizing the results of 8 reports including a total of 3652 patients, demonstrated an advantage to the addition of hormones for the general early-stage prostate cancer population as well as for all prognostic groups. After adjustment for hormone-induced functional loss, the advantage of hormones remained considerable in the high- and intermediate-risk groups, with the utility-adjusted NNT becoming weakened in the low-risk group when the utility compromise from complications of hormones was assumed to be considerable.

CONCLUSIONS

Short-term hormone therapy seems to be beneficial for selected early-stage prostate cancer patients. The advantage seems to be greatest in the intermediate- and high-risk groups; with current follow-up, the side effects of hormones may outweigh their benefit in certain clinical situations in the favorable group. The present investigation demonstrates the significant role of the NNT technique for oncologic and radiotherapeutic management decisions when treatment complications need to be considered and balanced with the beneficial effects of the treatment.

Highly specific transgene expression mediated by a complex adenovirus vector incorporating a prostate-specific amplification feedback loop

Development of novel therapeutic agents is needed to address the problems of locally recurrent, metastatic, and advanced hormone-refractory prostate cancer. We have constructed a novel complex adenovirus (Ad) vector regulation system that incorporates both the prostate-specific ARR2PB promoter and a positive feedback loop using the TRE promoter to enhance gene expression. This regulation strategy involves the incorporation of the TRE upstream of the prostate-specific ARR2PB promoter to enhance its activity with Tet regulation. The expressions of both GFP and tTA were placed under the control of these TRE-ARR2PB promoters, so that in the cells of prostate origin a positive feedback loop would be generated. This design greatly enhanced GFP reporter expression in prostate cancer cells, while retaining tight control of expression in nonprostate cancer cells, even at an MOI as high as 1000. This novel positive feedback loop with prostate specificity (PFLPS) regulation system we have developed may have broad applications for expressing not only high levels of toxic proteins in cancer cells, but alternatively could also be manipulated to regulate essential genes in a highly efficient conditionally replicative adenovirus vector specifically directed to prostate cancer cells. The PFLPS regulation system, therefore, serves as a promising new approach in the development of both a specific and effective vector for cancer gene therapy.

Inverse association between prostatic polyunsaturated fatty acid and risk of locally advanced prostate carcinoma

BACKGROUND

An effect of fatty acids has been implicated in men with advanced-stage prostate carcinoma and in men who have died of the disease. To evaluate the influence of fatty acids in men with prostate carcinoma at earlier stages, the authors examined the relation between prostatic concentrations of fatty acids and locally advanced prostate carcinoma in men with clinically organ-confined disease.

METHODS

Fatty acids were measured by capillary gas chromatography in fresh, nonmalignant prostate tissue specimens collected during surgery from 196 men undergoing radical prostatectomy for localized prostate carcinoma. Two-sided, two-sample Student t tests compared mean concentrations in men with extraprostatic disease (pT3-4N0-1M0) with control men with organ-confined disease. Logistic regression accounted for clinical stage, prostate-specific antigen level, Gleason sum, and other factors.

RESULTS

Percent total prostatic polyunsaturated fatty acid (PUFA) was found to be inversely associated with risk of locally advanced prostate carcinoma (n=52) (odds ratio [OR]=0.93, 95% confidence interval [95% CI], 0.87-0.99; P=0.035). Risk of seminal vesicle involvement accounted for this association (OR=0.86, 95% CI, 0.78-0.95; P=0.003). Percent omega-3 fatty acid (eicosapentanoic + docosahexanoic acids) and percent arachidonic acid also were found to be inversely related to the risk of seminal vesicle involvement (OR=0.52, 95% CI, 0.30-0.90; P=0.02; and OR=0.84, 95% CI,; 0.75-0.95; P=0.005, respectively).

CONCLUSIONS

Prostatic PUFA levels appear to influence the risk of locally advanced prostate carcinoma in men with clinically organ-confined disease. This association may be mediated through the immune system.

Hormone therapy adjuvant to external beam radiotherapy for locally advanced prostate carcinoma

BACKGROUND

Hormone therapy commonly is used to treat metastatic, locally advanced, and localized prostate carcinoma. The objective of the current investigation was to determine, using the number-needed-to-treat (NNT) method, the effect of using hormone therapy to treat locally advanced disease, with consideration given to both the complications and the known advantages associated with hormone therapy.

METHODS

A literature review was performed to determine 1) the absolute benefit, based on available clinical endpoints, associated with the addition of hormone therapy to external beam radiotherapy for locally advanced prostate carcinoma; 2) the incidence of side effects of short-term and long-term hormone therapy; and 3) the stepwise progression from biochemical failure to death. A model was constructed to estimate the complication/utility-adjusted survival detriment resulting from the side effects of short-term (</= 6 months) and long-term (> 6 months) hormone therapy, and the absolute/unadjusted and complication-adjusted NNTs for the addition of short-term and long-term hormone therapy were computed. In all cases, the magnitudes and signs of the NNTs obtained were used to gauge the effect of hormone therapy.

RESULTS

The unadjusted NNTs were positive and in most cases had relatively small magnitudes (the greater the NNT, the smaller the benefit) for both short-term and long-term hormone therapy; these results were expected, and they suggested that there is a strong benefit associated with the use of hormones adjuvant to radiotherapy for locally advanced disease. Adjusted NNTs remained positive and had relatively small magnitudes even after the introduction into the analysis of complications of short-term and long-term hormone therapy. This finding, although weak with respect to the effect of short-term hormone therapy on cause-specific survival, remained robust over the range of values for utility impairment expected from short-term and long-term hormone therapy.

CONCLUSIONS

The benefits of short-term and long-term hormone therapy for locally advanced prostate carcinoma appear to be significant and to outweigh the associated side effects. Long-term therapy appears to be better than short-term therapy in terms of virtually all endpoints studied, even when the increased incidence of side effects is considered. The current investigation was successful in the use of the complication-adjusted NNT method for oncologic and radiotherapeutic scenarios in which the results of randomized trials could be summarized, adjusted for treatment toxicity, and individualized to a given patient.

Early prostate cancer: clinical decision-making

Prostate cancer is one of the most common malignant diseases for which health-care intervention is sought worldwide, and in many developed countries it is the most common. Some patients with early-stage prostate cancer, especially those who are elderly and have comorbidities, can be observed without treatment. Surgery (radical prostatectomy) and radiotherapy (external-beam radiotherapy, brachytherapy, or both) are the most widely accepted curative options for patients with early-stage disease who need intervention. All these local treatments have been refined, resulting in comparable cure rates; however, they all have different side-effect profiles. Adjuvant systemic treatments (hormones or chemotherapy), which are effective for advanced-stage disease, might have a greater role in early-stage disease. Selecting the best option for individuals from the available options is challenging--the decision on whether and how to treat is based on many disease and patient factors. Here, we review the major treatment options, discuss their relative advantages and disadvantages, and provide a general approach to management of patients with early-stage prostate cancer.

Trends in clinical trials in surgical oncology: implications for outcomes research

Outcomes analysis is emerging as a crucial tool in understanding and improving health care. To this end, outcomes research is focused on methodologies for assessing the impact and quality of clinical services and the penetration of new findings. Clinical trials are an important mechanism for generating data to support outcomes research activities. In clinical trials in surgical oncology, there has been a general broadening of the spectrum of end points that are more focused on the needs of providing data to outcomes researchers. For example, in addition to traditional "mechanical" end points reflecting the physical dimensions of disability, awareness of the importance of end points related to quality of life has increased. Moreover, a variety of innovative study designs and methodologies have found more widespread use, including noninferiority trials, preresection staging designed to direct therapy more precisely, planned early reports of conditional results, prognostic studies, assessment of an event status at a point in time, and large simple trials. The goal of this article is to summarize and assess some of the trends in clinical trials in surgical oncology. Examples of ongoing studies or of trials in development from the American College of Surgeons Oncology Group are discussed.