An update of the phase III trial comparing whole pelvic to prostate only radiotherapy and neoadjuvant to adjuvant total androgen suppression: updated analysis of RTOG 94-13, with emphasis on unexpected hormone/radiation interactions

Evaluation of the current prostate cancer staging system based on cancer-specific mortality in the surveillance, epidemiology, and end results database

BACKGROUND

Prostate cancer is the most common noncutaneous malignancy diagnosed in men. From a large population-based database, this study aimed to report prostate cancer-specific mortality (PCSM) rates of men diagnosed with various presentations of prostate cancer and to examine the adequacy of the current American Joint Committee on Cancer (AJCC) staging system.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for all patients diagnosed with prostate cancer from 1997 to 2005. PCSM was reported by the classification of extent of disease provided by the SEER database, for clinically staged and pathologically staged cohorts.

RESULTS

Using the cumulative incidence method, PCSM at 10 years for all patients (n = 354,326) was 5% for clinically localized (CL) lesions, 7% for T3aN0M0, 14% for T3bN0M0, 26% for T4N0M0, 27% for TanyN1M0, and 66% for TanyNanyM1. Within the pathologically staged subgroup (n = 108,135), PCSM at 10 years was 1% for CL lesions, 4% for T3aN0M0, 9% for T3bN0M0, 9% for T4N0M0, and 19% for TanyN1M0.

CONCLUSION

Staging of any disease site aims to accurately communicate, prognosticate, and guide management for that particular level of disease. Stage IV prostate cancer is a diverse group, with PCSM in the subgroups ranging from 9% to 68% in this study. Considering the favorable outcomes of those with T4 or N1 nonmetastatic prostate cancer relative to those with M1 disease, the authors propose that T4 or N1 M0 prostate cancer should be reclassified into a new stage IIIB and that patients with such disease should be offered curative-intent therapy whenever possible.

Intensity-modulated pelvic radiation therapy and simultaneous integrated boost to the prostate area in patients with high-risk prostate cancer: a preliminary report of disease control

The aim of the study was to report the clinical results in patients with high-risk prostate cancer treated with pelvic intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost (SIB) to the prostate area. A total of 110 patients entered our study, 37 patients presented with localized prostate cancer and radiological evidence of node metastases or ≥15% estimated risk of lymph node (LN) involvement, while 73 patients underwent postoperative adjuvant or salvage irradiation for biochemical or residual/recurrent disease, LN metastases, or high risk of harboring nodal metastases. All patients received androgen deprivation therapy (ADT) for 2 years. The median follow-up was 56.5 months. For the whole patient group, the 3- and 5-year freedom from biochemical failure were 82.6% and 74.6%, respectively, with a better outcome in patients treated with radical approach. The 3- and 5-year freedom from local failure were 94.4% and 90.2%, respectively, while the 3- and 5-year distant metastasis-free survival were 87.8% and 81.7%, respectively. For all study patients, the rate of freedom from G2 acute rectal, intestinal, and urinary toxicities was 60%, 77%, and 61%, respectively. There was no G3 acute toxicity, ≥G2 late intestinal toxicity, or G3 late urinary or rectal toxicity. The 3- and 5-year ≥G2 freedom from late rectal toxicity rate were 98% and 95%, respectively, while the 3- and 5-year ≥G2 freedom from late urinary toxicity rate were 95% and 88%, respectively. The study concludes that pelvic IMRT and SIB to the prostatic area in association with 2-year ADT was a well-tolerated technique, providing high disease control in patients with prostate cancer requiring LN treatment.

Different rectal toxicity tolerance with and without simultaneous conventionally-fractionated pelvic lymph node treatment in patients receiving hypofractionated prostate radiotherapy

PURPOSE

To investigate added morbidity associated with the addition of pelvic elective nodal irradiation (ENI) to hypofractionated radiotherapy to the prostate.

METHODS AND MATERIALS

Two-hundred twelve patients, treated with hypofractionated radiotherapy to the prostate between 2004 and 2011, met the inclusion criteria for the analysis. All patients received 70 Gy to the prostate delivered over 28 fractions and 103 (49%) received ENI consisting of 50.4 Gy to the pelvic lymphatics delivered simultaneously in 1.8 Gy fractions. The mean dose-volume histograms were compared between the two subgroups defined by use of ENI, and various dose-volume parameters were analyzed for effect on late lower gastrointestinal (GI) and genitourinary (GU) toxicity.

RESULTS

Acute grade 2 lower GI toxicity occurred in 38 (37%) patients receiving ENI versus 19 (17%) in those who did not (p = 0.001). The Kaplan-Meier estimate of grade ≥ 2 lower GI toxicity at 3 years was 15.3% for patients receiving ENI versus 5.3% for those who did not (p = 0.026). Each rectal isodose volume was increased for patients receiving ENI up to 50 Gy (p ≤ 0.021 for each 5 Gy increment). Across all patients, the absolute V70 of the rectum was the only predictor of late GI toxicity. When subgroups, defined by the use of ENI, were analyzed separately, rectal V70 was only predictive of late GI toxicity for patients who received ENI. For patients receiving ENI, V70 > 3 cc was associated with an increased risk of late GI events.

CONCLUSIONS

Elective nodal irradiation increases the rates of acute and late GI toxicity when delivered simultaneously with hypofractioanted prostate radiotherapy. The use of ENI appears to sensitize the rectum to hot spots, therefore we recommend added caution to minimize the volume of rectum receiving 100% of the prescription dose in these patients.

High-dose-rate interstitial brachytherapy in combination with androgen deprivation therapy for prostate cancer: are high-risk patients good candidates?

BACKGROUND AND PURPOSE

To evaluate the effectiveness of high-dose-rate interstitial brachytherapy (HDR-ISBT) as the only form of radiotherapy for high-risk prostate cancer patients.

PATIENTS AND METHODS

Between July 2003 and June 2008, we retrospectively evaluated the outcomes of 48 high-risk patients who had undergone HDR-ISBT at the National Hospital Organization Osaka National Hospital. Risk group classification was according to the criteria described in the National Comprehensive Cancer Network (NCCN) guidelines. Median follow-up was 73 months (range 12-109 months). Neoadjuvant androgen deprivation therapy (ADT) was administered to all 48 patients; 12 patients also received adjuvant ADT. Maximal androgen blockade was performed in 37 patients. Median total treatment duration was 8 months (range 3-45 months). The planned prescribed dose was 54 Gy in 9 fractions over 5 days for the first 13 patients and 49 Gy in 7 fractions over 4 days for 34 patients. Only one patient who was over 80 years old received 38 Gy in 4 fractions over 3 days. The clinical target volume (CTV) was calculated for the prostate gland and the medial side of the seminal vesicles. A 10-mm cranial margin was added to the CTV to create the planning target volume (PTV).

RESULTS

The 5-year overall survival and biochemical control rates were 98 and 87 %, respectively. Grade 3 late genitourinary and gastrointestinal complications occurred in 2 patients (4 %) and 1 patient (2 %), respectively; grade 2 late genitourinary and gastrointestinal complications occurred in 5 patients (10 %) and 1 patient (2 %), respectively.

CONCLUSION

Even for high-risk patients, HDR-ISBT as the only form of radiotherapy combined with ADT achieved promising biochemical control results, with acceptable late genitourinary and gastrointestinal complication rates.

Clinical pharmacology and regulatory consequences of GnRH analogues in prostate cancer

INTRODUCTION

GnRH (gonadotropin-releasing hormone) analogues are long-term known to be safe and effective in the clinical management of hormone-dependent advanced prostate cancer. However, their unusual mechanism of action of de-sensitizing pituitary receptors makes generic market entry challenging. In addition, safety aspects like initial flare-up, breakthrough escape, and miniflares render planning and organization of clinical registration trials a complex project.

REGULATORY REQUIREMENTS THERAPEUTIC EQUIVALENCE

Regulatory requirements are high as these medicines are compared to bilateral surgical castration with a 100% success rate. GnRH analogues will be used probably even wider in the near future due to demographic development and extension of indications. However, they are challenged by their antagonistic counterparts, which are avoiding flare-up phenomena. The following article deals with regulatory requirements of GnRH analogues in regard to their clinical characteristics.

Current trends for the use of androgen deprivation therapy in conjunction with radiotherapy for patients with unfavorable intermediate-risk, high-risk, localized, and locally advanced prostate cancer

Androgen deprivation therapy (ADT) is now a well-established standard of care in combination with definitive radiotherapy for patients with unfavorable intermediate-risk to high-risk locally advanced prostate cancer. It is also well established that combination modality treatment with ADT and radiotherapy is superior to either of these modalities alone for the treatment of patients with high-risk locally advanced disease. Current treatment guidelines for prostate cancer in the United States are based on the estimated risk of recurrence and death. This review examines the clinical evidence underpinning the use of ADT and radiotherapy among patients with high-risk localized and locally advanced disease in the United States. This review also considers the rationale for moving from traditional luteinizing hormone-releasing hormone agonists to more recently developed gonadotrophin-releasing hormone antagonists.

Adjuvant versus salvage radiotherapy for high-risk prostate cancer patients

Radiotherapy (RT) after prostatectomy may potentially eradicate any residual localized microscopic disease in the prostate bed. The current dilemma is whether to deliver adjuvant RT solely on the basis of high-risk pathology (pT3 or positive margins), but in the absence of measurable prostate-specific antigen, or whether early salvage radiotherapy (SRT) would yield equivalent outcomes. Although the results of current randomized trials answering this very question remain years away, the best evidence to date supports early SRT as the better strategy. In terms of SRT, the pooled evidence reveals that one should initiate RT at the lowest prostate-specific antigen possible to maximize results. Similarly, the pooled data suggest that there is a dose-response favoring doses >70 Gy to the prostate bed. The evidence regarding the role of androgen deprivation therapy and the use of elective pelvic nodal RT is weak, and ongoing randomized trials are underway. Several clinical scenarios are presented for discussion.

[Radiation therapy in locally advanced and/or relapsed urological tumors]

Radiation therapy (RT) plays a fundamental role in the treatment of locally advanced and/or relapsed urological tumors, as well as in palliation, or as definitive treatment, and even where integrated into a multi-modal approach. In operated renal tumors, positive margins or extracapsular extension show a positive impact of postoperative RT, with a reduction of relapses between 100% and 30%, while, in the case of palliation, treatments with RT at high doses are preferred. In advanced cancers of the upper urinary tract, RT plays a limited role, even if it seems to increase the level of disease control locally and, with the combination of cisplatin, survival rates too. An important reduction in the recurrence is also observed in locally advanced tumors of the urethra, with a recurrence of 60% after surgery, 36% after RT and 25% after pairing of the two. In locally advanced tumors of the penis, RT shows poorer results than surgery, and the addition of postoperative RT does not seem to add any further outcome, except where, in the presence of a positive inguinal dissection, the postoperative RT reduces lymph node recurrences by 60%-11%. Interesting data for the preservation of the organ are reported with reference to the combination with chemotherapy. In the tumors of the testis, it is still disputable whether the treatment of residual masses after chemotherapy may be appropriate, with a view to a possible salvage radiotherapy. In the treatment of the prostate, the role of RT is consolidated and evolving with the progress of dose escalation, the association with hormonal therapy, new technologies, new possibilities of IMRT and proton therapy and various studies on multi-modal approaches (hormone therapy, surgery, radiotherapy, chemotherapy). Cystectomy is the gold standard for the treatment of locally advanced bladder cancer, even though there is a revived interest in multimodal treatments (transurethral resection, chemotherapy, RT) that may allow the organ preservation. Postoperative radiotherapy, which can reduce by 50% to 20%-5% local recurrences that are highly correlated with distance failure and with survival, should be revised in the light of modern RT techniques that can further increase local control levels and reduce the toxicity significantly.

Whole pelvic intensity-modulated radiotherapy for high-risk prostate cancer: a preliminary report

Purpose

To assess the clinical efficacy and toxicity of whole pelvic intensity-modulated radiotherapy (WP-IMRT) for high-risk prostate cancer.

Materials and Methods

Patients with high-risk prostate cancer treated between 2008 and 2013 were reviewed. The study included patients who had undergone WP-IMRT with image guidance using electronic portal imaging devices and/or cone-beam computed tomography. The endorectal balloon was used in 93% of patients. Patients received either 46 Gy to the whole pelvis plus a boost of up to 76 Gy to the prostate in 2 Gy daily fractions, or 44 Gy to the whole pelvis plus a boost of up to 72.6 Gy to the prostate in 2.2 Gy fractions.

Results

The study cohort included 70 patients, of whom 55 (78%) had a Gleason score of 8 to 10 and 50 (71%) had a prostate-specific antigen level > 20 ng/mL. The androgen deprivation therapy was combined in 62 patients. The biochemical failure-free survival rate was 86.7% at 2 years. Acute any grade gastrointestinal (GI) and genitourinary (GU) toxicity rates were 47% and 73%, respectively. The actuarial rate of late grade 2 or worse toxicity at 2 years was 12.9% for GI, and 5.7% for GU with no late grade 4 toxicity.

Conclusion

WP-IMRT was well tolerated with no severe acute or late toxicities, resulting in at least similar biochemical control to that of the historic control group with a small field. The long-term efficacy and toxicity will be assessed in the future, and a prospective randomized trial is needed to verify these findings.

FROGG high-risk prostate cancer workshop: patterns of practice and literature review: part I: intact prostate

Australian and New Zealand radiation oncologists with an interest in uro-oncology were invited to participate in a pattern-of-practice survey dealing with the management of intact high-risk prostate cancer. Responses from 46 practitioners (representing 73% of all potential respondents) revealed that high-dose radiation therapy is the standard of care. However, there is variability in practice with regard to the methods used to achieve dose escalation, the use of whole-pelvic radiation therapy and the optimal duration of androgen deprivation therapy employed. A review of the literature outlining the current body of knowledge and the planned and ongoing studies in intact high-risk prostate cancer is presented.

β1 integrins mediate resistance to ionizing radiation in vivo by inhibiting c-Jun amino terminal kinase 1

This study was carried out to dissect the mechanism by which β1 integrins promote resistance to radiation. For this purpose, we conditionally ablated β1 integrins in the prostatic epithelium of transgenic adenocarcinoma of mouse prostate (TRAMP) mice. The ability of β1 to promote resistance to radiation was also analyzed by using an inhibitory antibody to β1 , AIIB2, in a xenograft model. The role of β1 integrins and of a β1 downstream target, c-Jun amino-terminal kinase 1 (JNK1), in regulating radiation-induced apoptosis in vivo and in vitro was studied. We show that β1 integrins promote prostate cancer (PrCa) progression and resistance to radiation in vivo. Mechanistically, β1 integrins are shown here to suppress activation of JNK1 and, consequently apoptosis, in response to irradiation. Downregulation of JNK1 is necessary to preserve the effect of β1 on resistance to radiation in vitro and in vivo. Finally, given the established crosstalk between β1 integrins and type1 insulin-like growth factor receptor (IGF-IR), we analyzed the ability of IGF-IR to modulate β1 integrin levels. We report that IGF-IR regulates the expression of β1 integrins, which in turn confer resistance to radiation in PrCa cells. In conclusion, this study demonstrates that β1 integrins mediate resistance to ionizing radiation through inhibition of JNK1 activation.

Contemporary issues in radiotherapy for clinically localized prostate cancer

Radiotherapy is a valid curative alternative to surgery for prostate cancer. However, patient selection is critical to ensure patients obtain benefits from therapy delivered with curative intent. Dose-escalated radiation has been shown to improve patient outcomes, facilitated by development of robust image guidance and better target delineation imaging technologies. These concepts have also rekindled interest in hypofractionated radiotherapy in the forms of stereotactic body radiotherapy and brachytherapy. Postprostatectomy radiotherapy also improves long-term biochemical outcome in men at high risk of local recurrence.

EAU guidelines on prostate cancer. part 1: screening, diagnosis, and local treatment with curative intent-update 2013

CONTEXT

The most recent summary of the European Association of Urology (EAU) guidelines on prostate cancer (PCa) was published in 2011.

OBJECTIVE

To present a summary of the 2013 version of the EAU guidelines on screening, diagnosis, and local treatment with curative intent of clinically organ-confined PCa.

EVIDENCE ACQUISITION

A literature review of the new data emerging from 2011 to 2013 has been performed by the EAU PCa guideline group. The guidelines have been updated, and levels of evidence and grades of recommendation have been added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews.

EVIDENCE SYNTHESIS

A full version of the guidelines is available at the EAU office or online (www.uroweb.org). Current evidence is insufficient to warrant widespread population-based screening by prostate-specific antigen (PSA) for PCa. Systematic prostate biopsies under ultrasound guidance and local anesthesia are the preferred diagnostic method. Active surveillance represents a viable option in men with low-risk PCa and a long life expectancy. A biopsy progression indicates the need for active intervention, whereas the role of PSA doubling time is controversial. In men with locally advanced PCa for whom local therapy is not mandatory, watchful waiting (WW) is a treatment alternative to androgen-deprivation therapy (ADT), with equivalent oncologic efficacy. Active treatment is recommended mostly for patients with localized disease and a long life expectancy, with radical prostatectomy (RP) shown to be superior to WW in prospective randomized trials. Nerve-sparing RP is the approach of choice in organ-confined disease, while neoadjuvant ADT provides no improvement in outcome variables. Radiation therapy should be performed with ≥ 74 Gy in low-risk PCa and 78 Gy in intermediate- or high-risk PCa. For locally advanced disease, adjuvant ADT for 3 yr results in superior rates for disease-specific and overall survival and is the treatment of choice. Follow-up after local therapy is largely based on PSA and a disease-specific history, with imaging indicated only when symptoms occur.

CONCLUSIONS

Knowledge in the field of PCa is rapidly changing. These EAU guidelines on PCa summarize the most recent findings and put them into clinical practice.

PATIENT SUMMARY

A summary is presented of the 2013 EAU guidelines on screening, diagnosis, and local treatment with curative intent of clinically organ-confined prostate cancer (PCa). Screening continues to be done on an individual basis, in consultation with a physician. Diagnosis is by prostate biopsy. Active surveillance is an option in low-risk PCa and watchful waiting is an alternative to androgen-deprivation therapy in locally advanced PCa not requiring immediate local treatment. Radical prostatectomy is the only surgical option. Radiation therapy can be external or delivered by way of prostate implants. Treatment follow-up is based on the PSA level.

Lessons learned from radiation oncology clinical trials

A workshop entitled "Lessons Learned from Radiation Oncology Trials" was held on December 7-8, 2011, in Bethesda, MD, to present and discuss some of the recently conducted radiation oncology clinical trials with a focus on those that failed to refute the null hypothesis. The objectives of this workshop were to summarize and examine the questions that these trials provoked, to assess the quality and limitations of the preclinical data that supported the hypotheses underlying these trials, and to consider possible solutions to these challenges for the design of future clinical trials. Several themes emerged from the discussions: (i) opportunities to learn from null-hypothesis trials through tissue and imaging studies; (ii) value of preclinical data supporting the design of combinatorial therapies; (iii) significance of validated biomarkers; (iv) necessity of quality assurance in radiotherapy delivery; (v) conduct of sufficiently powered studies to address the central hypotheses; and (vi) importance of publishing results of the trials regardless of the outcome. The fact that well-designed hypothesis-driven clinical trials produce null or negative results is expected given the limitations of trial design and complexities of cancer biology. It is important to understand the reasons underlying such null results, however, to effectively merge the technologic innovations with the rapidly evolving biology for maximal patient benefit through the design of future clinical trials.

The emerging role of high-dose-rate (HDR) brachytherapy as monotherapy for prostate cancer

High-dose-rate (HDR) brachytherapy as monotherapy is a comparatively new brachytherapy procedure for prostate cancer. In addition to the intrinsic advantages of brachytherapy, including radiation dose concentration to the tumor and rapid dose fall-off at the surrounding normal tissue, HDR brachytherapy can yield a more homogeneous and conformal dose distribution through image-based decisions for source dwell positions and by optimization of individual source dwell times. Indication can be extended even to T3a/b or a part of T4 tumors because the applicators can be positioned at the extracapsular lesion, into the seminal vesicles, and/or into the bladder, without any risk of source migration or dropping out. Unlike external beam radiotherapy, with HDR brachytherapy inter-/intra-fraction organ motion is not problematic. However, HDR monotherapy requires patients to stay in bed for 1-4 days during hospitalization, even though the actual overall treatment time is short. Recent findings that the α/β value for prostate cancer is less than that for the surrounding late-responding normal tissue has made hypofractionation attractive, and HDR monotherapy can maximize this advantage of hypofractionation. Research on HDR monotherapy is accelerating, with a growing number of publications reporting excellent preliminary clinical results due to the high 'biologically effective dose (BED)' of >200 Gy. Moreover, the findings obtained for HDR monotherapy as an early model of extreme hypofractionation tend to be applied to other radiotherapy techniques such as stereotactic radiotherapy. All these developments point to the emerging role of HDR brachytherapy as monotherapy for prostate cancer.

[Pelvic irradiation in prostate cancer: what place for what volumes?]

External beam radiotherapy alone is a standard treatment for prostate cancer. According to clinical, histological and biological characteristics of the tumour, lymph node irradiation can be done in combination with irradiation of the prostate. The completion of pelvic irradiation remains controversial and may cause complications by increasing volumes of irradiated healthy tissues. The accuracy of the delineation of lymph node becomes an important issue. This article proposes to take on the characteristics of the pelvic lymph node drainage of the prostate, to review the literature on pelvic irradiation and the definition of volumes to be irradiated.

Agonists of luteinizing hormone-releasing hormone in prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) has been the first-line standard of care for treating patients with hormone-sensitive advanced prostate cancer (PCa) for many decades. The agonists of luteinizing hormone-releasing hormone (LHRH), also called gonadotropin-releasing hormone, are still the most frequently used form of medical ADT.

AREAS COVERED

This article reviews the available data and most recent information concerning the use of LHRH agonists in advanced PCa. This article also reviews the discovery and development of LHRH agonists and summarizes the clinical evidence for their efficacy in PCa.

EXPERT OPINION

The introduction and application of agonists of LHRH has modernized and improved the treatment of advanced PCa. The life-saving benefits of LHRH agonists are well established, yet underestimated. Despite their efficacy, agonists of LHRH have several disadvantages or drawbacks including disease flare. The approach to ADT has been recently further refined with the development of the LHRH antagonist degarelix. Degarelix, a highly clinically effective third-generation LHRH antagonist, is currently available in most countries for therapy of advanced PCa. This new drug offers attractive alternatives to LHRH agonists for treatment of advanced PCa. A therapy for castration-resistant PCa based on a targeted cytotoxic analog of LHRH, AEZS-108, is also emerging.

Efficacy and toxicity of conventionally fractionated pelvic radiation with a hypofractionated simultaneous versus conventionally fractionated sequential boost for patients with high-risk prostate cancer

PURPOSE

To determine if high-risk prostate cancer responds differently to hypofractionation.

MATERIAL AND METHODS

One hundred and fifty-seven men with NCCN high-risk (T3, PSA > 20, or Gleason ≥ 8) clinically localized prostate cancer treated between 1998 and 2010 met the inclusion criteria for the analysis. Eighty-two were treated with conventional WPRT with a conventionally fractionated sequential boost to the prostate (cRT), with the prostate receiving 75-77 Gy in 1.8-2.0 Gy fractions. Seventy-five were treated with pelvic IMRT with a hypofractionated simultaneous boost to the prostate (hRT), with the prostate receiving 70 Gy in 2.5 Gy fractions. The dose to the pelvic lymph nodes was 45 Gy in the cRT group and 50.4 Gy in the hRT group, both at 1.8 Gy per fraction. Ninety-two percent received neoadjuvant hormonal ablation therapy, typically beginning two months prior to the start of RT.

RESULTS

Median follow-up was 6.5 years for men receiving cRT and 3.7 years for those receiving hRT. The actuarial rate of biochemical control at four years was 88% for cRT and 94% for hRT (p = 0.82). The rates of early rectal and urinary grade ≥ 2 toxicities were 35% (29 of 82) and 49% (40 of 82) for the cRT group and 36% (27 of 75) and 44% (33 of 75) for the hRT group. The actuarial rate of late grade ≥ 2 rectal toxicity at four years was 25% for the cRT group and 13% for the hRT group (p = 0.037). The rate of late grade 3 rectal complications was 4% (3 of 82) for patients receiving cRT and 1% (1 of 75) for patients receiving hRT.

CONCLUSION

Initial follow-up indicates equivalent biochemical control between regimens. Patients receiving hRT experienced fewer late rectal complications.

A retrospective analysis of the prognosis of prostate cancer patients with lymph node involvement on MR lymphography: who might be cured

Background

The prognosis of prostate cancer patients with lymph node metastases so small they can only be visualized by new imaging techniques as MR lymphography (MRL) is unknown. The purpose of this study was to investigate the prognosis of prostate cancer patients with non-enlarged metastatic lymph nodes on MRL and to identify a subgroup of MRL-positive patients who might be candidates for curative treatment.

Methods

The charts of 138 prostate cancer patients without enlarged lymph nodes on CT, in whom a pre-treatment MRL was performed were reviewed. Endpoints were distant metastases-free survival and overall survival. Relation between the following factors and outcome were investigated: T-stage, PSA value at diagnosis, Gleason score, diameter (short axis and long axis) of the largest MRL-positive lymph node, number of MRL-positive lymph nodes, the presence of extra-pelvic nodal disease, and the extent of resection of the positive lymph nodes. Kaplan-Meier analysis was performed to estimate the survival functions.

Results

Of the 138 patients, 24 (17%) had a positive MRL. Patients with a short axis of the largest positive lymph node of ≤8 mm had a significantly better 5-year distant metastases-free (79% vs 16%) and overall survival (81% vs 36%) than patients with larger positive lymph nodes. This also accounted for patients with a largest long axis of ≤10 mm (71% vs 20% and 73% vs 40%, respectively). Outcome was also better in patients in whom all positive lymph nodes had been resected.

Conclusion

A selection of MRL-positive patients with a good prognosis could be identified, consisting of patients with small positive lymph nodes. In these patients, cure might be pursued.

Comparison study of intensity modulated arc therapy using single or multiple arcs to intensity modulated radiation therapy for high-risk prostate cancer

Purpose

Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer.

Materials and Methods

Sixteen patients were studied. Prostate (PTV_P), right pelvic (PTV_RtLN) and left pelvic lymph nodes (PTV_LtLN), and organs at risk were contoured. PTV_P, PTV_RtLN, and PTV_LtLN received 50.40 Gy followed by a boost to PTV_B of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D_MEAN) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated.

Results

Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The D_MEAN of bladder was within 2% of each other. The rectum D_MEAN in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05).

Conclusion

For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

Radical radiotherapy in high-risk prostate cancer patients with high or ultra-high initial PSA levels: a single institution analysis

PURPOSE

Purpose of this study is to analyze outcomes and pre-treatment prognostic factors in high-risk prostate cancer patients with initial PSA ≥ 20 ng/mL, treated with high-dose external beam radiotherapy (EBRT) and androgen deprivation therapy (ADT) in a single institution.

METHODS

Between March 2003 and December 2011, 155 consecutive high-risk prostate cancer patients (a) presenting with pre-treatment PSA level ≥ 20 ng/mL, (b) treated with definitive EBRT, and (c) with a minimum follow-up of 24 months were included in this retrospective analysis. Phoenix definition was used to define biochemical control. Primary endpoints were as follows: biochemical disease-free survival (bDFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS) and overall survival (OS). Multivariate analysis was performed to determine the independent prognostic impact of pre-treatment clinical factors [T stage, PSA, and Gleason score (GS)].

RESULTS

At a median follow-up time of 62 months, actuarial bDFS, DMFS, CSS, and OS at 5 years were 64.8, 85.2, 95.8, and 94.4 %, respectively. On multivariate analysis, only GS was significantly associated with three clinical endpoints (bDFS: HR 1.6; p = 0.022, CSS: HR 4.27, p = 0.044, OS: HR 2.6; p = 0.038). Pre-treatment zenith PSA was associated only with bDFS (HR 1.87; p = 0.027).

CONCLUSIONS

Patients with "high" PSA levels (≥ 20 ng/mL) showed favorable clinical outcomes, supporting the role of local radiotherapy as primary therapy in combination with long-term ADT in patients with high PSA levels at diagnosis. A GS of 8-10 is the strongest predictor of outcome.

Current standards and future directions for prostate cancer radiation therapy

Definitive radiation therapy is a well-recognized curative treatment option for localized prostate cancer. A suitable technique, dose, target volume and the option of a combination with androgen deprivation therapy need to be considered. An optimal standard external beam radiotherapy currently includes intensity-modulated and image-guided radiotherapy techniques with total doses of ≥76-78 Gy in conventional fractionation. Protons or carbon ions are alternatives available only in specific centers. Data from several randomized studies increasingly support the rationale for hypofractionated radiotherapy. A simultaneous integrated boost with dose escalation focused on a computed tomography/PET- or MRI/magnetic resonance spectroscopy-detected malignant lesion is one option to increase tumor control, with potentially no additional toxicity. The application of a spacer is a promising concept for optimal protection of the rectal wall.

Individualized image-based lymph node irradiation for prostate cancer

Controversy surrounds the benefit of whole pelvis radiotherapy (WPRT) over prostate-only radiotherapy (PORT) for intermediate-risk and high-risk patients with prostate cancer. In the PSA screening era, two large randomized trials as well as multiple retrospective studies comparing WPRT with PORT have been performed, albeit with contradictory results. Data regarding the use of WPRT in patients with biochemical recurrence after prostatectomy are scarce. As a consequence, the practice of WPRT varies worldwide. Advanced highly accurate imaging methods for the detection of lymph node metastases in patients with prostate cancer have been developed, such as PET, single photon emission computed tomography (SPECT), diffusion-weighted MRI and magnetic resonance lymphography (MRL). The use of these new imaging methods might improve nodal irradiation, as they can be used not only for selection of patients, but also for accurately determining the target volume to reduce geographical miss. Furthermore, these new techniques can enable dose escalation to involved lymph nodes.

Radiotherapy with rectangular fields is associated with fewer clinical failures than conformal fields in the high-risk prostate cancer subgroup: results from a randomized trial

OBJECTIVE

High-risk prostate cancer patients are at risk for subclinical disease and micro-metastasis at the time of treatment. Nowadays, tight margins reduce dose to periprostatic areas compared to earlier techniques. We investigated whether rectangular fields were associated with fewer failures compared to conformal fields (with lower extraprostatic dose).

METHODS

We selected 164 high-risk patients from the trial population of 266 T1-T4N0M0 patients, randomized between rectangular (n=79) and conformal fields (n=85). Prescribed dose was 66 Gy to the prostate and seminal vesicles plus 15 mm margin. We compared clinical failure rates (in- and excluding local failures), between both arms. Dose differences around the prostate were calculated based on an inter-patient mapping method.

RESULTS

Median follow-up was 34 months. There were 9 clinical failures in the rectangular arm versus 24 in the conformal arm (p=0.012). Number of failures outside the prostate was 7 and 19, respectively (p=0.025). We observed average dose differences of 5-35 Gy between the arms in the regions around the prostate.

CONCLUSIONS

We found a significantly lower risk of early tumor progression for patients treated with rectangular fields. Treatment failure can probably in part be prevented by irradiation of areas suspected of subclinical disease in high-risk prostate cancer.

Optimal planning target volume margins for elective pelvic lymphatic radiotherapy in high-risk prostate cancer patients

Purpose. High-risk prostate cancer patients often receive radiotherapy (RT) to pelvic lymphatics (PLs). The aim of this study was to determine the safety margin around clinical target volume for PL (PL-CTV) to construct planning target volume for PL (PL-PTV) and for planning elective PL irradiation. Methods and Materials. Six patients who received RT to PL as part of prostate cancer treatment were identified. To determine average daily shifts of PL, the right and left IVs were contoured at 3 predetermined slices on the daily MV scans and their daily shifts were measured at these 3 levels using a measuring tool. Results. A total of 1,932 observations were made. Daily shifts of IV were random in distribution, and the largest observed shift was 13.6 mm in lateral and 15.4 mm in AP directions. The mean lateral and AP shifts of IV were 2.1 mm (±2.2) and 3.5 mm (±2.7), respectively. The data suggest that AP and lateral margins of 8.9 mm and 6.5 mm are necessary. Conclusions. With daily alignment to the prostate, we recommend an additional PL-CTV to PL-PTV conversion margin of 9 mm (AP) and 7 mm (lateral) to account for daily displacement of PL relative to the prostate.

Computer-assisted, atlas-based segmentation for target volume delineation in whole pelvic IMRT for prostate cancer

The purpose of this study is to evaluate whether computer-assisted segmentation is clinically feasible in target volume delineation for prostate cancer patients treated with whole pelvic IMRT. An atlas was created, comprised of 44 clinically node-negative prostate cancer patients. Three regions of interest (ROIs) were chosen for analysis: prostate, pelvic lymph nodes, and rectum. For a separate tester set of 15 patients with previously contoured ROIs by three experienced physicians, atlas-assisted contours were compared to manual contours by calculating a volumetric overlap index. In the tester set patients, the average overlap between the manually drawn and atlas-based contours for the prostate, pelvic lymph nodes, and rectum was 60%, 51%, and 64%, respectively. The volume differences were significant in the rectum and pelvic lymph nodes (p = 0.049 and p = 0.016, respectively); this was not true for the prostate. A subset analysis based on physician-specific atlases showed that the average overlap index for the pelvic lymph nodal volume increased from 51% to 60%, while the other ROIs had no significant changes. Despite significant inter-physician differences, atlas-based segmentation for pelvic lymph node delineation serves as an initial guideline for physicians, potentially improving both consistency and efficiency in contouring.

[Radiotherapy with androgen deprivation in high-risk prostate cancer: what outcomes on a Caribbean population?]

OBJECTIVE

To analyze in a Caribbean population at 90% of African descent, the results of radiotherapy with androgen deprivation (AD) in high-risk prostate cancer (PCa).

PATIENTS AND METHODS

Fifty-nine consecutive patients with a high-risk PCa as defined by the D'AMICO classification and treated by radiotherapy with AD between January 2003 and April 2009 in our center were analyzed. The median dose of radiation and the median duration of AD were 70Gy and 37months respectively. Biochemical recurrence (BF), as primary outcome was defined according to the PHOENIX criteria (nadir PSA+2ng/mL). Multivariate analysis was performed to identify predictive factors of BF. The median follow-up was 47months.

RESULTS

Eight (13.6%) patients had BF and four (6.8%) developed metastases. Six (10.2%) died during the follow-up. The 5years acturial biochemical disease-free survival was 79.7%. Multivariate analyses have shown that Gleason sum (GS) superior to 7 (P=0.029), AD duration less than 24months (P=0.004) and the rate of Nadir PSA greater or equal to 0.5ng/mL (P=0.011) were independent predictive factors of BF.

CONCLUSION

This study was the first to our knowledge, to provide that radiotherapy associate with AD for HRPC among Caribbean men is effective as observed in other populations. Patients with GS superior to 7 could be considered for more aggressive treatments in clinical trials.

Tissue biomarkers for prostate cancer radiation therapy

Prostate cancer is the most common cancer and second leading cause of cancer deaths among men in the United States. Most men have localized disease diagnosed following an elevated serum prostate specific antigen test for cancer screening purposes. Standard treatment options consist of surgery or definitive radiation therapy directed by clinical factors that are organized into risk stratification groups. Current clinical risk stratification systems are still insufficient to differentiate lethal from indolent disease. Similarly, a subset of men in poor risk groups need to be identified for more aggressive treatment and enrollment into clinical trials. Furthermore, these clinical tools are very limited in revealing information about the biologic pathways driving these different disease phenotypes and do not offer insights for novel treatments which are needed in men with poor-risk disease. We believe molecular biomarkers may serve to bridge these inadequacies of traditional clinical factors opening the door for personalized treatment approaches that would allow tailoring of treatment options to maximize therapeutic outcome. We review the current state of prognostic and predictive tissue-based molecular biomarkers which can be used to direct localized prostate cancer treatment decisions, specifically those implicated with definitive and salvage radiation therapy.

The current role of androgen deprivation in patients undergoing dose-escalated external beam radiation therapy for clinically localized prostate cancer

Purpose. To review existing literature on the role of androgen deprivation therapy (ADT) with dose escalated radiation therapy. Methods and Materials. A PubMed search was undertaken to identify relevant articles. Results. Multiple recent studies were identified examining the role of ADT in the current era of radiation dose-escalation. Among the reviewed studies, varying radiation doses and techniques, ADT regimens, and patient selection criteria were utilized. Conflicting results were reported, with some studies demonstrating a benefit of delivering a higher radiation dose with ADT. Other studies failed to show significant benefits with the addition of ADT to dose-escalated RT. Conclusions. The benefit of adding ADT to dose-escalated RT is still uncertain. Prospective randomized trials, several of which are ongoing, are necessary to more adequately examine this issue. In the interim, physicians and patients should continue to utilize the existing data to weigh the risks and benefits of each approach to therapy.

Androgen deprivation therapy in combination with radiotherapy for high-risk clinically localized prostate cancer

Androgen deprivation therapy (ADT) has remained the main therapeutic option for patients with advanced prostate cancer (PCa) for about 70 years. Several reports and our findings revealed that aggressive PCa can occur under a low dihydrotestosterone (DHT) level environment where the PCa of a low malignancy with high DHT dependency cannot easily occur. Low DHT levels in the prostate with aggressive PCa are probably sufficient to propagate the growth of the tumor, and the prostate with aggressive PCa can produce androgens from the adrenal precursors more autonomously than that with non-aggressive PCa does under the low testosterone environment with testicular suppression. In patients treated with ADT the pituitary-adrenal axis mediated by adrenocorticotropic hormone has a central role in the regulation of androgen synthesis. Several experimental studies have confirmed the potential benefits from the combination of ADT with radiotherapy (RT). A combination of external RT with short-term ADT is recommended based on the results of phase III randomized trials. In contrast, the combination of RT plus 6 months of ADT provides inferior survival as compared with RT plus 3 years of ADT in the treatment of locally advanced PCa. Notably, randomized trials included patients with diverse risk groups treated with older RT modalities, a variety of ADT scheduling and duration and, importantly, suboptimal RT doses. The use of ADT with higher doses of RT or newer RT modalities has to be properly assessed.

Comparative effectiveness research for prostate cancer radiation therapy: current status and future directions

Comparative effectiveness research aims to help clinicians, patients and policymakers make informed treatment decisions under real-world conditions. Prostate cancer patients have multiple treatment options, including active surveillance, androgen deprivation therapy, surgery and multiple modalities of radiation therapy. Technological innovations in radiation therapy for prostate cancer have been rapidly adopted into clinical practice despite relatively limited evidence for effectiveness showing the benefit for one modality over another. Comparative effectiveness research has become an essential component of prostate cancer research to help define the benefits, risks and effectiveness of the different radiation therapy modalities currently in use for prostate cancer treatment.

HDR Brachytherapy in the Management of High-Risk Prostate Cancer

High-dose-rate (HDR) brachytherapy is used with increasing frequency for the treatment of prostate cancer. It is a technique which allows delivery of large individual fractions to the prostate without exposing adjacent normal tissues to unacceptable toxicity. This approach is particularly favourable in prostate cancer where tumours are highly sensitive to dose escalation and to increases in radiotherapy fraction size, due to the unique radiobiological behaviour of prostate cancers in contrast with other malignancies. In this paper we discuss the rationale and the increasing body of clinical evidence for the use of this technique in patients with high-risk prostate cancer, where it is combined with external beam radiotherapy. We highlight practical aspects of delivering treatment and discuss toxicity and limitations, with particular reference to current practice in the United Kingdom.