Improved freedom from PSA failure with whole pelvic irradiation for high-risk prostate cancer

Efficacy and Toxicity of Whole Pelvic Radiotherapy Versus Prostate-Only Radiotherapy in Localized Prostate Cancer: A Systematic Review and Meta-Analysis

Background

There is little level 1 evidence regarding the relative efficacy and toxicity of whole pelvic radiotherapy (WPRT) compared with prostate-only radiotherapy (PORT) for localized prostate cancer.

Methods

We used Cochrane, PubMed, Embase, Medline databases, and ClinicalTrials.gov to systematically search for all relevant clinical studies. The data on efficacy and toxicity were extracted for quality assessment and meta-analysis to quantify the effect of WPRT on biochemical failure-free survival (BFFS), progression-free survival (PFS), distant metastasis-free survival (DMFS), overall survival (OS), gastrointestinal (GI) toxicity, and genitourinary (GU) toxicity compared with PORT. The review is registered on PROSPERO, number: CRD42021254752.

Results

The results revealed that compared with PORT, WPRT significantly improved 5-year BFFS and PFS, and it was irrelevant to whether the patients had undergone radical prostatectomy (RP). In addition, for the patients who did not receive RP, the 5-year DMFS of WPRT was better than that of PORT. However, WPRT significantly increased not only the grade 2 or worse (G2+) acute GI toxicity of non-RP studies and RP studies, but also the G2+ late GI toxicity of non-RP studies. Subgroup analysis of non-RP studies found that, when the pelvic radiation dose was >49 Gy (equivalent-doses-in-2-Gy-fractions, EQD-2), WPRT was more beneficial to PFS than PORT, but significantly increased the risk of G2+ acute and late GU toxicity.

Conclusions

Meta-analysis demonstrates that WPRT can significantly improve BFFS and PFS for localized prostate cancer than PORT, but the increased risk of G2+ acute and late GI toxicity must be considered.

Systematic Review Registration

PROSPERO CRD42021254752.

68Ga-PSMA-11 PET has the potential to improve patient selection for extended pelvic lymph node dissection in intermediate to high-risk prostate cancer

INTRODUCTION

Radical prostatectomy with extended pelvic lymph node dissection (ePLND) is a curative treatment option for patients with clinically significant localised prostate cancer. The decision to perform an ePLND can be challenging because the overall incidence of lymph node metastasis is relatively low and ePLND is not free of complications. Using current clinical nomograms to identify patients with nodal involvement, approximately 75-85% of ePLNDs performed are negative. The aim of this study was to assess the added value of ⁶⁸Ga-PSMA-11 PET in predicting lymph node metastasis in men with intermediate- or high-risk prostate cancer.

METHODS

⁶⁸Ga-PSMA-11 PET scans of 60 patients undergoing radical prostatectomy with ePLND were reviewed for qualitative (visual) assessment of suspicious nodes and assessment of quantitative parameters of the primary tumour in the prostate (SUV_max, total activity (PSMA_total) and PSMA positive volume (PSMA_vol)). Ability of quantitative PET parameters to predict nodal metastasis was assessed with receiver operating characteristics (ROC) analysis. A multivariable logistic regression model combining PSA, Gleason score, visual nodal status on PET and primary tumour PSMA_total was built. Net benefit at each risk threshold was compared with five nomograms: MSKCC nomogram, Yale formula, Roach formula, Winter nomogram and Partin tables (2016).

RESULTS

Overall, pathology of ePLND specimens revealed 31 pelvic metastatic lymph nodes in 12 patients. ⁶⁸Ga-PSMA-11 PET visual analysis correctly detected suspicious nodes in 7 patients, yielding a sensitivity of 58% and a specificity of 98%. The area under the ROC curve for primary tumour SUV_max was 0.70, for PSMA_total 0.76 and for PSMA_vol 0.75. The optimal cut-off for nodal involvement was PSMA_total > 49.1. The PET model including PSA, Gleason score and quantitative PET parameters had a persistently higher net benefit compared with all clinical nomograms.

CONCLUSION

Our model combining PSA, Gleason score and visual lymph node analysis on ⁶⁸Ga-PSMA-11 PET with PSMA_total of the primary tumour showed a tendency to improve patient selection for ePLND over the currently used clinical nomograms. Although this result has to be validated, ⁶⁸Ga-PSMA-11 PET showed the potential to reduce unnecessary surgical procedures in patients with intermediate- or high-risk prostate cancer.

[Prophylactic nodal radiotherapy in prostate cancer]

The risk of lymph node invasion, in case of prostate cancer, increases with the clinical stage of the disease, the Gleason score of prostate biopsies and the value of PSA at diagnosis. Historically, beyond 15% risk of lymph node involvement, irradiation of the pelvic areas was performed with prostate radiotherapy (RT) to take into account the risk of occult lymph node metastasis in patients at risk, but the benefit of this therapeutic approach remains to be demonstrated. The data from surgical lymph node dissection seem to question the risk levels, the escalation of the dose on the prostate increases the survival without relapse, the contribution of image-guided radiotherapy, (IGRT) and modulation of intensity (IMRT), decreases the toxicity of pelvic RT. This article reviews the principles of prophylactic ganglion irradiation for prostate cancer and discusses its relevance, current uncertainties, and prospective trials.

Prostate-only Versus Whole-pelvis Radiation with or Without a Brachytherapy Boost for Gleason Grade Group 5 Prostate Cancer: A Retrospective Analysis

BACKGROUND

The role of elective whole-pelvis radiotherapy (WPRT) remains controversial. Few studies have investigated it in Gleason grade group (GG) 5 prostate cancer (PCa), known to have a high risk of nodal metastases.

OBJECTIVE

To assess the impact of WPRT on patients with GG 5 PCa treated with external-beam radiotherapy (EBRT) or EBRT with a brachytherapy boost (EBRT+BT).

DESIGN, SETTING, AND PARTICIPANTS

We identified 1170 patients with biopsy-proven GG 5 PCa from 11 centers in the United States and one in Norway treated between 2000 and 2013 (734 with EBRT and 436 with EBRT+BT).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Biochemical recurrence-free survival (bRFS), distant metastasis-free survival (DMFS), and prostate cancer-specific survival (PCSS) were compared using Cox proportional hazards models with propensity score adjustment.

RESULTS AND LIMITATIONS

A total of 299 EBRT patients (41%) and 320 EBRT+BT patients (73%) received WPRT. The adjusted 5-yr bRFS rates with WPRT in the EBRT and EBRT+BT groups were 66% and 88%, respectively. Without WPRT, these rates for the EBRT and EBRT+BT groups were 58% and 78%, respectively. The median follow-up was 5.6yr. WPRT was associated with improved bRFS among patients treated with EBRT+BT (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.2-0.9, p=0.02), but no evidence for improvement was found in those treated with EBRT (HR 0.8, 95% CI 0.6-1.2, p=0.4). WPRT was not significantly associated with improved DMFS or PCSS in the EBRT group (HR 1.1, 95% CI 0.7-1.7, p=0.8 for DMFS and HR 0.7, 95% CI 0.4-1.1, p=0.1 for PCSS), or in the EBRT+BT group (HR 0.6, 95% CI 0.3-1.4, p=0.2 for DMFS and HR 0.5 95% CI 0.2-1.2, p=0.1 for PCSS).

CONCLUSIONS

WPRT was not associated with improved PCSS or DMFS in patients with GG 5 PCa who received either EBRT or EBRT+BT. However, WPRT was associated with a significant improvement in bRFS among patients receiving EBRT+BT. Strategies to optimize WPRT, potentially with the use of advanced imaging techniques to identify occult nodal disease, are warranted.

PATIENT SUMMARY

When men with a high Gleason grade prostate cancer receive radiation with external radiation and brachytherapy, the addition of radiation to the pelvis results in a longer duration of prostate-specific antigen control. However, we did not find a difference in their survival from prostate cancer or in their survival without metastatic disease. We also did not find a benefit for radiation to the pelvis in men who received radiation without brachytherapy.

Acute and Late Toxicity after Moderate Hypofractionation with Simultaneous Integrated Boost (SIB) Radiation Therapy for Prostate Cancer. A Single Institution, Prospective Study

ASBTRACT

To evaluate the acute and late toxicity using moderately hypofractionated, intensity-modulated radiotherapy (IMRT) with a simultaneous integrated boost (SIB) to prostate for patients with intermediate and high risk prostate cancer. From 2015 to 2017, 162 patients were treated with IMRT with SIB to the prostate. IMRT plans were designed to deliver 50.4Gy in 28 fractions (1.8 Gy/fraction) to the pelvic lymph nodes (whole pelvis radiotherapy, WPRT) while simultaneously delivering 57.4 Gy in 28 fractions (2.05 Gy/fraction) to the seminal vesicles and 70 Gy in 28 fractions (2.5 Gy/fraction) to the prostate for high risk patients. For intermediate risk patients the same technique was applied, without WPRT. Acute and cumulative late genitourinary (GU) and gastrointestinal (GI) toxicities were scored according to the Radiation Therapy Oncology Group (RTOG) scoring system. Of the 162 patients enrolled, 156 (96%) completed the treatment as planned. The median follow-up time was 30 months. Seventy-eight patients (48.2%) were treated with WPRT. The rate of acute grade ≥ 2 GI and GU toxicities in all patients were 22% and 58%, respectively. The rate of cumulative late grade ≥ 2 GI and GU toxicities were 11% and 17%, respectively. Acute grade 3 GI and GU toxicities occurred in 1% and 1%. Late grade 3 GI and GU side effects occurred in 5% and 4%, respectively. None of the patients developed grade ≥ 4 toxicity. IMRT with SIB technique using moderate hypofractionation to the prostate is feasible treatment option for intermediate and high risk patients, associated with low rate of severe GU and GI toxicities.

Comparison of Endorectal Magnetic Resonance Imaging, Clinical Prognostic Factors and Nomograms in the Local Staging of Prostate Cancer Patients Treated with Radiotherapy

Aims and background

To determine retrospectively the role of endorectal magnetic resonance in the staging of prostate cancer. The aim of the study was to assess whether it is possible to identify a group of patients with prostate cancer, chosen for certain prognostic factors, eligible for radiotherapy that could take advantage of endorectal magnetic resonance in staging and therapy management.

Methods

Between January 2002 and December 2005, 143 patients with biopsy proven prostate cancer underwent endorectal magnetic resonance. All patients were initially evaluated considering the following prognostic factors: serum prostate-specific antigen at diagnosis, Gleason score, histological grade, involvement of the seminal vesicle and extracapsular extension using the Roach III and ECE equations. The findings were then compared to the results of endorectal magnetic resonance.

Results

The relationship between the variable post-endorectal magnetic resonance stage modification and Gleason score was statistically significant (P = 0.02847). In addition, our study showed a statistically significant correlation between the risk of seminal vesicle involvement according to the Roach III formula and post-endorectal magnetic resonance stage modification (P = 0.01305). Conversely, statistical analysis showed no significant correlation between post-endorectal magnetic resonance stage modification and prostate-specific antigen values (P = 0.83440) or between post-endorectal magnetic resonance stage modification and the risk of extracapsular extension according to the extracapsular extension formula (P = 0.42748).

Conclusions

Our data suggest that endorectal magnetic resonance could be used for staging of the subgroup of patients at high risk of seminal vesicle involvement (>15%). Although we found a statistical correlation between Gleason score and post-endorectal magnetic resonance stage modification, statistical analysis showed no correlation between any of the subgroups. Therefore, it is not possible at the moment to identify a subgroup of patients by Gleason score that may benefit from endorectal magnetic resonance. In our opinion, extracapsular extension values were not useful to select patients for endorectal magnetic resonance.

Progress in SPECT/CT Imaging of Prostate Cancer

Prostate cancer is the most common type of cancer (other than skin cancer) among men in the United States. Although prostate cancer is one of the few cancers that grow so slowly that it may never threaten the lives of some patients, it can be lethal once metastasized. Indium-111 capromab pendetide (ProstaScint®, Cytogen Corporation, Princeton, NJ) imaging is indicated for staging and recurrence detection of the disease, and is particularly useful to determine whether or not the disease has spread to distant metastatic sites. However, the interpretation of 111 In-capromab pendetide is challenging without correlated structural information mostly because the radiopharmaceutical demonstrates nonspecific uptake in the normal vasculature, bowel, bone marrow, and the prostate gland. We developed an improved method of imaging and localizing 111 In-Capromab pendetide using a SPECT/CT imaging system. The specific goals included: i) development and application of a novel iterative SPECT reconstruction algorithm that utilizes a priori information from coregistered CT; and ii) assessment of clinical impact of adding SPECT/CT for prostate cancer imaging with capromab pendetide utilizing the standard and novel reconstruction techniques.

Patient imaging studies with capromab pendetide were performed from 1999 to 2004 using two different SPECT/CT scanners, a prototype SPECT/CT system and a commercial SPECT/CT system (Discovery VH, GE Healthcare, Waukesha, WI). SPECT projection data from both systems were reconstructed using an experimental iterative algorithm that compensates for both photon attenuation and collimator blurring. In addition, the data obtained from the commercial system were reconstructed with attenuation correction using an OSEM reconstruction supplied by the camera manufacturer for routine clinical interpretation. For 12 sets of patient data, SPECT images reconstructed using the experimental algorithm were interpreted separately and compared with interpretation of images obtained using the standard reconstruction technique. The experimental reconstruction algorithm improved spatial resolution, reduced streak artifacts, and yielded a better correlation with anatomic details of CT in comparison to conventional reconstruction methods ( e.g., filtered back-projection or OSEM with attenuation correction only). Images produced with the experimental algorithm produced a subjective improvement in the confidence of interpretation for 11 of 12 studies. There were also changes in interpretations for 4 of 12 studies although the changes were not sufficient to alter prognosis or the patient treatment plan.

A prospective comparison of acute intestinal toxicity following whole pelvic versus small field intensity-modulated radiotherapy for prostate cancer

Purpose

To compare the acute intestinal toxicity of whole pelvic (WP) and small field (SF) intensity-modulated radiotherapy (IMRT) for prostate cancer using dosimetric and metabolic parameters as well as clinical findings.

Methods

Patients who received IMRT in either a definitive or postoperative setting were prospectively enrolled. Target volume and organs at risk including intestinal cavity (IC) were delineated in every patient by a single physician. The IC volume that received a 10–50 Gy dose at 5-Gy intervals (V10–V50) and the percentage of irradiated volume as a fraction of total IC volume were calculated. Plasma citrulline levels, as an objective biological marker, were checked at three time points: baseline and after exposure to 30 Gy and 60 Gy.

Results

Of the 41 patients, only six experienced grade 1 acute intestinal toxicity. Although all dose–volume parameters were significantly worse following WP than SF IMRT, there was no statistically significant relationship between these dosimetric parameters and clinical symptoms. Plasma citrulline levels did not show a serial decrease by radiotherapy volume difference (WP versus SF) and were not relevant to the irradiated doses.

Conclusion

Given that WP had comparable acute intestinal toxicities to those associated with SF, WP IMRT appears to be a feasible approach for the treatment of prostate cancer despite dosimetric disadvantages.

Could machine learning improve the prediction of pelvic nodal status of prostate cancer patients? Preliminary results of a pilot study

We tested and compared performances of Roach formula, Partin tables and of three Machine Learning (ML) based algorithms based on decision trees in identifying N+ prostate cancer (PC). 1,555 cN0 and 50 cN+ PC were analyzed. Results were also verified on an independent population of 204 operated cN0 patients, with a known pN status (187 pN0, 17 pN1 patients). ML performed better, also when tested on the surgical population, with accuracy, specificity, and sensitivity ranging between 48-86%, 35-91%, and 17-79%, respectively. ML potentially allows better prediction of the nodal status of PC, potentially allowing a better tailoring of pelvic irradiation.

Toxicity of tomotherapy-based simultaneous integrated boost in whole-pelvis radiation for prostate cancer

PURPOSE

The validity of tomotherapy-based simultaneous integrated boost (TOMOSIB) was assessed in terms of acute intestinal/urinary toxicity by comparing with 3-dimensional conformal radiotherapy (3DCRT) in cases of whole-pelvis radiation therapy (WPRT) for prostate cancer.

MATERIALS AND METHODS

Thirty-eight consecutive patients who underwent curative WPRT were retrospectively reviewed. Twenty six (68.4%) received 3DCRT and the others (31.6%) were treated with TOMOSIB. A local boost to the prostate circumferential area was added to WPRT sequentially for 3DCRT and concomitantly for TOMOSIB. The total median prostate or prostatic bed dose was 64.8 Gy including median 45.0 Gy of WPRT. Acute toxicities were assessed according to RTOG criteria.

RESULTS

Overall intestinal toxicity was lower in TOMOSIB group than 3DCRT group (p=0.008). When it was divided into rectum and non-rectum intestine (NRI), TOMOSIB showed borderline superiority only in NRI toxicity (p=0.047). For the urinary toxicity, there was no significant difference between two groups (p=0.796). On dosimetric analysis for the rectum and bladder, dose delivered to 80% (p<0.001) and volume receiving 25-40 Gy (p<0.001) were remarkably higher in 3DCRT. For the NRI, only maximum dose showed significant results between two groups (p<0.001).

CONCLUSION

Intestinal toxicity should be verified with more detailed anatomic categorization such as rectum and NRI. TOMOSIB could not reduce urinary toxicity because of inevitably high dose exposure to the prostatic urethra. Current dosimetry system did not properly reflect intestinal/urinary toxicity, and suitable dosimetric guidelines are needed in TOMOSIB.

Offline multiple adaptive planning strategy for concurrent irradiation of the prostate and pelvic lymph nodes

PURPOSE

Concurrent irradiation of the prostate and pelvic lymph nodes (PLNs) can be challenging due to the independent motion of the two target volumes. To address this challenge, the authors have proposed a strategy referred to as Multiple Adaptive Planning (MAP). To minimize the number of MAP plans, the authors' previous work only considered the prostate motion in one major direction. After analyzing the pattern of the prostate motion, the authors investigated a practical number of intensity-modulated radiotherapy (IMRT) plans needed to accommodate the prostate motion in two major directions simultaneously.

METHODS

Six patients, who received concurrent irradiation of the prostate and PLNs, were selected for this study. Nine MAP-IMRT plans were created for each patient with nine prostate contours that represented the prostate at nine locations with respect to the PLNs, including the original prostate contour and eight contours shifted either 5 mm in a single anterior-posterior (A-P), or superior-inferior (S-I) direction, or 5 mm in both A-P and S-I directions simultaneously. From archived megavoltage cone beam CT (MV-CBCT) and a dual imaging registration, 17 MV-CBCTs from 33 available MV-CBCT from these patients showed large prostate displacements (>3 mm in any direction) with respect to the pelvic bones. For each of these 17 fractions, one of nine MAP-IMRT plans was retrospectively selected and applied to the MV-CBCT for dose calculation. For comparison, a simulated isocenter-shifting plan and a reoptimized plan were also created for each of these 17 fractions. The doses to 95% (D95) of the prostate and PLNs, and the doses to 5% (D5) of the rectum and bladder were calculated and analyzed.

RESULTS

For the prostate, D95 > 97% of the prescription dose was observed in 16, 16, and 17 of 17 fractions for the MAP, isocenter-shifted, and reoptimized plans, respectively. For PLNs, D95 > 97% of the prescription doses was observed in 10, 3, and 17 of 17 fractions for the three types of verification plans, respectively. The D5 (mean ± SD) of the rectum was 45.78 ± 5.75, 45.44 ± 4.64, and 44.64 ± 2.71 Gy, and the D5 (mean ± SD) of the bladder was 45.18 ± 2.70, 46.91 ± 3.04, and 45.67 ± 3.61 Gy for three types of verification plans, respectively.

CONCLUSIONS

The MAP strategy with nine IMRT plans to accommodate the prostate motions in two major directions achieved good dose coverage to the prostate and PLNs. The MAP approach can be immediately used in clinical practice without requiring extra hardware and software.

[Is there a role for pelvic lymphadenectomy before radiation therapy in localized prostate carcinoma?]

Pelvic nodal irradiation has classically been recommended in all patients with a predicted lymph node invasion risk of 15% or greater. However, in view of the results of recent series of extended lymphadenectomy, this rule has been critically discussed. Moreover, the technological progress of radiotherapy has drastically decreased the risk of rectal and urinary injuries secondary to the pelvic irradiation. These two points have lead the teams who used to perform a staging lymphadectomy before radiation therapy in order to avoid a useless pelvic irradiation to the N0 patients, to question this attitude. The objective of this review is to discuss these points and to present the clinical situations in which a pelvic lymphadenectomy performed before the irradiation of a prostate cancer, either exclusive or associated to an androgen deprivation, keeps a potential benefit.

[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.

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.

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.

Functional imaging for prostate cancer: therapeutic implications

Functional radionuclide imaging modalities, now commonly combined with anatomical imaging modalities computed tomography (CT) or magnetic resonance imaging (single photon emission computed tomography [SPECT]/CT, positron emission tomography [PET]/CT, and PET/magnetic resonance imaging), are promising tools for the management of prostate cancer, particularly for therapeutic implications. Sensitive detection capability of prostate cancer using these imaging modalities is one issue; however, the treatment of prostate cancer using the information that can be obtained from functional radionuclide imaging techniques is another challenging area. There are not many SPECT or PET radiotracers that can cover the full spectrum of the management of prostate cancer from initial detection to staging, prognosis predictor, and all the way to treatment response assessment. However, when used appropriately, the information from functional radionuclide imaging improves, and sometimes significantly changes, the whole course of the cancer management. The limitations of using SPECT and PET radiotracers with regard to therapeutic implications are not so much different from their limitations solely for the task of detecting prostate cancer; however, the specific imaging target and how this target is reliably imaged by SPECT and PET can potentially make significant impact in the treatment of prostate cancer. Finally, although the localized prostate cancer is considered manageable, there is still significant need for improvement in noninvasive imaging of metastatic prostate cancer, in treatment guidance, and in response assessment from functional imaging, including radionuclide-based techniques. In this review article, we present the rationale of using functional radionuclide imaging and the therapeutic implications for each of radionuclide imaging agent that have been studied in human subjects.

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.

Magnetic resonance lymphography-guided selective high-dose lymph node irradiation in prostate cancer

PURPOSE

To demonstrate the feasibility of magnetic resonance lymphography (MRL) -guided delineation of a boost volume and an elective target volume for pelvic lymph node irradiation in patients with prostate cancer. The feasibility of irradiating these volumes with a high-dose boost to the MRL-positive lymph nodes in conjunction with irradiation of the prostate using intensity-modulated radiotherapy (IMRT) was also investigated.

METHODS AND MATERIALS

In 4 prostate cancer patients with a high risk of lymph node involvement but no enlarged lymph nodes on CT and/or MRI, MRL detected pathological lymph nodes in the pelvis. These lymph nodes were identified and delineated on a radiotherapy planning CT to create a boost volume. Based on the location of the MRL-positive lymph nodes, the standard elective pelvic target volume was individualized. An IMRT plan with a simultaneous integrated boost (SIB) was created with dose prescriptions of 42 Gy to the pelvic target volume, a boost to 60 Gy to the MRL-positive lymph nodes, and 72 Gy to the prostate.

RESULTS

All MRL-positive lymph nodes could be identified on the planning CT. This information could be used to delineate a boost volume and to individualize the pelvic target volume for elective irradiation. IMRT planning delivered highly acceptable radiotherapy plans with regard to the prescribed dose levels and the dose to the organs at risk (OARs).

CONCLUSION

MRL can be used to select patients with limited lymph node involvement for pelvic radiotherapy. MRL-guided delineation of a boost volume and an elective pelvic target volume for selective high-dose lymph node irradiation with IMRT is feasible. Whether this approach will result in improved outcome for these patients needs to be investigated in further clinical studies.

Increased expression of elongation factor-1α is significantly correlated with poor prognosis of human prostate cancer

OBJECTIVE

Overexpression of elongation factor-1α (EF-1α) has been demonstrated to be related to increased cell proliferation, oncogenic transformation and delayed cell senescence. The purpose of this study was to determine whether EF-1α expression affects the progression of prostate cancer (PCa), and whether it can be used as a prognostic marker for PCa.

MATERIAL AND METHODS

EF-1α was evaluated by immunostaining in paraffin-embedded specimens of prostates obtained from 80 patients with PCa. Correlations of EF-1α with patients' ages, Gleason scores, American Joint Committee on Cancer (AJCC) stages, International Union Against Cancer (UICC) stages, preoperative prostate-specific antigen (PSA) concentrations and PSA failure were evaluated. Survival in all patients was analysed to evaluate the influence of EF-1α expression in cancer progression using Kaplan-Meier and multivariate Cox regression analysis.

RESULTS

The positive expression rate of EF-1α in PCa tissues [64/80 (80.0%)] was significantly higher than that in normal prostate tissues [1/20 (5.0%)] (p < 0.001). Increased immunostaining of EF-1α was a significant predictor of distant metastasis-free survival [hazard ratio (HR) 0.386, 95% confidence interval (CI) 0.032-2.519, p = 0.003] and overall survival (HR 0.305, 95% CI 0.091-0.872, p = 0.005). In multivariate analysis including competing biological variables, EF-1α expression was still significantly linked to distant metastasis-free survival (HR 0.216, 95% CI 0.042-0.876, p = 0.015) and overall survival (HR 0.395, 95% CI 0.116-0.798, p = 0.008).

CONCLUSION

These findings provide convincing evidence for the first time that EF-1α correlates closely with the survival of patients with PCa and may be a novel prognostic marker.

Benefit of whole pelvic radiotherapy combined with neoadjuvant androgen deprivation for the high-risk prostate cancer

AIM

To study whether use of neoadjuvant androgen deprivation therapy (N-ADT) combined with whole pelvic radiotherapy (WPRT) for high-risk prostate cancer patients was associated with survival benefit over prostate radiotherapy (PORT) only.

MATERIAL AND METHODS

Between 1999 and 2004, 162 high-risk prostate cancer patients were treated with radiotherapy combined with long-term androgen deprivation therapy (L-ADT). Patients were prospectively assigned into two groups: A (N-ADT + WPRT + L-ADT) n = 70 pts, B (PORT + L-ADT) n = 92 pts.

RESULTS

The 5-year actuarial overall survival (OS) rates were 89% for A and 78% for B (P = .13). The 5-year actuarial cause specific survival (CSS) rates were A = 90% and B = 79% (P = .01). Biochemical progression-free survival (bPFS) rates were 52% versus 40% (P = .07), for groups A and B, respectively.

CONCLUSIONS

The WPRT combined with N-ADT compared to PORT for high-risk patients resulted in improvement in CSS and bPFS; however no OS benefit was observed.

Variation in the definition of clinical target volumes for pelvic nodal conformal radiation therapy for prostate cancer

PURPOSE

We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group.

METHODS AND MATERIALS

Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition.

RESULTS

Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 +/- 203 for case 1 and 60.3, 627.7, 251.8 +/- 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire.

CONCLUSIONS

Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

Newer imaging modalities to assist with target localization in the radiation treatment of prostate cancer and possible lymph node metastases

Precise localization of prostate cancer and the drainage lymph nodes is mandatory to define an accurate clinical target volume for conformal radiotherapy. Better target definition and delineation on a daily basis is surely important in quality assurance for fractionated radiation therapy. This article reviews the evidence for major emerging techniques that show promise in better identifying the clinical target volume. Partial prostate boost by brachytherapy, intensity-modulated radiation therapy, or protons has become possible not only with standard imaging techniques but also with the availability of metabolic images obtained by magnetic resonance spectroscopy. Even though fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography has not been found to be useful, novel radiolabeled tracers may eventually prove of value in the diagnosis and treatment planning of prostate cancer. For the metastatic lymph nodes, lymphotropic nanoparticle-enhanced magnetic resonance imaging using ultra-small superparamagnetic iron oxide particles has greater accuracy as compared with conventional techniques and has been instrumental in delineating the lymphatic drainage of the prostate gland. These novel investigational techniques could further help in optimizing conformal radiotherapy for patients with prostate cancer. The concepts of biologic target volume, real target volume, and multidimensional conformal radiotherapy are being explored.

Pelvic lymph node irradiation for prostate cancer: who, why, and when?

Prostate cancers are best characterized by their clinical (TNM) stage, Gleason score, and serum prostate-specific antigen (PSA) level. These 3 factors are known to influence the risk of pelvic nodal involvement. By combining these prognostic factors, nomograms and equations have been developed and are widely used in clinical practice as an accurate way of predicting the probability of a given pathological stage. Patients who have a significant risk of pelvic nodal metastasis will likely have higher biochemical failure rates. Results from the multi-institutional prospective trials have shown that patients at an intermediate to high risk for pelvic nodal involvement experience disease progression-free survival benefits from the use of whole pelvic radiotherapy combined with hormone therapy. Yet, significant biological interactions between radiation treatment volumes and timing of hormone therapy have been shown. Further study of these issues is necessary to define the best treatment for patients at significant risk of pelvic lymph node involvement.

Is There a Role for Pelvic Irradiation in Localized Prostate Adenocarcinoma? Preliminary Results of GETUG-01

Purpose

To assess the benefit and toxicity and quality-of-life (QOL) outcomes of pelvic nodes irradiation in nonmetastatic prostate carcinoma patients.

Patients and Methods

Between December 1998 and June 2004, 444 patients with T1b-T3, N0 pNx, M0 prostate carcinoma were randomly assigned to either pelvic and prostate radiotherapy or prostate radiotherapy only. Patients were stratified according to the prognostic factor of lymph node involvement (LNI). Short-term 6-month neoadjuvant and concomitant hormonal therapy was allowed only for patients in the high-risk group. The pelvic dose was 46 Gy. The total dose recommended to the prostate was changed during the course of the study from 66 Gy to 70 Gy. Criteria for progression-free survival (PFS) included biologic prostate-specific antigen recurrences or a local or metastatic evolution. Acute and late toxicities were recorded according to the Radiation Therapy Oncology Group and Late Effects in Normal Tissues Subjective, Objective, Management, and Analytic scales, respectively. The QOL outcome was recorded with the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30, the International Prostatic Symptom Score, and the Sexual Function Index scales.

Results

With a 42.1-month median follow-up time, the 5-year PFS and overall survival were similar in the two treatment arms for the whole series and for each stratified group. On multivariate analysis, low LNI risk and hormonal therapy were statistically associated with increased PFS. However, subgroup analyses based on these factors did not show any benefit for pelvic irradiation. There were no significant differences in acute and late digestive toxicities and in QOL outcomes.

Conclusion

Pelvic node irradiation was well tolerated but did not improve PFS.

Prostate Cancer-Specific Survival and Clinical Progression-Free Survival in Men with Prostate Cancer Treated Intermittently with Testosterone Inactivating Pharmaceuticals

OBJECTIVES

More than 85% of men with prostate cancer die of other causes. An effective method is needed to distinguish fatal forms of prostate cancer from benign variants.

METHODS

We performed a retrospective chart review from a medical oncology practice specializing in prostate cancer. All men with negative bone scans, prostate-specific antigen (PSA) level less than 100 ng/mL, adequate records for review, and who started taking testosterone inactivating pharmaceutical (TIP) agents before January 2000 were included in the study. Six factors were evaluated as potential predictors of prostate cancer-specific mortality: PSA nadir greater than 0.05 ng/mL while taking TIP, PSA doubling time of less than 12 months, Gleason score, stage, baseline PSA level greater than 20 ng/mL, and age.

RESULTS

The study criteria were met by 160 men. The median follow-up was 10 years. The median age, PSA level, PSA nadir, and PSA doubling time was 65.6 years, 9.6 ng/mL, 0.03 ng/mL, and 10 months, respectively. Of the 160 men, 39 died of prostate cancer. Death from prostate cancer was far more common (78% versus 11%) and accelerated (median of 4 years versus 7 years) for men with a PSA nadir greater than 0.05 ng/mL than for those with a lower nadir. Multivariate Cox regression analysis indicated that the hazard ratio for prostate cancer-specific mortality in men with a PSA nadir greater than 0.05 ng/mL was 11.6 (P <0.0001). The hazard ratio for men with a PSA doubling time of less than 12 months was 2.9 (P = 0.04). Gleason score, stage, baseline PSA level greater than 20 ng/mL, and age were not statistically significant.

CONCLUSIONS

Of the factors studied, the PSA nadir while taking a TIP was the best predictor of prostate cancer-specific mortality.

Evidence-based radiation oncology: Definitive, adjuvant and salvage radiotherapy for non-metastatic prostate cancer

The standard treatment options based on the risk category (stage, Gleason score, PSA) for localized prostate cancer include surgery, radiotherapy and watchful waiting. The literature does not provide clear-cut evidence for the superiority of surgery over radiotherapy, whereas both approaches differ in their side effects. The definitive external beam irradiation is frequently employed in stage T1b-T1c, T2 and T3 tumors. There is a pretty strong evidence that intermediate- and high-risk patients benefit from dose escalation. The latter requires reduction of the irradiated normal tissue (using 3-dimensional conformal approach, intensity modulated radiotherapy, image-guided radiotherapy, etc.). Recent data suggest that prostate cancer may benefit from hypofractionation due to relatively low alpha/beta ratio; these findings warrant confirmation though. The role of whole pelvis irradiation is still controversial. Numerous randomized trials demonstrated a clinical benefit in terms of biochemical control, local and distant control, and overall survival from the addition of androgen suppression to external beam radiotherapy in intermediate- and high-risk patients. These studies typically included locally advanced (T3-T4) and poor-prognosis (Gleason score >7 and/or PSA >20 ng/mL) tumors and employed neoadjuvant/concomitant/adjuvant androgen suppression rather than only adjuvant setting. The ongoing trials will hopefully further define the role of endocrine treatment in more favorable risk patients and in the setting of the dose escalated radiotherapy. Brachytherapy (BRT) with permanent implants may be offered to low-risk patients (cT1-T2a, Gleason score <7, or 3+4, PSA <or=10 ng/mL), with prostate volume of <or=50 ml, no previous transurethral prostate resection and a good urinary function. Some recent data suggest a benefit from combining external beam irradiation and BRT for intermediate-risk patients. EBRT after radical prostatectomy improves disease-free survival and biochemical and local control rates in patients with positive surgical margins or pT3 tumors. Salvage radiotherapy may be considered at the time of biochemical failure in previously non-irradiated patients.

Radiation therapy in prostate cancer

Adenocarcinoma of the prostate is one of the most frequently diagnosed cancers of men in the Western hemisphere and is second only to lung cancer for male cancer mortality. Most patients are diagnosed in the early/clinically localized stage, which can be treated curatively with radiation therapy alone. Innovative methods such as brachytherapy, three-dimensional conformal radiotherapy (3D-CRT), and IMRT (intensity modulated radiotherapy) are able to deliver very high tumoricidal doses to the diseased prostate, with minimal side effects to the surrounding tissue. Radiation therapy combined with hormonal treatment can be curative in locally advanced disease. Radiation therapy is also very effective in alleviating symptoms of metastatic prostate cancer (bone metastases, spinal cord compression, and bladder outlet obstruction).

Radiotherapy after prostatectomy: improved biochemical relapse-free survival with whole pelvic compared with prostate bed only for high-risk patients

PURPOSE

To compare the biochemical relapse-free survival (bRFS) among patients receiving whole pelvic radiotherapy (WPRT) vs. prostate bed RT (PBRT) after radical prostatectomy.

METHODS AND MATERIALS

Between 1985 and 2005, 160 patients underwent adjuvant or salvage RT after radical prostatectomy. A short course of total androgen suppression was also given concurrently to 87 patients. Of the 160 patients, 114 were considered at high risk of lymph node involvement because they had a pathologic Gleason score of >/=8, a preoperative prostate-specific antigen level >20 ng/mL, seminal vesicle or prostate capsule involvement, or pathologic lymph node involvement. Of this group, 72 underwent WPRT and 42 underwent PBRT. The median follow-up was >5 years for all patient subsets. Kaplan-Meier and Cox proportional hazards multivariate analyses were performed for all clinical, pathologic, and treatment factors predicting for bRFS.

RESULTS

Whole pelvic RT resulted in superior bRFS compared with PBRT (p = 0.03). The advantage of WPRT was limited to high-risk patients, with a 5-year bRFS rate of 47% (95% confidence interval, 35-59%) after WPRT vs. 21% (95% confidence interval, 8-35%) after PBRT (p = 0.008). For low-risk patients, no difference (p = 0.9) was found. On multivariate analysis, only WPRT (p = 0.02) and a preoperative prostate-specific antigen level <1.0 ng/mL (p = 0.002) were significantly associated with bRFS. The benefit from total androgen suppression with postoperative RT was only observed when given concurrently with WPRT (p = 0.04) and not with PBRT (p = 0.4).

CONCLUSION

The results of our study have indicated that WPRT confers superior bRFS compared with PBRT for high-risk patients receiving adjuvant or salvage RT after radical prostatectomy. This advantage was observed only with concurrent TAS. These results are analogous to the benefit from WPRT seen in the Radiation Therapy Oncology Group 94-13 study.

State-of-the-art radiotherapy in the management of clinically localized prostate carcinoma

Four Phase III trials demonstrating higher prostate-specific antigen control rates in prostate cancer patients treated with higher doses of radiation have changed the standard of care. Emerging on-line technologies, improved imaging and computer algorithms, combined with an improved understanding of how best to apply them, have allowed radiation oncologists to move ever closer to the optimal application of curative radiation. This technology allows a higher dose to be delivered to tumor-bearing areas while minimizing the dose delivered to surrounding normal tissues. Real-time adaptive techniques have made each step more accurate, and commercialization has increasingly moved these advances further into the community setting. Phase III trials have also helped to define the role of hormonal therapy in combination with radiation and the benefits of prophylactic pelvic nodal radiotherapy in subsets of patients. We have also learnt how to optimize the use of prostate-specific antigen to better determine success and failure following radiotherapy.

Optimized coverage of high-risk adjuvant lymph node areas in prostate cancer using a sentinel node–based, intensity-modulated radiation therapy technique

PURPOSE

Irradiation of adjuvant lymph nodes in high-risk prostate cancer was shown to be associated with improved rates of biochemical nonevidence of disease in the Radiation Therapy Oncology Group trial (RTOG 94-13). To account for the highly individual lymphatic drainage pattern we tested an intensity-modulated radiation therapy (IMRT) approach based on the determination of pelvic sentinel lymph nodes (SN).

METHODS AND MATERIALS

Patients with a risk of more than 15% lymph node involvement were included. For treatment planning, SN localizations were included into the pelvic clinical target volume. Dose prescriptions were 50.4 Gy to the adjuvant area and 70.0 Gy to the prostate. All treatment plans were generated using equivalent uniform dose (EUD)-based optimization algorithms and Monte Carlo dose calculations and compared with 3D conventional plans.

RESULTS

A total of 25 patients were treated and 142 SN were detectable (mean: n = 5.7; range, 0-13). Most SN were found in the external iliac (35%), the internal iliac (18.3%), and the iliac commune (11.3%) regions. Using a standard CT-based planning target volume, relevant SN would have been missed in 19 of 25 patients, mostly in the presacral/perirectal area (22 SN in 12 patients). The comparison of conventional 3D plans with the respective IMRT plans revealed a clear superiority of the IMRT plans. No gastrointestinal or genitourinary acute toxicity Grade 3 or 4 (RTOG criteria) occurred.

CONCLUSIONS

Distributions of SN are highly variable. Data for SN derived from single photon emission computed tomography are easily integrated into an IMRT-based treatment strategy. By using SN data the probability of a geographic miss is reduced. The use of IMRT allows sparing of normal tissue irradiation.

Management of Locally Advanced Prostate Cancer: Past, Present, Future

PURPOSE

Historically advanced prostate cancer had been treated with androgen ablation. With the evolution of radiation therapy it was shown that some patients with advanced but nonmetastatic disease could be cured or at least have progression delayed. Subsequently a series of studies demonstrated that the combination of radiation and androgen ablation resulted in improved results over those of radiation therapy alone, although the failure rate was still high. This review explores the continued evolution in the treatment of high risk disease.

MATERIALS AND METHODS

The published literature on treatment for high risk prostate cancer was reviewed.

RESULTS

Adding androgen ablation to radiation decreased the failure rate from 79% to 67% in older studies and 55% to 25% in more recent studies. Most contemporary studies of higher radiation doses showed further improvement with a failure rate of 20% to 40%. The results of adding an implant boost appears to have decreased the failure rate further to 30% or less in most studies. There is now great interest in exploring chemotherapy or biological agents as adjuvant therapy to try to improve the results further. The role of surgery in these patients is also awaiting further clarification.

CONCLUSIONS

Radiation therapy has been the primary mode of curative therapy for high risk prostate cancer for 3 decades. Much progress has been made. Evolving data suggest that radiation will continue to have the primary role in treatment in these patients in the future.

Radiothérapie conformationnelle du cancer de la prostate : technique et résultats

A number of retrospective and prospective studies have demonstrated that radiotherapy of prostate cancer must be actually conformal. Three-dimensional (3D) treatment planning consists in an as accurate as possible definition of target-volume, usually by CT-scan, and design of radiation fields shaped to this target-volume. Several steps are required, each step being important for the overall quality of the treatment. Conformal radiotherapy is better tolerated than conventional irradiation, with significantly less rectal toxicity. It allows dose-escalation up to 80 Gy. It is now possible to go beyond this dose with intensity-modulated radiotherapy. The benefit of these high doses was demonstrated by some large retrospective studies and some prospective dose-escalation trials. Several randomized trials are in progress, preliminary results of two of them have been published, both showing an improvement in disease control with the higher doses. The advantage of higher doses is clearly evident for patients in the intermediate prognostic group, but is still discussed for patients with a low risk tumour or treated in combination with hormone therapy. Late proctitis is the main toxicity of these high doses. Some volume constraints have been defined during the last years and will allow a decrease of the rate of rectal toxicity. Because of these technological improvements, results of radiation therapy are now similar to those of surgery: no direct comparison with a randomized trial is available, but large comparative studies show that long-term disease control are identical with both techniques. Radiation therapy must be proposed to all patients with a prostate carcinoma as an alternative to surgery.

Distribution of lymph nodes in men with prostatic adenocarcinoma and lymphadenopathy at presentation: a retrospective radiological review and implications for prostate and pelvis radiotherapy

AIMS

To describe the distribution of enlarged lymph nodes by nodal group found radiologically in patients presenting with adenocarcinoma of the prostate. This will help to define which nodal groups should be treated during the pelvic radiotherapy of patients with less advanced disease.

MATERIALS AND METHODS

The scans of 55 men presenting with prostate cancer and metastases to lymph nodes only were reviewed. Lymph nodes of 8 mm or more in size were considered to be enlarged.

RESULTS

The medial external iliac (obturator) nodes were most commonly enlarged (75% of patients) followed by nodes in the para-aortic region (26%) and anterior internal iliac region (24%). Para-aortic lymph-node enlargement was uncommon in the absence of pelvic lymphadenopathy. Midline pre-sacral lymph-node enlargement was not observed. Incidence of enlarged lymph nodes in the lateral external iliac group was 18%, an area which may not be routinely included during radiotherapy.

CONCLUSION

There is a case for studying further the role of including lateral external iliac lymph nodes in the pelvic radiotherapy volume, as there may be an appreciable risk of lymph-node spread to this area.

The role of whole pelvic radiotherapy in locally advanced prostate cancer

Routine PSA testing has led to diagnosis and treatment of prostate cancer at earlier stages than previously. Earlier and technically-improved treatment, together with escalation of dose has enhanced cure rates. Although, the incidence of nodal metastases is now lower than in pre-PSA days, more extended pelvic lymphadenectomies have shown the actual rate of lymph node involvement to be higher than had been determined from standard radical prostate surgery. As in cancers in other sites, especially in their earlier stages, lymph node metastases may exist in the absence of haematogenous dissemination. This, together with the improved rates of control of the primary prostate tumour, suggests that elective irradiation of early-stage lymph nodes from prostate cancer should enhance survival in a manner analogous to improvements seen with this approach in other cancers. Although, the absolute incidence of positive nodes in locally advanced prostate cancer warrants elective radiotherapy, it is relatively low and the modest improvements to be expected may be undetected in the results of a small trial.

Comparison of treatment volumes and techniques in prostate cancer radiation therapy

OBJECTIVE

To compare dose-volume histograms (DVHs) for 3 target volumes (group 1, prostate + seminal vesicles + pelvic lymph nodes; group 2, prostate + seminal vesicles; group 3, prostate only) to determine the difference in dose to normal structures (rectum, bladder, and femoral heads) while controlling for target dose using 3-dimensional conformal radiation therapy (3DCRT) versus intensity modulated radiation therapy (IMRT).

METHODS

Ten patients with localized prostate cancer were randomly selected. 3DCRT and IMRT planning were done to deliver 75.6 Gy to the prostate, 50.4 Gy to the pelvic nodes, and 55.8 Gy to the seminal vesicles at a standard fractionation of 1.8 Gy. An additional plan delivering 75.6 Gy to the seminal vesicles using IMRT was run. DVHs were compared for 3DCRT and IMRT.

RESULTS

In all 3 groups, the percent rectum receiving > or =70 Gy, > or =60 Gy, and > or =40 Gy was significantly less for IMRT than for 3DCRT. Increasing target volumes, as necessary for pelvic nodal irradiation, overall did not result in higher rectal doses for IMRT. With 3DCRT, however, larger target volumes did increase the amount of rectum irradiated. Similar results were obtained for the femoral heads whereas results for the bladder were mixed.

CONCLUSION

When compared with 3DCRT, IMRT delivered equivalent or higher doses to the target volume with greater sparing of critical organs. Because dose-volume parameters have been shown to relate to toxicity, IMRT would appear to be the favored technique for prostate cancer radiation, particularly with regard to nodal treatment.

Treatment options in lymph node-positive prostate cancer

With improved awareness and screening, the incidence of lymph node-positive prostate cancer has declined dramatically over the last 50 years. Stage of cancer, prostate-specific antigen, and grade are risk factors for positive lymph nodes; and those factors, along with the number of involved lymph nodes, are prognostic factors for outcome. Although the numbers have declined, the number of men with lymph node-positive prostate cancer remains significant, and the current challenge is how best to treat these patients. Commonly used treatments include any combination of androgen ablation, surgery, and radiation. There have been a few studies with chemotherapy, and no treatment has been proven superior to the others. Consequently, there remain several reasonable alternatives to treatment, and long-term survival is not unusual.