Hypofractionated SBRT versus conventionally fractionated EBRT for prostate cancer: comparison of PSA slope and nadir

Background

Patients with early stage prostate cancer have a variety of curative radiotherapy options, including conventionally-fractionated external beam radiotherapy (CF-EBRT) and hypofractionated stereotactic body radiotherapy (SBRT). Although results of CF-EBRT are well known, the use of SBRT for prostate cancer is a more recent development, and long-term follow-up is not yet available. However, rapid post-treatment PSA decline and low PSA nadir have been linked to improved clinical outcomes. The purpose of this study was to compare the PSA kinetics between CF-EBRT and SBRT in newly diagnosed localized prostate cancer.

Materials/methods

75 patients with low to low-intermediate risk prostate cancer (T1-T2; GS 3 + 3, PSA < 20 or 3 + 4, PSA < 15) treated without hormones with CF-EBRT (>70.2 Gy, <76 Gy) to the prostate only, were identified from a prospectively collected cohort of patients treated at the University of California, San Francisco (1997–2012). Patients were excluded if they failed therapy by the Phoenix definition or had less than 1 year of follow-up or <3 PSAs. 43 patients who were treated with SBRT to the prostate to 38 Gy in 4 daily fractions also met the same criteria. PSA nadir and rate of change in PSA over time (slope) were calculated from the completion of RT to 1, 2 and 3 years post-RT.

Results

The median PSA nadir and slope for CF-EBRT was 1.00, 0.72 and 0.60 ng/ml and -0.09, -0.04, -0.02 ng/ml/month, respectively, for durations of 1, 2 and 3 years post RT. Similarly, for SBRT, the median PSA nadirs and slopes were 0.70, 0.40, 0.24 ng and -0.09, -0.06, -0.05 ng/ml/month, respectively. The PSA slope for SBRT was greater than CF-EBRT (p < 0.05) at 2 and 3 years following RT, although similar during the first year. Similarly, PSA nadir was significantly lower for SBRT when compared to EBRT for years 2 and 3 (p < 0.005).

Conclusion

Patients treated with SBRT experienced a lower PSA nadir and greater rate of decline in PSA 2 and 3 years following completion of RT than with CF-EBRT, consistent with delivery of a higher bioequivalent dose. Although follow-up for SBRT is limited, the improved PSA kinetics over CF-EBRT are promising for improved biochemical control.

Outcomes after post-operative radiation therapy

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Background: Adjuvant radiotherapy following radical prostatectomy has been shown to improve prostate-specific antigen (PSA) recurrence free survival for patients with high-risk pathologic features. However, an alternative strategy is careful follow-up after surgery and selective salvage radiation therapy. We aim to investigate voiding and sexual function, and oncological outcomes of patients who underwent adjuvant radiotherapy (ARD) or salvage radiotherapy (SRT) after radical prostatectomy (RP). Methods: We conducted a retrospective analysis of patients with localized prostate cancer treated with open or robotic assisted laparoscopic RP at the University of California, San Francisco (UCSF) from 2002 to 2013. Primary outcomes were voiding and sexual function, PSA recurrence-free survival (PRFS), combined bone metastasis free-survival/cancer-specific survival (BMFS/CSS), and overall survival (OS). Survival outcomes were analyzed using the Kaplan-Meier method. Results: Among 2,908 men in the study, mean age was 60, median PSA was 5.9 ng/ml, and median PSA density was 0.19 at diagnosis. Median follow-up was 28 months (IQR 8-61). Of those with high risk pathologic features, 1,086 patients did not undergo post-RP radiation (NRT), 109 had ART, and 156 had SRT. All patients had comparable pre-treatment sexual and voiding function. However, patients treated with ART or SRT had worse sexual function (SHIM scores) at 4 years post-RP compared to patients without radiation (5.2 (ART/SRT) versus 11.1 (NRT), p=0.01). There were no differences in voiding function at 4 years between the three groups. PRFS at 4 years was 92% for NRT, 82% for ART, and 55% for SRT cohort, log-rank p<0.01. Four-year BMFS/CSS and OS both were 98% and were similar for all groups. In a sub-analysis of men with stage pT2/3a, positive margins, and negative lymph nodes, PRFS were 86% (NRT) and 90% (ART). The PRFS following SRT was 63%. Conclusions: This study provides novel information on both oncological and functional outcomes for men managed with surgery and post-operative radiation therapy at UCSF. Such information allows for better pre- and post-operative counseling of men. Further analyses are required to better determine which men benefit from immediate adjuvant radiation as compared to a strategy of surveillance followed by selective salvage radiation.

Cold spot mapping inferred from MRI at time of failure predicts biopsy-proven local failure after permanent seed brachytherapy in prostate cancer patients: implications for focal salvage brachytherapy

BACKGROUND AND PURPOSE

(1) To establish a method to evaluate dosimetry at the time of primary prostate permanent implant (pPPI) using MRI of the shrunken prostate at the time of failure (tf). (2) To compare cold spot mapping with sextant-biopsy mapping at tf.

MATERIAL AND METHODS

Twenty-four patients were referred for biopsy-proven local failure (LF) after pPPI. Multiparametric MRI and combined-sextant biopsy with a central review of the pathology at tf were systematically performed. A model of the shrinking pattern was defined as a Volumetric Change Factor (VCF) as a function of time from time of pPPI (t0). An isotropic expansion to both prostate volume (PV) and seed position (SP) coordinates determined at tf was performed using a validated algorithm using the VCF.

RESULTS

pPPI CT-based evaluation (at 4weeks) vs. MR-based evaluation: Mean D90% was 145.23±19.16Gy [100.0-167.5] vs. 85.28±27.36Gy [39-139] (p=0.001), respectively. Mean V100% was 91.6±7.9% [70-100%] vs. 73.1±13.8% [55-98%] (p=0.0006), respectively. Seventy-seven per cent of the pathologically positive sextants were classified as cold.

CONCLUSIONS

Patients with biopsy-proven LF had poorer implantation quality when evaluated by MRI several years after implantation. There is a strong relationship between microscopic involvement at tf and cold spots.

Adjuvant and salvage radiation therapy after prostatectomy: American Society for Radiation Oncology/American Urological Association guidelines

PURPOSE

The purpose of this guideline was to provide a clinical framework for the use of radiation therapy after radical prostatectomy as adjuvant or salvage therapy.

METHODS AND MATERIALS

A systematic literature review using PubMed, Embase, and Cochrane database was conducted to identify peer-reviewed publications relevant to the use of radiation therapy after prostatectomy. The review yielded 294 articles; these publications were used to create the evidence-based guideline statements. Additional guidance is provided as Clinical Principles when insufficient evidence existed.

RESULTS

Guideline statements are provided for patient counseling, use of radiation therapy in the adjuvant and salvage contexts, defining biochemical recurrence, and conducting a restaging evaluation.

CONCLUSIONS

Physicians should offer adjuvant radiation therapy to patients with adverse pathologic findings at prostatectomy (ie, seminal vesicle invastion, positive surgical margins, extraprostatic extension) and salvage radiation therapy to patients with prostate-specific antigen (PSA) or local recurrence after prostatectomy in whom there is no evidence of distant metastatic disease. The offer of radiation therapy should be made in the context of a thoughtful discussion of possible short- and long-term side effects of radiation therapy as well as the potential benefits of preventing recurrence. The decision to administer radiation therapy should be made by the patient and the multidisciplinary treatment team with full consideration of the patient's history, values, preferences, quality of life, and functional status. The American Society for Radiation Oncology and American Urological Association websites show this guideline in its entirety, including the full literature review.

Improving plan quality and consistency by standardization of dose constraints in prostate cancer patients treated with CyberKnife

Treatment plans for prostate cancer patients undergoing stereotactic body radiation therapy (SBRT) are often challenging due to the proximity of organs at risk. Today, there are no objective criteria to determine whether an optimal treatment plan has been achieved, and physicians rely on their personal experience to evaluate the plan's quality. In this study, we propose a method for determining rectal and bladder dose constraints achievable for a given patient's anatomy. We expect that this method will improve the overall plan quality and consistency, and facilitate comparison of clinical outcomes across different institutions. The 3D proximity of the organs at risk to the target is quantified by means of the expansion-intersection volume (EIV), which is defined as the intersection volume between the target and the organ at risk expanded by 5 mm. We determine a relationship between EIV and relevant dosimetric parameters, such as the volume of bladder and rectum receiving 75% of the prescription dose (V75%). This relationship can be used to establish institution-specific criteria to guide the treatment planning and evaluation process. A database of 25 prostate patients treated with CyberKnife SBRT is used to validate this approach. There is a linear correlation between EIV and V75% of bladder and rectum, confirming that the dose delivered to rectum and bladder increases with increasing extension and proximity of these organs to the target. This information can be used during the planning stage to facilitate the plan optimization process, and to standardize plan quality and consistency. We have developed a method for determining customized dose constraints for prostate patients treated with robotic SBRT. Although the results are technology specific and based on the experience of a single institution, we expect that the application of this method by other institutions will result in improved standardization of clinical practice.

Early salvage radiotherapy following radical prostatectomy

CONTEXT

Depending on the pathologic tumour stage, up to 60% of prostate cancer patients who undergo radical prostatectomy will develop biochemical relapse and require further local treatment.

OBJECTIVES

We reviewed the results of early salvage radiation therapy (RT), defined as prostate-specific antigen (PSA) values prior to RT ≤ 0.5 ng/ml in the setting of lymph node-negative disease.

EVIDENCE ACQUISITION

Ten retrospective studies, including one multicentre analysis, were used for this analysis. Among them, we received previously unpublished patient characteristics and updated outcome data from five retrospective single-centre trials to perform a subgroup analysis for early salvage RT.

EVIDENCE SYNTHESIS

Patients treated with early salvage RT have a significantly improved biochemical recurrence-free survival (BRFS) rate compared with those receiving salvage RT initiated after PSA values are >0.5 ng/ml. Similarly, within the cohort of patients with pre-RT PSA values <0.5 ng/ml, improved BRFS rates were noted among those with lower rather higher pre-RT PSA levels. It is possible that higher RT dose levels and the use of adjunctive androgen-deprivation therapy improve biochemical control outcomes in the salvage setting.

CONCLUSIONS

Based on a literature review, improved 5-yr BRFS rates are observed for patients who receive early salvage RT compared with patients treated with salvage RT with a pre-RT PSA value >0.5 ng/ml. Whether the routine application of early salvage RT in patients with initially undetectable PSA levels will be associated with demonstrable clinical benefit awaits the results of ongoing prospective trials.

Overview of randomized controlled treatment trials for clinically localized prostate cancer: implications for active surveillance and the United States preventative task force report on screening?

Prostate cancer and its management have been intensely debated for years. Recommendations range from ardent support for active screening and immediate treatment to resolute avoidance of screening and active surveillance. There is a growing body of level I evidence establishing a clear survival advantage for treatment of subsets of patients with clinically localized prostate cancer. This chapter presents a review of these randomized controlled trials. We argue that an understanding of this literature is relevant not only to those considering active surveillance but also to those evaluating the merits of screening. In addition, a number of important evidence-based conclusions concerning what should and should not be done can be gleaned from these trials.

Adjuvant and salvage radiotherapy after prostatectomy: AUA/ASTRO Guideline

PURPOSE

The purpose of this guideline is to provide a clinical framework for the use of radiotherapy after radical prostatectomy as adjuvant or salvage therapy.

MATERIALS AND METHODS

A systematic literature review using the PubMed®, Embase, and Cochrane databases was conducted to identify peer-reviewed publications relevant to the use of radiotherapy after prostatectomy. The review yielded 294 articles; these publications were used to create the evidence-based guideline statements. Additional guidance is provided as Clinical Principles when insufficient evidence existed.

RESULTS

Guideline statements are provided for patient counseling, the use of radiotherapy in the adjuvant and salvage contexts, defining biochemical recurrence, and conducting a re-staging evaluation.

CONCLUSIONS

Physicians should offer adjuvant radiotherapy to patients with adverse pathologic findings at prostatectomy (i.e., seminal vesicle invasion, positive surgical margins, extraprostatic extension) and should offer salvage radiotherapy to patients with prostatic specific antigen or local recurrence after prostatectomy in whom there is no evidence of distant metastatic disease. The offer of radiotherapy should be made in the context of a thoughtful discussion of possible short- and long-term side effects of radiotherapy as well as the potential benefits of preventing recurrence. The decision to administer radiotherapy should be made by the patient and the multi-disciplinary treatment team with full consideration of the patient's history, values, preferences, quality of life, and functional status. Please visit the ASTRO and AUA websites (http://www.redjournal.org/webfiles/images/journals/rob/RAP%20Guideline.pdf and http://www.auanet.org/education/guidelines/radiation-after-prostatectomy.cfm) to view this guideline in its entirety, including the full literature review.

Vascular endothelial growth factor (VEGF) expression in locally advanced prostate cancer: secondary analysis of radiation therapy oncology group (RTOG) 8610

Background

Angiogenesis is a key element in solid-tumor growth, invasion, and metastasis. VEGF is among the most potent angiogenic factor thus far detected. The aim of the present study is to explore the potential of VEGF (also known as VEGF-A) as a prognostic and predictive biomarker among men with locally advanced prostate cancer.

Methods

The analysis was performed using patients enrolled on RTOG 8610, a phase III randomized control trial of radiation therapy alone (Arm 1) versus short-term neoadjuvant and concurrent androgen deprivation and radiation therapy (Arm 2) in men with locally advanced prostate carcinoma. Tissue samples were obtained from the RTOG tissue repository. Hematoxylin and eosin slides were reviewed, and paraffin blocks were immunohistochemically stained for VEGF expression and graded by Intensity score (0–3). Cox or Fine and Gray’s proportional hazards models were used.

Results

Sufficient pathologic material was available from 103 (23%) of the 456 analyzable patients enrolled in the RTOG 8610 study. There were no statistically significant differences in the pre-treatment characteristics between the patient groups with and without VEGF intensity data. Median follow-up for all surviving patients with VEGF intensity data is 12.2 years. Univariate and multivariate analyses demonstrated no statistically significant correlation between the intensity of VEGF expression and overall survival, distant metastasis, local progression, disease-free survival, or biochemical failure. VEGF expression was also not statistically significantly associated with any of the endpoints when analyzed by treatment arm.

Conclusions

This study revealed no statistically significant prognostic or predictive value of VEGF expression for locally advanced prostate cancer. This analysis is among one of the largest sample bases with long-term follow-up in a well-characterized patient population. There is an urgent need to establish multidisciplinary initiatives for coordinating further research in the area of human prostate cancer biomarkers.

Whole-pelvic nodal radiation therapy in the context of hypofractionation for high-risk prostate cancer patients: a step forward

Given the low α/β ratio of prostate cancer, prostate hypofractionation has been tested through numerous clinical studies. There is a growing body of literature suggesting that with high conformal radiation therapy and even with more sophisticated radiation techniques, such as high-dose-rate brachytherapy or image-guided intensity modulated radiation therapy, morbidity associated with shortening overall treatment time with higher doses per fraction remains low when compared with protracted conventional radiation therapy to the prostate only. In high-risk prostate cancer patients, there is accumulating evidence that either dose escalation to the prostate or hypofractionation may improve outcome. Nevertheless, selected patients who have a high risk of lymph node involvement may benefit from whole-pelvic radiation therapy (WPRT). Although combining WPRT with hypofractionated prostate radiation therapy is feasible, it remains investigational. By combining modern advances in radiation oncology (high-dose-rate prostate brachytherapy, intensity modulated radiation therapy with an improved image guidance for soft-tissue sparing), it is hypothesized that WPRT could take advantage of recent results from hypofractionation trials. Moreover, the results from hypofractionation trials raise questions as to whether hypofractionation to pelvic lymph nodes with a high risk of occult involvement might improve the outcomes in WPRT. Although investigational, this review discusses the challenging idea of WPRT in the context of hypofractionation for patients with high-risk prostate cancer.

Prostate-specific antigen response after short-term hormone therapy plus external-beam radiotherapy and outcome in patients treated on Radiation Therapy Oncology Group study 9413

BACKGROUND

The objective of this study was to assess the impact of a prostate-specific antigen (PSA) complete response (PSA-CR), measured at the end of external-beam radiotherapy and short-term hormone therapy, on treatment outcomes.

METHODS

The phase 3 Radiation Therapy Oncology Group 9413 trial, as part of its original protocol, used the assessment of PSA-CR (ie, PSA ≤0.3 ng/mL) at the end of short-term HT as a secondary endpoint. Short-term HT consisted of futamide plus a lutenizing hormone-releasing hormone agonist for 4 months. The Kaplan-Meier method was used to estimate overall survival (OS) and disease-free survival. Cumulative incidence was used to estimate biochemical failure, distant metastasis, and disease-specific survival. Univariate and multivariate analyses were performed to correlate PSA-CR after short-term hormone therapy with all endpoints, and the following variables were considered for analysis: PSA at baseline, Gleason score, treatment arm, age, and baseline testosterone status. Phoenix consensus definition was used to define PSA failure.

RESULTS

For 1070 evaluable patients, the median PSA at the end of short-term hormone therapy was 0.2 ng/mL. In total, 744 patients (70%) had a PSA-CR. At a median follow-up of 7.2 years, failure to obtain a PSA-CR was associated significantly with worse disease-specific survival (P = .0003; hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.38-2.97), with worse disease-free survival (P = .003; HR, 1.28; 95% CI, 1.09-1.50), and with a higher incidence of distant metastasis (P = .0002; HR, 1.92; 95% CI, 1.37-2.69) and biochemical failure (P < .0001; HR, 1.57; 95% CI, 1.29-1.91). Other factors that were associated with worse disease-specific survival were Gleason scores from 8 to 10 (P = .0002; HR, 3.06; 95% CI, 1.71-5.47) and PSA levels >20 ng/mL (P = .04; HR, 1.55; 95% CI, 1.02-2.30).

CONCLUSIONS

The current results indicated that failure to obtain a PSA-CR (PSA ≤0.3 ng/mL) after short-term hormone therapy and external-beam radiotherapy appears to be an independent predictor of unfavorable outcomes and could help identify patients who may benefit from the addition of long-term androgen ablation.

Comparison of PSA slope and nadir between hypofractionated SBRT and conventionally fractionated EBRT

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Background: Patients with early stage prostate cancer have a challenge in selecting from a variety of curative radiotherapy options, including external beam radiotherapy (EBRT) and hypofractionated stereotactic body radiotherapy (SBRT). Rapid post-treatment PSA decline and low PSA nadir have been associated with improved clinical outcomes. The purpose of this study was to compare the PSA measurements over time between conventionally fractionated EBRT and SBRT in newly diagnosed localized prostate cancer. Methods: 104 patients with low to low-intermediate risk prostate cancer (GS 3+3, PSA < 20 or 3+4, PSA < 15) treated with standard fractionated EBRT (> 70.2 Gy, < 76 Gy) without hormones to the prostate only were identified from a prospectively collected cohort of patients treated at the University of California, San Francisco (1997-2012). Patients were excluded if they failed therapy by the Phoenix definition. All included patients had at least 1 year of follow up and 3 serial PSAs. 35 patients that were treated with SBRT to the prostate to 38 Gy in 4 daily fractions also met the same criteria. Of these, 47 and 19 patients treated with EBRT and SBRT, respectively, had a yearly increase in PSA follow-up over 3 years. PSA nadir and rate of change in PSA over time (e.g. slope) were calculated from the completion of RT to 1, 2 and 3 years post RT. Results: The median PSA nadir and slope for patients treated with EBRT was 0.80, 0.50, 0.40 ng and ‑0.07, ‑0.02, ‑0.01 ng/ml/month, respectively, for durations of 1, 2 and 3 years post RT. Similarly, for SBRT, the median PSA nadir and slope were 0.73, 0.50, 0.24 ng and ‑0.09, ‑0.06, ‑0.05 ng/ml/month. The PSA slope for SBRT was greater than EBRT (p = 0.001) at 2 and 3 years following RT, although similar during the first year. These results were consistent when limited to patients with more complete PSA follow-up each year, with PSA nadir significantly lower 3 years after treatment with SBRT compared with EBRT (p = 0.03). Conclusions: Patients treated with SBRT experienced a more rapid decline in PSA 2 and 3 years following completion of RT than with EBRT, and for those with continuous long term followup, a lower PSA nadir, consistent with delivery of a higher bioequivalent dose.

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.

Clinical outcome of patients treated with 3D conformal radiation therapy (3D-CRT) for prostate cancer on RTOG 9406

PURPOSE

Report of clinical cancer control outcomes on Radiation Therapy Oncology Group (RTOG) 9406, a three-dimensional conformal radiation therapy (3D-CRT) dose escalation trial for localized adenocarcinoma of the prostate.

METHODS AND MATERIALS

RTOG 9406 is a Phase I/II multi-institutional dose escalation study of 3D-CRT for men with localized prostate cancer. Patients were registered on five sequential dose levels: 68.4 Gy, 73.8 Gy, 79.2 Gy, 74 Gy, and 78 Gy with 1.8 Gy/day (levels I-III) or 2.0 Gy/day (levels IV and V). Neoadjuvant hormone therapy (NHT) from 2 to 6 months was allowed. Protocol-specific, American Society for Therapeutic Radiation Oncology (ASTRO), and Phoenix biochemical failure definitions are reported.

RESULTS

Thirty-four institutions enrolled 1,084 patients and 1,051 patients are analyzable. Median follow-up for levels I, II, III, IV, and V was 11.7, 10.4, 11.8, 10.4, and 9.2 years, respectively. Thirty-six percent of patients received NHT. The 5-year overall survival was 90%, 87%, 88%, 89%, and 88% for dose levels I-V, respectively. The 5-year clinical disease-free survival (excluding protocol prostate-specific antigen definition) for levels I-V is 84%, 78%, 81%, 82%, and 82%, respectively. By ASTRO definition, the 5-year disease-free survivals were 57%, 59%, 52%, 64% and 75% (low risk); 46%, 52%, 54%, 56%, and 63% (intermediate risk); and 50%, 34%, 46%, 34%, and 61% (high risk) for levels I-V, respectively. By the Phoenix definition, the 5-year disease-free survivals were 68%, 73%, 67%, 84%, and 80% (low risk); 70%, 62%, 70%, 74%, and 69% (intermediate risk); and 42%, 62%, 68%, 54%, and 67% (high risk) for levels I-V, respectively.

CONCLUSION

Dose-escalated 3D-CRT yields favorable outcomes for localized prostate cancer. This multi-institutional experience allows comparison to other experiences with modern radiation therapy.

Management of prostate cancer patients with lymph node involvement: a rapidly evolving paradigm

Although widespread PSA screening has inevitably led to increased diagnosis of lower risk prostate cancer, the number of patients with nodal involvement at baseline remains high (nearly 40% of high risk patients initially staged cN0). These rates probably do not reflect the true incidence of prostate cancer with lymph node involvement among patients selected for external beam radiotherapy (EBRT), as patients selected for surgery often have more favorable prognostic features. At many institutions, radical treatment directed only at the prostate is considered standard and patients known to have regional disease are often managed palliatively with androgen deprivation therapy (ADT) for presumed systemic disease. New imaging tools such as MR lymphangiography, choline-based PET imaging or combined SPECT/CT now allow surgeons and radiation oncologists to identify and target nodal metastasis and/or lymph nodes with a high risk of occult involvement. Recent advances in the field of surgery including the advent of extended nodal dissection and sentinel node procedures have suggested that cancer-specific survival might be improved for lymph-node positive patients with a low burden of nodal involvement when managed with aggressive interventions. These new imaging tools can provide radiation oncologists with maps to guide delivery of high dose conformal radiation to a target volume while minimizing radiation toxicity to non-target normal tissue. This review highlights advances in imaging and reports how they may help to define a new paradigm to manage node-positive prostate cancer patients with a curative-intent.

Magnetic resonance lymphography findings in patients with biochemical recurrence after prostatectomy and the relation with the Stephenson nomogram

PURPOSE

To estimate the occurrence of positive lymph nodes on magnetic resonance lymphography (MRL) in patients with a prostate-specific antigen (PSA) recurrence after prostatectomy and to investigate the relation between score on the Stephenson nomogram and lymph node involvement on MRL.

METHODS AND MATERIALS

Sixty-five candidates for salvage radiation therapy were referred for an MRL to determine their lymph node status. Clinical and histopathologic features were recorded. For 49 patients, data were complete to calculate the Stephenson nomogram score. Receiver operating characteristic (ROC) analysis was performed to determine how well this nomogram related to the MRL result. Analysis was done for the whole group and separately for patients with a PSA <1.0 ng/mL to determine the situation in candidates for early salvage radiation therapy, and for patients without pathologic lymph nodes at initial lymph node dissection.

RESULTS

MRL detected positive lymph nodes in 47 patients. ROC analysis for the Stephenson nomogram yielded an area under the curve (AUC) of 0.78 (95% confidence interval, 0.61-0.93). Of 29 patients with a PSA <1.0 ng/mL, 18 had a positive MRL. Of 37 patients without lymph node involvement at initial lymph node dissection, 25 had a positive MRL. ROC analysis for the Stephenson nomogram showed AUCs of 0.84 and 0.74, respectively, for these latter groups.

CONCLUSION

MRL detected positive lymph nodes in 72% of candidates for salvage radiation therapy, in 62% of candidates for early salvage radiation therapy, and in 68% of initially node-negative patients. The Stephenson nomogram showed a good correlation with the MRL result and may thus be useful for identifying patients with a PSA recurrence who are at high risk for lymph node involvement.

Does local recurrence of prostate cancer after radiation therapy occur at the site of primary tumor? Results of a longitudinal MRI and MRSI study

PURPOSE

To determine if local recurrence of prostate cancer after radiation therapy occurs at the same site as the primary tumor before treatment, using longitudinal magnetic resonance (MR) imaging and MR spectroscopic imaging to assess dominant tumor location.

METHODS AND MATERIALS

This retrospective study was HIPAA compliant and approved by our Committee on Human Research. We identified all patients in our institutional prostate cancer database (1996 onward) who underwent endorectal MR imaging and MR spectroscopic imaging before radiotherapy for biopsy-proven prostate cancer and again at least 2 years after radiotherapy (n = 124). Two radiologists recorded the presence, location, and size of unequivocal dominant tumor on pre- and postradiotherapy scans. Recurrent tumor was considered to be at the same location as the baseline tumor if at least 50% of the tumor location overlapped. Clinical and biopsy data were collected from all patients.

RESULTS

Nine patients had unequivocal dominant tumor on both pre- and postradiotherapy imaging, with mean pre- and postradiotherapy dominant tumor diameters of 1.8 cm (range, 1-2.2) and 1.9 cm (range, 1.4-2.6), respectively. The median follow-up interval was 7.3 years (range, 2.7-10.8). Dominant recurrent tumor was at the same location as dominant baseline tumor in 8 of 9 patients (89%).

CONCLUSIONS

Local recurrence of prostate cancer after radiation usually occurs at the same site as the dominant primary tumor at baseline, suggesting supplementary focal therapy aimed at enhancing local tumor control would be a rational addition to management.

Radiation Therapy Oncology Group (RTOG) 9413: Randomized trial comparing whole pelvic radiotherapy (WPRT) to prostate only (PORT) and neoadjuvant hormone therapy (NHT) to adjuvant hormone therapy (AHT)

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Background: RTOG 9413 demonstrated that NHT+WPRT improved progression-free survival (PFS) compared to NHT+PORT, WPRT+AHT and PORT+AHT. We update primary and secondary endpoints (SE): biochemical failure (BF), time to metastasis (Mets), prostate specific survival (PSS) and overall survival (OS).

Methods: RTOG 9413 opened on April 1, 1995, and closed on June 1, 1999, with 1275 eligible pts who were required to have a risk of lymph node (LN) involvement >15% but LN-positive pts were ineligible. They were stratified by T Stage, GS (<7 vs 7-10) and PSA (>30 vs < 30ng/ml) and randomized to PORT +/- WPRT to 70 Gy and NHT or AHT. Hormonal therapy (HT) consisted of flutamide, and leuprolide or goserelin, monthly x 4 mos, beginning 2 mos before RT and continued until RT is completed (NHT) or beginning at the completion of RT (AHT). For this analysis PFS was defined as the first occurrence of local/regional or LN progression, Mets, BF (PSA nadir+2ng/mL), or death from any cause. PSS is defined as a death due to prostate cancer, treatment toxicity or unknown causes with local progression, Mets or BF.

Results: For the entire cohort WPRT or NHT did not appear to improve any endpoint compared with PORT or AHT, (although there was a trend for improvement in regional failure for WPRT vs PORT, (p=0.07)). However, there were complex sequence/volume dependent interactions between HT and RT and statistically significant differences between the 4 arms in PFS (p=0.03). There was a trend for NHT+WPRT to improved PFS compared to NHT+PO (p=0.07) and WPRT+AHT (p=0.04). NHT+WPRT was associated with an increased risk of late GI toxicity, 5% compared to 0.6%, 2% and 2% for NHT+PORT, WPRT+AHT and PORT+AHT (p<0.001) but not in GU late toxicity.

Conclusions: The failure to improve SE or definitively impact PFS may reflect sample size, pt selection, and inadequate RT doses. RTOG 0924 will test the hypotheses that modern techniques and doses will improve OS without increasing late toxicity.

Indications and practice with androgen deprivation therapy

The Cancer of the Prostate Strategic Urological Research Endeavor (CaPSURE) is an ongoing longitudinal observational study of current trends in prostate cancer staging and treatment across a spectrum of different treatment facilities in the United States. To date, the study has documented 2 principal findings: (a) a large variation exists in the treatment choices applied to similar patient presentations across the range of facility type, size, and geographic location in the United States; and (b) although it does not seem to make much difference in mortality outcomes which approach--hormonal therapy, radiotherapy, or surgery--is applied to men at low or intermediate risk, a survival benefit exists with surgery for men at high risk.

Temporal compartmental dosing effects for robotic prostate stereotactic body radiotherapy

The rate of dose accumulation within a given area of a target volume tends to vary significantly for non-isocentric delivery systems such as Cyberknife stereotactic body radiotherapy. In this study, we investigated whether intra-target temporal dose distributions produce significant variations in the biological equivalent dose. For the study, time courses of ten patients were reconstructed and calculation of a biologically equivalent uniform dose (EUD) was performed using a formula derived from the linear quadratic model (α/β = 3 for prostate cancer cells). The calculated EUD values obtained for the actual patient treatments were then compared with theoretical EUD values for delivering the same physical dose distribution except that the whole target being irradiated continuously (e.g. large-field 'dose-bathing' type of delivery). For all the case, the EUDs for the actual treatment delivery were found to correlate strongly with the EUDs for the large-field delivery: a linear correlation coefficient of R² = 0.98 was obtained and the average EUD for the actual Cyberknife delivery was somewhat higher (5.0 ± 4.7%) than that for the large-field delivery. However, no statistical significance was detected between the two types of delivery (p = 0.21). We concluded that non-isocentric small-field Cyberknife delivery produced consistent biological dosing that tracked well with the constant-dose-rate, large-field-type delivery for prostate stereotactic body radiotherapy.

Endorectal MRI after radiation therapy: questioning the sextant analysis

PURPOSE

To evaluate whether the information gained by three coregistration systems (sextant, hemi-prostate, and whole gland) differs significantly, suggesting that one approach should be routinely favored over the others. Despite its known limitations, sextant is the generally accepted standard for magnetic resonance imaging (MRI) and biopsy coregistration; nevertheless, depending on the magnitude of localization errors, other options may be adequate.

MATERIALS AND METHODS

Institutional Review Board approval was obtained and the study was Health Insurance Portability and Accountability Act (HIPAA)-compliant. We identified 70 patients who underwent 1.5 T endorectal MRI of the prostate between 1999 and 2008 after external beam radiotherapy for prostate cancer. A single reader reviewed all T2-weighted images for the presence or absence of tumor. The performance of each approach was quantified using receiver operating characteristic (ROC) curve analysis. Transrectal ultrasound-guided sextant biopsies were used as a standard of reference.

RESULTS

The areas under the ROC curve indicating accuracy for each MRI approach were 0.63 (sextant), 0.68 (hemi-prostate), and 0.71 (whole gland). There was no statistically significant difference among these approaches.

CONCLUSION

As expected, the point estimate was higher for the whole-gland approach, but not significantly. Reliable assessment of locally recurrent prostate cancer after external beam radiotherapy by endorectal MRI may be made using a sextant, hemi-prostate, or whole gland approach. The option for one or another approach should not be solely based on estimations of imaging accuracy, but on the purpose of the procedure.

Promoting wellness for patients on androgen deprivation therapy: why using numerous drugs for drug side effects should not be first-line treatment

The controversy over androgen deprivation therapy (ADT) for prostate cancer seems to have shifted over the past decade. The issue of adverse events or side effects now seems to dominate over that of clinical efficacy. However, this article provides evidence that questions the treatment of these side effects with numerous prescription medications that have their own unique toxicity profile in patients with nonmetastatic disease. The hope is that patients will no longer be considered passive participants in the prevention and treatment of ADT side effects, now that information is available to help mitigate many of these effects.

Validation of a Predictive Model for Survival in Patients With Advanced Cancer: Secondary Analysis of RTOG 9714

Background

The objective of this study was to validate a simple predictive model for survival of patients with advanced cancer.

Methods

Previous studies with training and validation datasets developed a model predicting survival of patients referred for palliative radiotherapy using three readily available factors: primary cancer site, site of metastases and Karnofsky performance score (KPS). This predictive model was used in the current study, where each factor was assigned a value proportional to its prognostic weight and the sum of the weighted scores for each patient was survival prediction score (SPS). Patients were also classified according to their number of risk factors (NRF). Three risk groups were established. The Radiation Therapy and Oncology Group (RTOG) 9714 data was used to provide an additional external validation set comprised of patients treated among multiple institutions with appropriate statistical tests.

Results

The RTOG external validation set comprised of 908 patients treated at 66 different radiation facilities from 1998 to 2002. The SPS method classified all patients into the low-risk group. Based on the NRF, two distinct risk groups with significantly different survival estimates were identified. The ability to predict survival was similar to that of the training and previous validation datasets for both the SPS and NRF methods.

Conclusions

The three variable NRF model is preferred because of its relative simplicity.

Pelvic nodal radiotherapy in patients with unfavorable intermediate and high-risk prostate cancer: evidence, rationale, and future directions

Over the past 15 years, there have been three major advances in the use of external beam radiotherapy in the management of men with clinically localized prostate made. They include: (1) image guided (IG) three-dimensional conformal/intensity modulated radiotherapy; (2) radiation dose escalation; and (3) androgen deprivation therapy. To date only the last of these three advances have been shown to improve overall survival. The presence of occult pelvic nodal involvement could explain the failure of increased conformality and dose escalation to prolong survival, because the men who appear to be at the greatest risk of death from clinically localized prostate cancer are those who are likely to have lymph node metastases. This review discusses the evidence for prophylactic pelvic nodal radiotherapy, including the key trials and controversies surrounding this issue.

Diagnostic and therapeutic imaging for cancer: therapeutic considerations and future directions

As cancer treatment cost soar and the mantra for "personalized medicine" grows louder, we will increasingly be searching for solutions to these diametrically opposed forces. In this review we highlight several exciting novel imaging strategies including MRI, CT, PET SPECT, sentinel node, and ultrasound imaging that hold great promise for improving outcomes through detection of lymph node involvement. We provide clinical data that demonstrate how these evolving strategies have the potential to transform treatment paradigms.

Older age predicts decreased metastasis and prostate cancer-specific death for men treated with radiation therapy: meta-analysis of radiation therapy oncology group trials

PURPOSE

The impact of age on prostate cancer (PCa) outcome has been controversial; therefore, we analyzed the effect of age on overall survival (OS), distant metastasis, prostate cancer-specific death (PCSD), and nonprostate cancer death (NPCD) on patients with locally advanced PCa.

METHODS AND MATERIALS

Patients who participated in four Radiation Therapy Oncology Group (RTOG) phase III trials, 8531, 8610, 9202, and 9413, were studied. Cox proportional hazards regression was used for OS analysis, and cumulative events analysis with Fine and Gray's regression was used for analyses of metastasis, PCSD, and NPCD.

RESULTS

Median follow-up of 4,128 patients with median age of 70 (range, 43-88 years) was 7.3 years. Most patients had high-risk disease: cT3 to cT4 (54%) and Gleason scores (GS) of 7 (45%) and 8 to 10 (27%). Older age (≤70 vs. >70 years) predicted for decreased OS (10-year rate, 55% vs. 41%, respectively; p<0.0001) and increased NPCD (10-year rate, 28% vs. 46%, respectively; p<0.0001) but decreased metastasis (10-year rate, 27% vs. 20%, respectively; p<0.0001) and PCSD (10-year rate, 18% vs. 14%, respectively; p<0.0001). To account for competing risks, outcomes were analyzed in 2-year intervals, and age-dependent differences in metastasis and PCSD persisted, even in the earliest time periods. When adjusted for other covariates, an age of >70 years remained associated with decreased OS (hazard ratio [HR], 1.56 [95% confidence interval [CI], 1.43-1.70] p<0.0001) but with decreased metastasis (HR, 0.72 [95% CI, 0.63-0.83] p<0.0001) and PCSD (HR, 0.78 [95% CI, 0.66-0.92] p<0.0001). Finally, the impact of the duration of androgen deprivation therapy as a function of age was evaluated.

CONCLUSIONS

These data support less aggressive PCa in older men, independent of other clinical features. While the biological underpinning of this finding remains unknown, stratification by age in future trials appears to be warranted.

Disease-specific survival outcomes in lymph node–positive patients with prostate cancer treated with radiotherapy

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Background: Involvement of regional lymph nodes (LN+) at the time of prostate cancer (PCa) diagnosis is widely regarded as an adverse prognostic factor associated with poor outcome. No commonly utilized treatment, composed of any combination of androgen ablation, surgery and radiation, has proven to be superior for survival. This study will evaluate the clinical survival outcomes of patients (pts) with newly diagnosed LN+ PCa at the University of California San Francisco (UCSF).

Methods: All newly diagnosed LN+ PCa pts treated with External Beam Radiation Therapy (EBRT) as primary therapy or after surgery, each with and without androgen ablation between 1987 and 2009 were included. All pts had confirmed pathologic or radiologic LN+ whereas none had evidence of metastases on the work up. Cause Specific Survival (CSS), Disease Free survival (DFS) and biochemical control were measured from the start of treatment. PSA failure was determined by the Phoenix definition after EBRT and by a confirmed PSA >1 ng/mL following RP+EBRT.

Results: A retrospective analysis identified 91 pts with LN+ at the time of diagnosis (75.8% high risk pts) with disease follow-up. Thirty-four (37%) were managed with exclusive EBRT alone (eRT), 18 pts (20%) with a combination of radical prostatectomy (RP) and adjuvant EBRT (RP+aRT) and 39 pts (43%) were treated with a combination of RP + salvage RT (RP+sRT). Overall 78% of patients also received hormone therapy (HT): 74.0% with eRT, 89% with RP+aRT and 79% with RP+sRT. The 10 years CSS estimates was 89% for eRT, 0% after RP+aRT and 88% after RP+sRT. The 10 years DFS estimates was 33% for eRT, 0% after RP+aRT and 75% after RP+sRT. Among pts remaining disease free the median follow-up is 38 mos for eRT, 26 mos for RP+aRT and 64 mos for RP+sRT. The last PSA for these patients was <0.1 for 85% of all patients which included 47% following eRT, 100% after RP+aRT and 97% after RP+sRT. There were 7 deaths due to PCa occurring between 5 and 73 mos from the start of EBRT.

Conclusions: The results of the current analysis indicate that some pts with LN+ from PCa have prolonged disease free outcomes; and for these men, aggressive treatment may be appropriate.

No significant financial relationships to disclose.

Successful radiation treatment of anaplastic thyroid carcinoma metastatic to the right cardiac atrium and ventricle in a pacemaker-dependent patient

Anaplastic thyroid carcinoma (ATC) is a rare, aggressive malignancy, which is known to metastasize to the heart. We report a case of a patient with ATC with metastatic involvement of the pacemaker leads within the right atrium and right ventricle. The patient survived external beam radiation treatment to his heart, with a radiographic response to treatment. Cardiac metastases are usually reported on autopsy; to our knowledge, this is the first report of the successful treatment of cardiac metastases encasing the leads of a pacemaker, and of cardiac metastases from ATCs, with a review of the pertinent literature.