Prostate cancer radiation dose response: results of the M. D. Anderson phase III randomized trial

Investigation of bladder dose and volume factors influencing late urinary toxicity after external beam radiotherapy for prostate cancer

BACKGROUND

We sought to identify the bladder dose-volume factors associated with an increased risk of late urinary toxicity among prostate cancer patients treated with radiotherapy.

METHODS AND MATERIALS

This retrospective analysis included data from 128 prostate cancer patients treated on protocol with 2 Gy/fraction to 46 Gy followed by a boost to 78 Gy. The endpoint for this analysis was Grade 1 or greater late genitourinary (GU) toxicity occurring within two years of treatment. The Lyman-Kutcher-Burman, mean dose, threshold dose, and hottest volume models were fitted to the toxicity data using the maximum likelihood method.

RESULTS

Model fits based on dose-volume histograms tended to fit the toxicity data better than models based on dose-wall histograms. The hottest volume (hotspot) model was found to be the best-fitting model investigated. The best fit was for the hottest 2.9% of bladder (95% CI, 1.1-6.8%). This model has an area under the receiver operating characteristic curve of 0.74. The hotspot model separated the patients into clinically meaningful subgroups with approximately 25% of the patients who received <78 Gy to the hottest 2.9% of bladder had GU toxicity at eight years compared with approximately 50% when the dose was > or =78 Gy (p = 0.002).

CONCLUSION

This provides the first evidence supporting that bladder "hotspots" are related to GU toxicity within two years after external beam radiotherapy for prostate cancer. Confirming data are needed from other investigators. Particular attention should be given to hotspots higher than 78 Gy in bladder in radiation treatment planning.

Androgen induces adaptation to oxidative stress in prostate cancer: implications for treatment with radiation therapy

Radiation therapy is a standard treatment for prostate cancer (PC). The postulated mechanism of action for radiation therapy is the generation of reactive oxygen species (ROS). Adjuvant androgen deprivation (AD) therapy has been shown to confer a survival advantage over radiation alone in high-risk localized PC. However, the mechanism of this interaction is unclear. We hypothesize that androgens modify the radioresponsiveness of PC through the regulation of cellular oxidative homeostasis. Using androgen receptor (AR)(+) 22rv1 and AR(-) PC3 human PC cell lines, we demonstrated that testosterone increased basal reactive oxygen species (bROS) levels, resulting in dose-dependent activation of phospho-p38 and pAKT, and increased expression of clusterin, catalase, and manganese superoxide dismutase. Similar data were obtained in three human PC xenografts; WISH-PC14, WISH-PC23, and CWR22, growing in testosterone-supplemented or castrated SCID mice. These effects were reversible through AD or through incubation with a reducing agent. Moreover, testosterone increased the activity of catalase, superoxide dismutases, and glutathione reductase. Consequently, AD significantly facilitated the response of AR(+) cells to oxidative stress challenge. Thus, testosterone induces a preset cellular adaptation to radiation through the generation of elevated bROS, which is modified by AD. These findings provide a rational for combined hormonal and radiation therapy for localized PC.

The predictive value of 2-year posttreatment biopsy after prostate cancer radiotherapy for eventual biochemical outcome

PURPOSE

To determine the value of a 2-year post-radiotherapy (RT) prostate biopsy for predicting eventual biochemical failure in patients who were treated for localized prostate cancer.

METHODS AND MATERIALS

This study comprised 164 patients who underwent a planned 2-year post-RT prostate biopsy. The independent prognostic value of the biopsy results for forecasting eventual biochemical outcome and overall survival was tested with other factors (the Gleason score, 1992 American Joint Committee on Cancer tumor stage, pretreatment prostate-specific antigen level, risk group, and RT dose) in a multivariate analysis. The current nadir + 2 (CN + 2) definition of biochemical failure was used. Patients with rising prostate-specific antigen (PSA) or suspicious digital rectal examination before the biopsy were excluded.

RESULTS

The biopsy results were normal in 78 patients, scant atypical and malignant cells in 30, carcinoma with treatment effect in 43, and carcinoma without treatment effect in 13. Using the CN + 2 definition, we found a significant association between biopsy results and eventual biochemical failure. We also found that the biopsy status provides predictive information independent of the PSA status at the time of biopsy.

CONCLUSION

A 2-year post-RT prostate biopsy may be useful for forecasting CN + 2 biochemical failure. Posttreatment prostate biopsy may be useful for identifying patients for aggressive salvage therapy.

Differences and commonalities in the management of locally advanced prostate cancer: results from a survey of oncologists and urologists in the UK

OBJECTIVE

To determine the management practices used by UK oncologists and urologists for patients with locally advanced (non-metastatic) prostate cancer.

METHODS

Using a postal questionnaire, 155 practising specialist oncologists and urologists were surveyed in the UK. Their views were sought on a multidisciplinary approach to the management of locally advanced prostate cancer and their current management practices.

RESULTS

Over half of respondents recognized the need for both oncologists and urologists to take the lead in management decisions, but almost as many still expected the sole responsibility to lie within their own speciality. Radical radiotherapy (RT) was considered the current optimum treatment by most respondents, but 22% of urologists thought that radical prostatectomy is optimal. Most responders would use luteinizing hormone-releasing hormone agonists as neoadjuvant and adjuvant to RT but there was significant variation in the favoured duration of treatment of these drugs, and in the dose of RT.

CONCLUSION

This survey suggests that there are still wide variations in the management practices for locally advanced prostate cancer in the UK, and between urologists and oncologists. Improved consensus guidelines are required.

X-ray–assisted positioning of patients treated by conformal arc radiotherapy for prostate cancer: Comparison of setup accuracy using implanted markers versus bony structures

PURPOSE

The aim of this study was to compare setup accuracy of NovalisBody stereoscopic X-ray positioning using implanted markers in the prostate vs. bony structures in patients treated with dynamic conformal arc radiotherapy for prostate cancer.

METHODS AND MATERIALS

Random and systematic setup errors (RE and SE) of the isocenter with regard to the center of gravity of three fiducial markers were measured by means of orthogonal verification films in 120 treatment sessions in 12 patients. Positioning was performed using NovalisBody semiautomated marker fusion. The results were compared with a control group of 261 measurements in 15 patients who were positioned with NovalisBody automated bone fusion. In addition, interfraction and intrafraction prostate motion was registered in the patients with implanted markers.

RESULTS

Marker-based X-ray positioning resulted in a reduction of RE as well as SE in the anteroposterior, craniocaudal, and left-right directions compared with those in the control group. The interfraction prostate displacements with regard to the bony pelvis that could be avoided by marker positioning ranged between 1.6 and 2.8 mm for RE and between 1.3 and 4.3 mm for SE. Intrafraction random and systematic prostate movements ranged between 1.4 and 2.4 mm and between 0.8 and 1.3 mm, respectively.

CONCLUSION

The problem of interfraction prostate motion can be solved by using implanted markers. In addition, the NovalisBody X-ray system performs more accurately with markers compared with bone fusion. Intrafraction organ motion has become the limiting factor for margin reduction around the clinical target volume.

Using a priori structural information from magnetic resonance imaging to investigate the feasibility of prostate diffuse optical tomography and spectroscopy: a simulation study

Implementation of diffuse optical tomography (DOT) for prostate cancer is challenging because the prostate is a deep-seated organ. We investigated whether diffuse optical tomography (DOT) and spectroscopy could be applied to monitor the physiology of prostate cancer using a small probe that could be placed endorectally. We manually segmented the prostate, the intraprostatic tumor, and the rectum using data from endorectal magnetic resonance imaging. These structures were reconstructed and meshed with tetrahedral finite elements in three dimensions. A 2 x 4 cm probe that has ten sources and 52 detectors were placed to face the anterior wall of the rectum in our simulation. Optical properties of the organs were obtained from the literature in the near infrared regime. Diffusion approximation was used to simulate photon migration with finite element method. Five wavelengths were used to simulate tissue absorption with realistic water, oxy- and deoxyhaemoglobin concentrations in the prostate. We combined a global search based on genetic algorithm with gradient-driven local search methods to fit the simulated data. Our results suggest that the optical properties and the concentrations of the chromophores of the prostate and the prostate cancer can be reliably recovered from the measurements using an endorectal probe. Prostate DOT is worth further investigation for clinical application.

Percutaneous radiotherapy for low-risk prostate cancer: options for 2007

Technical developments of radiotherapy (RT) over the recent years yielded in better conformation to the target volume thus increasing the therapeutic ratio and decreasing side effects. This paper discusses these options for low-risk prostate cancer. There has been evidence from randomized trials, that for low-risk PCA doses >70 Gy are significant better in case of biochemical disease-free survival (bNED). Image-guided radiotherapy (IGRT) has been proven in several studies for reduced safety margins around the prostate target volume. Intensity-modulated radiotherapy (IMRT) allow treatment with higher doses and 5-year results are reported from several studies. Data from several randomized trials about adjuvant RT after radical prostatectomy (RP) have been reported. In two phase-III trials a significant advantage of 20% bNED was demonstrated for doses between 76 and 79 Gy compared with 70 Gy. Using IGRT, the safety margin around the prostate can be reduced for about 30-50%. Doses of >80 Gy can be given safely to the prostate with IMRT and <5% grade-III/IV late side effects. Adjuvant RT for positive margins after RP has been of proven advantage. Three phase-III trials achieved a significant better bNED of 20% for 5 years. The effect of doses >70 Gy have been proven for low-risk PCA. IGRT resulted in reduced safety margins and a decrease of acute and late side effects. The addition of IMRT allowed higher doses to the prostate. Adjuvant RT after RP for positive margins achieved a significant better bNED.

An adaptive off-line procedure for radiotherapy of prostate cancer

PURPOSE

To determine the planning target volume (PTV) margin for an adaptive radiotherapy procedure that uses five computed tomography (CT) scans to calculate an average prostate position and rectum shape. To evaluate alternative methods to determine an average rectum based on a single delineation.

METHODS AND MATERIALS

Repeat CT scans (8-13) of 19 patients were used. The contoured prostates of the first four scans were matched on the planning CT (pCT) prostate contours. With the resulting translations and rotations the average prostate position was determined. An average rectum was obtained by either averaging the coordinates of corresponding points on the rectal walls or by selecting the "best" rectum or transforming the pCT rectum. Dose distributions were calculated for various expanded average prostates. The remaining CT scans were used to determine the dose received by prostate and rectum during treatment.

RESULTS

For the prostate of the pCT scan and a 10-mm margin, all patients received more than 95% of the prescribed dose to 95% of the prostate. For the average prostate, a margin of 7 mm was needed to obtain a similar result (average PTV reduction 30%). The average rectum overestimated the mean dose to the rectum by 0.4 +/- 1.6 Gy, which was better than the pCT rectum (2.1 +/- 3.0 Gy) and the alternative average rectums (1.0 +/- 2.6 Gy and 1.4 +/- 3.2 Gy).

CONCLUSIONS

Our adaptive procedure allows for reduction of the PTV margin to 7 mm without decreasing prostate coverage during treatment. For accurate estimation of the rectum dose, rectums need to be delineated and averaged over multiple scans.

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.

Phase II study of neoadjuvant androgen deprivation followed by external-beam radiotherapy with 9 months of androgen deprivation for intermediate- to high-risk localized prostate cancer

PURPOSE

To evaluate the toxicity and efficacy of individualized neoadjuvant androgen deprivation (AD) to maximal response followed by external beam radiotherapy (RT) with continued AD for a total of 9 months in a prospective phase II trial.

PATIENTS AND METHODS

One hundred twenty-three patients received a total of 9 months of flutamide and luprolide combined with RT. RT initiation was individualized to begin after maximum response to AD as assessed by monthly digital rectal examination and prostate-specific antigen (PSA). The neoadjuvant phase was restricted to no more than 6 months.

RESULTS

Median time to initiation of RT was 4.7 months. Indications to begin RT (and their rates) were undetectable PSA (28%), PSA unchanged from one month to the next (46%), PSA rising from one month to the next (10%), 6 months of AD (14%), and other (2%). Five-year outcomes were biochemical disease-free survival, (DFS) 63% +/- 7%; clinical DFS, 75% +/- 5%; cancer-specific survival, 99% +/- 1%; and overall survival, 89% +/- 3%. Patients initiating RT after 6 months of AD had significantly lower biochemical and clinical DFS. Those patients whose testosterone recovered to normal after completion of AD had a significantly superior survival rate. Of those patients potent before treatment, 65% remained so at last follow-up.

CONCLUSION

The combination of 9 months of AD and RT, with initiation of RT individualized on the basis of maximum response to AD, achieves disease control rates comparable with past studies, while preserving potency in many patients. Further studies are warranted to determine the optimal combination of AD and RT in this patient population.

Results of radiation therapy combined with neoadjuvant hormonal therapy for stage III prostate cancer: comparison of two different definitions of PSA failure

BACKGROUND

We herein report the clinical outcome of radical radiation therapy combined with neoadjuvant hormonal therapy (NHT) for stage III (International Union Against Cancer [UICC] 1997: UICC 97) prostate cancer. Prostate-specific antigen (PSA) failure-free survival was assessed according to two different definitions, and the appropriateness of each definition is discussed.

METHODS

Between October 1997 and December 2000, 27 patients with stage III prostate cancer were enrolled in this study. The median pretreatment PSA level was 29 ng/ml (range, 7.4-430 ng/ml). The Gleason score (GS) was 7 or more in 22 patients (81%). All patients received 3 months of NHT with a luteinizing hormone-releasing hormone (LH-RH) analogue, in combination with an antiandrogen (flutamide), given during the first 2 weeks, followed by 70-Gy external-beam radiation therapy (EBRT) in 35 fractions. The initial 46 Gy was given with a four-field technique, while the remainder was given with a dynamic conformal technique. No adjuvant hormonal therapy (AHT) was given.

RESULTS

The median follow-up time was 63 months. PSA levels decreased to the normal range (<4 ng/ml) after irradiation in all but one patient. The 5-year PSA failure-free survival was 34.8% according to the American Society for Therapeutic Radiology and Oncology (ASTRO) definition and it was 43.0% according to the "nadir plus 2" definition. Discordance of the results between the two definitions was seen in two patients. The 5-year overall and cause-specific survivals were 83.0% and 93.3%, respectively. No severe acute or late adverse effects were observed.

CONCLUSION

Seventy Gy of EBRT following 3 months of NHT produced therapeutic results comparable to those reported in other studies which used long-term AHT. The value of long-term AHT for Japanese men should be tested in a clinical trial.

Predictors for rectal and intestinal acute toxicities during prostate cancer high-dose 3D-CRT: results of a prospective multicenter study

PURPOSE

To find predictors for rectal and intestinal acute toxicity in patients with prostate cancer treated with > or =70 Gy conformal radiotherapy.

METHODS AND MATERIALS

Between July 2002 and March 2004, 1,132 patients were entered into a cooperative study (AIROPROS01-02). Toxicity was scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale and by considering the changes (before and after treatment) of the scores of a self-administered questionnaire on rectal/intestinal toxicity. The correlation with a number of parameters was assessed by univariate and multivariate analyses. Concerning the questionnaire, only moderate/severe complications were considered.

RESULTS

Of 1,132 patients, 1,123 were evaluable. Of these patients, 375, 265, and 28 had Grade 1, 2, and 3 Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity, respectively. The mean rectal dose was the most predictive parameter (p = 0.0004; odds ratio, 1.035) for Grade 2 or worse toxicity, and the use of anticoagulants/antiaggregants (p = 0.02; odds ratio, 0.63) and hormonal therapy (p = 0.04, odds ratio, 0.65) were protective. The questionnaire-based scoring revealed that a greater mean rectal dose was associated with a greater risk of bleeding; larger irradiated volumes were associated with frequency, tenesmus, incontinence, and bleeding; hormonal therapy was protective against frequency and tenesmus; hemorrhoids were associated with a greater risk of tenesmus and bleeding; and diabetes associated highly with diarrhea.

CONCLUSION

The mean rectal dose correlated with acute rectal/intestinal toxicity in three-dimensional conformal radiotherapy for prostate cancer, and hormonal therapy and the use of anticoagulants/antiaggregants were protective. According to the moderate/severe injury scores on the self-assessed questionnaire, several clinical and dose-volume parameters were independently predictive for particular symptoms.

Impact of disseminated tumor cells in bone marrow at diagnosis in patients with nonmetastatic prostate cancer treated by definitive radiotherapy

The purpose of this study was to explore whether detection of disseminated tumor cells (DTCs) in bone marrow (BM) of nonmetastatic prostate cancer (PC) was associated with other clinical or histopathological factors at diagnoses or clinical outcome subsequent to definitive radiotherapy (RT). We evaluated BM aspirates from 272 cT(1-4)pN(0)M(0) PC patients by immunocytochemistry employing anticytokeratin antibodies (AE1/AE3). BM-status was compared with clinical and histopathological parameters. Long-term clinical outcome was assessed in 131 of the patients who all had completed definitive RT with or without androgen deprivation (AD), initiating treatment >5 years before cut-off date June 1, 2005. They had at least 1 unfavorable prognostic feature defined as cT(3-4) or Gleason score (GS) >or= 7B or PSA >or= 10 microg/l. Overall death, cause-specific death, distant metastases (DM) as first clinical relapse, local failure as first clinical relapse and biochemical failure were defined as end-points. DTCs were detected in 18% of the patients and were associated with increasing GS (p = 0.04) and percentage of Gleason pattern 4/5 (p = 0.04). The 7-year cumulative risk of DM was 21% for BM-positive patients vs. 6% for BM-negative patients (p = 0.07). In patients receiving RT without AD (n = 75), the 7-year cumulative risk of DM for BM-positive patients was 28% vs. 9% for BM-negative patients (p = 0.03). BM-status did not have impact on other end-points. In conclusion our study shows that presence of DTCs in BM at diagnosis was associated with the histological differentiation of the primary tumor and an increased risk of developing distant metastases after RT.

Intensity modulated radiotherapy for localized prostate cancer: rigid compliance to dose-volume constraints as a warranty of acceptable toxicity?

BACKGROUND

To report the toxicity after intensity modulated radiotherapy (IMRT) for patients with localized prostate cancer, as a sole treatment or after radical prostatectomy.

METHODS

Between August 2001 and December 2003, 132 patients with prostate cancer were treated with IMRT and 125 were evaluable to acute and late toxicity analysis, after a minimum follow-up time of one year. Clinical and treatment data, including normal tissue dose-volume histogram (DVH) constraints, were reviewed. Gastro-intestinal (GI) and genito-urinary (GU) signs and symptoms were evaluated according to the Radiation Therapy Oncology Group (RTOG) toxicity scales. Median prescribed dose was 76 Gy. Median follow-up time was of 26.1 months.

RESULTS

From the 125 patients, 73 (58.4%) presented acute Grade 1 or Grade 2 GI and 97 (77.2%) presented acute Grade 1 or Grade 2 GU toxicity. Grade 3 GI acute toxicity occurred in only 2 patients (1.6%) and Grade 3 GU acute toxicity in only 3 patients (2.4%). Regarding Grade 1 and 2 late toxicity, 26 patients (20.8%) and 21 patients (16.8%) presented GI and GU toxicity, respectively. Grade 2 GI late toxicity occurred in 6 patients (4.8%) and Grade 2 GU late toxicity in 4 patients (3.2%). None patient presented any Grade 3 or higher late toxicity. Non-conformity to DVH constraints occurred in only 11.2% of treatment plans. On univariate analysis, no significant risk factor was identified for Grade 2 GI late toxicity, but mean dose delivered to the PTV was associated to higher Grade 2 GU late toxicity (p = 0.042).

CONCLUSION

IMRT is a well tolerable technique for routine treatment of localized prostate cancer, with short and medium-term acceptable toxicity profiles. According to the data presented here, rigid compliance to DHV constraints might prevent higher incidences of normal tissue complication.

High Dose Rate Brachytherapy as a Boost for the Treatment of Localized Prostate Cancer

PURPOSE

We report the outcome and toxicities of high dose rate brachytherapy as a boost for localized prostate cancer.

MATERIALS AND METHODS

Between 1996 and 2003, 309 patients with prostate carcinoma were treated with external beam radiation therapy and high dose rate brachytherapy. Furthermore, 36% of the patients received neoadjuvant/concurrent or adjuvant androgen deprivation therapy. Patients were stratified into 3 groups. Group 1 of 67 patients had Gleason score 6 or less, pretreatment prostate specific antigen 10 ng/ml or less and clinical stage T2a or less. Group 2 of 109 patients had Gleason score 7 or greater, pretreatment prostate specific antigen greater than 10 ng/ml and clinical stage T2b or greater. Group 3 of 133 patients had 2 or more of these higher risk factors.

RESULTS

At a median followup of 59 months the 5-year biochemical control rate, as defined by the American Society for Therapeutic Radiation and Oncology, was 86%, cause specific survival was 98% and overall survival was 91%. Biochemical control in stratified groups 1 to 3 was 98%, 90% and 78%, respectively. On univariate analysis risk group, pretreatment prostate specific antigen and Gleason score were significant predictors of biochemical control. However, on multivariate analysis only risk group and pretreatment prostate specific antigen were significant. Using the Common Toxicity Criteria scale there were 2 cases of grade 3 acute urinary toxicity. Regarding late side effects 4% of patients had grade 3 genitourinary toxicity and 1 had a grade 4 rectal complication.

CONCLUSIONS

External beam radiation therapy and high dose rate brachytherapy for prostate cancer resulted in excellent biochemical control, cause specific survival and overall survival with minimal severe acute or late complications.

Is seminal vesicle implantation with permanent sources possible? A dose–volume histogram analysis in patients undergoing combined 103Pd implantation and external beam radiation for T3c prostate cancer

PURPOSE

Combined brachytherapy and external beam radiation therapy (EBRT) of the prostate and seminal vesicles (SVs) is evolving as a successful treatment option for high-risk prostate cancer. Dose-volume histogram (DVH) analysis of the SV was performed in patients with biopsy-positive SV who received implantation of the SV and prostate.

METHODS AND MATERIALS

Fifteen consecutive patients with high-risk features (prostate-specific antigen [PSA] > or =10 ng/mL, Gleason score > or = 7, or clinical stage > or = T2b) and a positive SV biopsy were treated with a 103Pd implant of the prostate and SV followed by 45Gy of EBRT. DVHs were generated for the prostate and total SV volume (SVT). In addition, the SV was divided into 3-mm-thick volumes identified as SV1, SV2, SV3, SV4, SV5, and SV6 starting from the junction of the prostate and SV and extending distally. Delivered dose was defined as the D90 (dose delivered to 90% of the organ on DVH).

RESULTS

The median number of seeds implanted into the prostate and the SVT was 59 (41-94) and 9 (4-21), respectively. The median D90 values for the prostate, SVT, SV1, SV2, SV3, SV4, SV5, and SV6 were 103.2 (87.4-137.1), 46.2 (4.0-69.4), 76.0 (31.2-147), 63.4 (25.1-145.9), 49.7 (15.3-118), 27.4 (9.3-135.1), 14.2 (2.3-100.3), and 3.9 (0-61.5) Gy, respectively.

CONCLUSIONS

Implantation of the SV using a real-time intraoperative approach is technically feasible and results in higher doses to the SV than has been reported with implantation of the prostate alone. Although dose distribution in the SV can be variable and unpredictable, these doses, in combination with 45 Gy of EBRT, may be adequate to control disease spread in these organs.

Improvements in prostate brachytherapy dosimetry due to seed stranding

PURPOSE

Prostate brachytherapy with suture embedded seeds has emerged as a popular technique to reduce seed migration and to improve dosimetry. Various trials have shown improved dosimetry with seed fixity, whereas others have shown no benefit and possible detriment to suture embedded seeds. In order to contribute to the understanding of whether seed stranding improves dosimetry, we present retrospective data from our institution.

METHODS AND MATERIALS

We analyzed 80 patients treated between April 29, 2001 and June 19, 2006, receiving I-125 monotherapy for prostate cancer. Brachytherapy patients at the University of California, Los Angeles (UCLA) were initially treated using a transperineal approach with loose seeds. Subsequent to October 26, 2002, all patients were implanted using suture embedded seeds. Dosimetric quantifiers were calculated based on a CT obtained 1-month postimplantation.

RESULTS

Dosimetry of patients treated with stranded seeds showed significant improvement. Specifically, the V100 (volume of the prostate receiving 100% of the prescribed dose) improved from 88% to 92% (p<0.05), and the D90 (maximum dose received by 90% of the prostate) improved from 143 to 155 Gy (p<0.05).

CONCLUSIONS

At UCLA, the use of suture embedded seeds resulted in a significant improvement in our dosimetric quantifiers. Based upon other published studies, this improvement in dosimetry may translate into improved patient outcomes.

A magnetic resonance imaging study of prostate deformation relative to implanted gold fiducial markers

PURPOSE

To describe prostate deformation during radiotherapy and determine the margins required to account for prostate deformation after setup to intraprostatic fiducial markers (FM).

METHODS AND MATERIALS

Twenty-five patients with T1c-T2c prostate cancer had three gold FMs implanted. The patients presented with a full bladder and empty rectum for two axial magnetic resonance imaging (MRI) scans using a gradient recalled echo (GRE) sequence capable of imaging the FMs. The MRIs were done at the time of radiotherapy (RT) planning and a randomly assigned fraction. A single observer contoured the prostate surfaces. They were entered into a finite element model and aligned using the centroid of the three FMs.

RESULTS

During RT, the prostate volume decreased by 0.5%/fraction (p = 0.03) and the FMs in-migrated by 0.05 mm/fraction (p < 0.05). Prostate deformation was unrelated to differential bladder and bowel filling, but was related to a transurethral resection of the prostate (TURP) (p = 0.003). The standard deviation for systematic uncertainty of prostate surface contouring was 0.8 mm and for FM centroid localization was 0.4 mm. The standard deviation of random interfraction prostate deformation was 1.5 mm and for FM centroid variability was 1.1 mm. These uncertainties from prostate deformation can be incorporated into a margin recipe to determine the total margins required for RT.

CONCLUSIONS

During RT, the prostate exhibited: volume decrease, deformation, and in-migration of FMs. Patients with TURPs were prone to prostate deformation.

The role and strategy of IMRT in radiotherapy of pelvic tumors: Dose escalation and critical organ sparing in prostate cancer

PURPOSE

To investigate the intensity-modulated radiotherapy (IMRT) strategy in dose escalation of prostate and pelvic lymph nodes.

METHODS AND MATERIALS

Plan dosimetric data of 10 prostate cancer patients were compared with two-dimensional (2D) or IMRT techniques for pelvis (two-dimensional whole pelvic radiation therapy [2D-WPRT] or IM-WPRT) to receive 50 Gy or 54 Gy and additional prostate boost by three-dimensional conformal radiation therapy or IMRT (3D-PBRT or IM-PBRT) techniques up to 72 Gy or 78 Gy. Dose-volume histograms (DVHs), normal tissue complication probabilities (NTCP) of critical organ, and conformity of target volume in various combinations were calculated.

RESULTS

In DVH analysis, the plans with IM-WPRT (54 Gy) and additional boost up to 78 Gy had lower rectal and bladder volume percentage at 50 Gy and 60 Gy, compared with those with 2D-WPRT (50 Gy) and additional boost up to 72 Gy or 78 Gy. Those with IM-WPRT (54 Gy) also had better small bowel sparing at 30 Gy and 50 Gy, compared with those with 2D-WPRT (50 Gy). In NTCP, those with IM-WPRT and total dose of 78 Gy achieved lower complication rates in rectum and small bowel, compared with those of 2D-WPRT with total dose of 72 Gy. In conformity, those with IM-WPRT had better conformity compared with those with 2D-WPRT with significance (p < 0.005). No significant difference in DVHs, NTCP, or conformity was found between IM-PBRT and 3D-PBRT after IM-WPRT.

CONCLUSIONS

Initial pelvic IMRT is the most important strategy in dose escalation and critical organ sparing. IM-WPRT is recommended for patients requiring WPRT. There is not much benefit for critical organ sparing by IMRT after 2D-WPRT.

Radiation dose and late failures in prostate cancer

PURPOSE

To quantify the impact of radiation dose escalation on the timing of biochemical failure (BF) and distant metastasis (DM) for prostate cancer treated with radiotherapy (RT) alone.

METHODS

The data from 667 men with clinically localized intermediate- and high-risk prostate cancer treated with three-dimensional conformal RT alone were retrospectively analyzed. The interval hazard rates of DM and BF, using the American Society for Therapeutic Radiology and Oncology (ASTRO) and Phoenix (nadir + 2) definitions, were determined. The median follow-up was 77 months.

RESULTS

Multivariate analysis showed that increasing radiation dose was independently associated with decreased ASTRO BF (p < 0.0001), nadir + 2 BF (p = 0.001), and DM (p = 0.006). The preponderance (85%) of ASTRO BF occurred at < or =4 years after RT, and nadir + 2 BF was more evenly spread throughout Years 1-10, with 55% of BF in < or =4 years. Radiation dose escalation caused a shift in the BF from earlier to later years. The interval hazard function for DM appeared to be biphasic (early and late peaks) overall and for the <74-Gy group. In patients receiving > or =74 Gy, a reduction occurred in the risk of DM in the early and late waves, although the late wave appeared reduced to a greater degree.

CONCLUSION

The ASTRO definition of BF systematically underestimated late BF because of backdating. Radiation dose escalation diminished and delayed BF; the delay suggested that local persistence may still be present in some patients. For DM, a greater radiation dose reduced the early and late waves, suggesting that persistence of local disease contributed to both.

[External beam radiotherapy on locally advanced prostate carcinoma following iliac staging lymphadenectomy]

INTRODUCTION AND OBJECTIVES

Locally advanced prostate cancer supposes a high risk condition of post-treatment progression due to the limit situation that represents. Our purpose was to analyze prognoses factors in function of progression probability after using a treatment with external source radiotherapy on patients with this kind of tumors.

MATERIAL AND METHODS

We retrospectively reviewed a set of 128 patients submitted to pelvic staging limphadenectomy prior to accomplish an external radiotherapeutic treatment. We employed the Kaplan-Meier curves to study the probability of progression, logarithmic ranks test were used for detection of possible statistically significant differences and proportional risks Cox model was employed to study possible risk factors of progression (employing astro criteria).

RESULTS

5 years freedom probability from progression was of 49,93%; in spite of appreciating important differences in the groups stratified by the predictive variables used (total PSA, gleason of pathological biopsy, clinical stage and % of cores affection on biopsy), none of them reached statistical meaning, being the level of total PSA the closest to it.

CONCLUSIONS

The external radiotherapeuthic treatment represents a valid alternative in the treatment of locally advanced prostate cancer, with a tolerable index of secondaries. It must be used combined with hormonotherapy. It seems that the use of higher radiation doses, in a safer way thanks to 3D conformed radiotherapy, allows to improve the results. The most powerful clinical predictor of evolution must be the total PSA.

Dose distribution in 3-dimensional conformal radiotherapy for prostate cancer: Comparison of two treatment techniques (six coplanar fields and two dynamic arcs)

PURPOSE

To compare dose distribution for two techniques of 3-dimensional conformal radiotherapy (RT): 6-field technique (6F) and 2-dynamic arc therapy (2DA).

METHODS AND MATERIALS

Thirty nonmetastatic prostate cancer patients were included. In each patient, two treatment plans were prepared: with six coplanar fields (45 degrees , 90 degrees , 135 degrees , 225 degrees , 270 degrees , 315 degrees ) and with two dynamic lateral 100 degrees -wide arcs (40-140 degrees , 220-320 degrees ). Dose-volume histograms (DVHs) were computed and mean area under curve (AUC) values were calculated for the DVHs of Planning Target Volume (PTV), rectum, urinary bladder and femoral heads. Doses given to 30% of rectum (DR(30)), to 60% of rectum (DR(60)), to 50% of bladder (DB(50)), to 50% of femoral head (DF(50)) and to 95% of PTV (DPTV(95)) were reported as a percentage of the total dose.

RESULTS

Mean DR(30) and DR(60) for 6F and 2DA were 75.8%, 51.5% and 72.2%, 37.2%, respectively. Mean DB(50) for 6F and 2DA were 68% and 64.2%, respectively. Mean right DF(50) for 6F and 2DA were 35.4% and 45.5%, respectively. Mean DPTV(95) for 6F and 2DA were 99% and 99.2%, respectively. Mean AUCs of DVHs of rectum and urinary bladder were significantly higher for 6F (this was more evident for small PTV and in the intermediate dose range). Mean AUC of DVHs of PTV and femoral heads were significantly higher for 2DA.

CONCLUSIONS

Both 6F and 2DA offer good dose distribution for PTV. 2DA allows for significantly better sparing of rectum and urinary bladder with slightly worse femoral head dose distribution. Further study is warranted in order to establish the clinical relevance of these differences.

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.

[Localized prostate cancer. Local treatment and what place for lymphadenectomy]

The pretreatment PSA level, the Gleason score, the presence of lymph-node metastases, the status of surgical positive margins are poor pathological risk factors for patients who have a pathologic stage T3 prostate cancer. The increase in PSA level during the year prior to diagnostic is associated with the risk of death due to prostate cancer following radical prostatectomy or external beam radiation therapy. The assessment of Locoregional extension is indicated for such patients. The extended pelvic lymphadenectomy remains the most accurate procedure for a correct staging of the detection of nodal involvement in these patients with high-risk localized prostate cancer. For such patients with a high-risk of progression and, whose the life expectancy is greater than 10 years, treatment must be a combined modality therapy since radical prostatectomy alone correlates with a poor clinical outcome. Adjuvant hormonal therapy following local curative treatment by prostatectomy (or radiotherapy) needs to be often considered. Collegial decision-making is by far the most appropriate setting for the discussion among medical specialists of these complex clinical cases for patients often having associated medical conditions and whose adjuvant treatment will have a significant impact of their future quality of life.

Toxicity following high-dose salvage radiotherapy after radical prostatectomy

OBJECTIVE

To assess gastrointestinal (GI) and genitourinary (GU) toxicity in patients treated with salvage radiotherapy (SRT) at doses of 70.2 Gy after radical retropubic prostatectomy (RRP).

PATIENTS AND METHODS

Medical records were reviewed retrospectively to identify patients treated with SRT after RRP between January 1999 and December 2005. Of the 62 patients identified, 30 were included for analysis. GI and GU toxicity was assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events and the American Urological Association Symptom Index (AUASI), respectively.

RESULTS

The median AUASI score of the 17 patients with scores before SRT was 4, of the 24 with scores after SRT was 6, and of the 15 with scores before and after SRT the median increase was 3. Of the 29 patients with GI toxicity data, nine (31%) had diarrhoea after SRT (three after <70.2 Gy and six after 70.2 Gy). In all cases, the diarrhoea was mild (grade 1). Of all patients, 12 (41%) had proctitis after SRT (four after <70.2 Gy and eight after 70.2 Gy); the proctitis was grade 1 in four and grade 2 in eight, with no cases of grade 3 proctitis. There was no statistically significant difference in the median change in AUASI scores and GI toxicity incidence between patients receiving <70.2 or 70.2 Gy of SRT.

CONCLUSION

High-dose SRT (70.2 Gy) is generally well tolerated with acceptable low-grade GI toxicity and minimal changes in AUASI scores.

Radiation dose escalation combined with hormone therapy improves outcome in localised prostate cancer

We present the impact of systematic radiation dose escalation from 64 Gy to 66 Gy to 70 Gy on the outcome after radiation therapy (RT) alone or combined with hormonal treatment (HT) in a series of 494 consecutive localised prostate cancer patients treated during 1990-1999. Prognostic factors for prostate-specific antigen (PSA) failure, overall survival (OS) and prostate cancer specific survival (CSS) were investigated using multivariate analysis. T stage, pre-treatment PSA, grade, radiation dose and HT were found to be independent predictors of PSA failure. T stage, grade and HT were also independent predictors of both OS and CSS, while radiation dose was a significant predictor for OS and indicated a trend (p = 0.07) for CSS. A dose of 70 Gy combined with hormonal treatment improves PSA failure free survival and survival in localised prostate cancer compared with doses of 64-66 Gy.

Intensity-modulated radiotherapy improves lymph node coverage and dose to critical structures compared with three-dimensional conformal radiation therapy in clinically localized prostate cancer

PURPOSE

The aim of this study was to quantify gains in lymph node coverage and critical structure dose reduction for whole-pelvis (WP) and extended-field (EF) radiotherapy in prostate cancer using intensity-modulated radiotherapy (IMRT) compared with three-dimensional conformal radiotherapy (3DCRT) for the first treatment phase of 45 Gy in the concurrent treatment of lymph nodes and prostate.

METHODS AND MATERIALS

From January to August 2005, 35 patients with localized prostate cancer were treated with pelvic IMRT; 7 had nodes defined up to L5-S1 (Group 1), and 28 had nodes defined above L5-S1 (Group 2). Each patient had 2 plans retrospectively generated: 1 WP 3DCRT plan using bony landmarks, and 1 EF 3DCRT plan to cover the vascular defined volumes. Dose-volume histograms for the lymph nodes, rectum, bladder, small bowel, and penile bulb were compared by group.

RESULTS

For Group 1, WP 3DCRT missed 25% of pelvic nodes with the prescribed dose 45 Gy and missed 18% with the 95% prescribed dose 42.75 Gy, whereas WP IMRT achieved V(45 Gy) = 98% and V(42.75 Gy) = 100%. Compared with WP 3DCRT, IMRT reduced bladder V(45 Gy) by 78%, rectum V(45 Gy) by 48%, and small bowel V(45 Gy) by 232 cm3. EF 3DCRT achieved 95% coverage of nodes for all patients at high cost to critical structures. For Group 2, IMRT decreased bladder V(45 Gy) by 90%, rectum V(45 Gy) by 54% and small bowel V(45 Gy) by 455 cm3 compared with EF 3DCRT.

CONCLUSION

In this study WP 3DCRT missed a significant percentage of pelvic nodes. Although EF 3DCRT achieved 95% pelvic nodal coverage, it increased critical structure doses. IMRT improved pelvic nodal coverage while decreasing dose to bladder, rectum, small bowel, and penile bulb. For patients with extended node involvement, IMRT especially decreases small bowel dose.

A Randomized Trial Comparing Radical Prostatectomy Plus Endocrine Therapy versus External Beam Radiotherapy Plus Endocrine Therapy for Locally Advanced Prostate Cancer: Results at Median Follow-up of 102 Months

BACKGROUND

To investigate the optimal treatment of locally advanced prostate cancer, a prospective randomized trial was conducted to compare radical prostatectomy plus endocrine therapy versus external beam radiotherapy plus endocrine therapy.

METHODS

One hundred patients with T2b-3N0M0 prostate cancer were enrolled and 95 were evaluated. Of 95 cases, 46 underwent radical prostatectomy with pelvic lymph node dissection and 49 were treated with external beam radiation by linear accelerator with 40-50 Gy to the whole pelvis and 20-Gy boost to the prostatic area. For all patients, endocrine therapy was initiated 8 weeks before surgery or radiotherapy and continued thereafter. The long-term outcome and morbidity were examined.

RESULTS

Median follow-up period was 102 months. At 10 years overall survival rates in the surgery group were better than the radiation group (76.2% versus 71.1% for biochemical progression-free rates; P=0.25, 83.5% versus 66.1% for clinical progression-free rates; P=0.14, 85.7% versus 77.1% for cause-specific survival rates; P=0.06, and 67.9% versus 60.9% for overall survival rates; P=0.30), although none of them reached statistical significance. Erectile dysfunction was recognized in almost all patients as a result of continuous endocrine therapy. Incontinence requiring more than one pad per day was observed more frequently in the surgery group than the radiation group (P<0.01).

CONCLUSIONS

For the treatment of patients with locally advanced prostate cancer, when combined with endocrine therapy, either radical prostatectomy or external beam radiotherapy demonstrated favorable long-term outcomes. The radiation dose of 60-70 Gy might not be enough for the local treatment of locally advanced prostate cancer.

Current Status of HIFU and Cryotherapy in Prostate Cancer – A Review

OBJECTIVES

To evaluate the current status of high-intensity focused ultrasound (HIFU) and cryosurgery as the primary treatment option in patients with prostate cancer.

METHOD

A MedLine search using specified search terms was done on February 28, 2005. This search rendered 150 papers related to HIFU and 566 papers related to cryosurgery. Very few of these papers presented original outcome data and are included in the present review.

RESULTS

No controlled trial was available for analysis, and no survival data were presented. No validated biochemical, surrogate end point was available for any of the two therapies. HIFU showed progression-free survival (based on prostate-specific antigen+/-biopsy data) of 63-87% (projected 3- to 5-yr data), but median follow-up in the studies ranged from 12-24 mo. Negative postoperative biopsies was seen in 82-94% of patients. Complications have been reduced by the combination of transurethral resection of the prostate and HIFU. Cryosurgery showed a progression-free survival of 36-92% (projected 1-7 yr data), depending on risk groups and definition of failure. Negative biopsies were seen in 72-87%, but no biopsy data were available for the currently used third-generation cryotherapy machines. Complications seem to be lower with the third-generation machines.

CONCLUSIONS

None of the evaluated therapies has enough data available to support their use as an alternative to established therapies (surgery, radiation) for localised prostate cancer. Until further data become available, the use of both treatments should be restricted to patients unfit for established therapies who still have the need for local therapy.

Relationship between delay in radiotherapy and biochemical control in prostate cancer

PURPOSE

The aim of this study was to investigate whether a delay in radiotherapy is associated with a poorer biochemical control for prostate cancer.

METHODS

The time to treatment (TTT) from diagnosis of prostate cancer to radiotherapy was analyzed with respect to prostate-specific antigen (PSA) control in 1024 hormone-naive patients. The Kaplan-Meier PSA control curves for patients with TTT less than the median were compared with those for patients with TTT greater than the median in 3 predefined risk groups. Statistical significant differences in PSA control were further analyzed using Cox multivariate analysis with pretreatment PSA, Gleason score, T stage, and radiotherapy dose as covariates.

RESULTS

The median TTT and median follow-up are 3.7 months and 49 months respectively. Patients with a longer TTT have a statistically significant better PSA control than patients with a shorter TTT if they have intermediate- or high-risk disease. However in multivariate analysis TTT was not found to be significant in predicting PSA control, with pretreatment PSA and Gleason score emerging as highly significant in predicting PSA failure in both intermediate- and high-risk disease.

CONCLUSION

In this study in prostate cancer patients in British Columbia, there was no evidence that a longer time interval between diagnosis and radiotherapy was associated with poorer PSA control.

Case-Matched comparison of contemporary radiation therapy to surgery in patients with locally advanced prostate cancer

PURPOSE

Few studies critically compare current radiotherapy techniques to surgery for patients with locally advanced prostate cancer, despite an urgent need to determine which approach offers superior cancer control. Our objective was to compare rates of biochemical relapse-free survival (BFS) and surrogates of disease specific survival among men with high risk adenocarcinoma of the prostate as a function of treatment modality.

METHODS AND MATERIALS

Retrospective data from 409 men with prostate-specific antigen (PSA) > or =10 or Gleason 7-10 or Stage > or =T2b cancer treated uniformly at one university between March 1988 and December 2000 were analyzed. Patients had undergone radical prostatectomy (RP), brachytherapy implant alone (BTM), or external beam radiotherapy with brachytherapy boost with short-term neoadjuvant and adjuvant androgen deprivation therapy (BTC). From the total study population a 1:1 matched-cohort analysis (208 patients matched via prostate-specific antigen, Gleason score) comparing RP with BTC was performed as well.

RESULTS

Estimated 4-year BFS rates were superior for patients treated with BTC (BTC 72%, BTM 25%, RP 53%; p < 0.001). Matched analysis of BTC vs. RP confirmed these results (BTC 73%, BTM 55%; p = 0.010). Relative risk (RR) of biochemical relapse for BTM and BTC compared with RP were 2.92 (1.95-4.36) and 0.56 (0.36-0.87), (p < 0.001, p = 0.010). RR for BTC from the matched cohort analysis was 0.44 (0.26-0.74; p = 0.002).

CONCLUSIONS

High-risk prostate cancer patients receiving multimodality radiation therapy (BTC) display apparently superior BFS compared with those receiving surgery (RP) or brachytherapy alone (BTM).

Motion and shape change when using an endorectal balloon during prostate radiation therapy

PURPOSE

To investigate motion and shape change when using an endorectal balloon (ERB) in patients receiving radiotherapy for prostate cancer.

METHODS

In nine patients treated for prostate cancer using an ERB, the anterior wall of the ERB was contoured on right lateral images taken immediately before irradiation, and on left lateral images taken immediately after irradiation. Changes in the contours were used to calculate inter-fraction shape change and inter-imaging motion and shape change. Inter-imaging motion describes changes that occur after the right lateral image is taken that are seen in the left lateral image.

RESULTS

Eighty-six percent of all inter-imaging shifts of the anterior wall of the ERB were in the posterior direction (mean: 1.8 mm, 1 SD: 1.8 mm, maximum posterior shift: 2.8-7.2 mm). The inter-fraction shape change (1 SD) of the anterior wall was equivalent to a change in the angle of the balloon of 2.5-5.7 degrees, with a range of 8-20 degrees, depending on the patient. Inter-imaging shape changes were similar in size.

CONCLUSIONS

The inter-imaging motion and shape changes may be explained by the patient relaxing some time after insertion of the ERB, indicating that it could be reduced by a waiting period after insertion before irradiation. Development of image-guided localization strategies should consider intra-fraction motion and also inter- and intra-fraction shape change.

Dosimetric comparison of four target alignment methods for prostate cancer radiotherapy

PURPOSE

The aim of this study was to compare the dosimetric consequences of 4 treatment delivery techniques for prostate cancer patients treated with intensity-modulated radiotherapy (IMRT).

METHODS AND MATERIALS

During an 8-week course of radiotherapy, 10 patients underwent computed tomography (CT) scans 3 times per week (243 total) before daily treatment with a CT-linear accelerator. Treatment delivery was simulated by realigning a fixed-margin treatment plan on each CT scan and calculating doses. The alignment methods were those based on the following: skin marks, bony registration, ultrasonography (US), and in-room CT. For the last two methods, prostate was the alignment target. The dosimetric effects of these alignment methods on the prostate, seminal vesicles, rectum, and bladder were compared. The average daily minimum dose to 0.1 cm3 was used as the metric for target coverage.

RESULTS

Skin and bone alignments provided acceptable prostate coverage for only 70% of patients, US alignment for 90%, and CT alignment for 100%. CT-based alignment of the prostate provided seminal vesicle (SV) coverage of > or = 69 Gy for all patients; US and bone alignments provided SV coverage of > or = 60 Gy. This SV coverage may be acceptable for early-stage cancer (equivalent SV dose = 55.8 Gy at 1.8 Gy per fraction), but unacceptable for late-stage cancer (SV dose = 75.6 Gy). At 75.6 Gy, the acceptable rate for SV coverage was 40% for skin and bone alignments, 70% for US, and 80% for CT.

CONCLUSIONS

Direct target alignment methods (US and CT) provided better target coverage. CT-guided alignment provided the best and most consistent dosimetric coverage. A larger planning target volume margin is needed for SV coverage when the alignment target is the prostate.

Dispositifs de repositionnement prostatique sous l'accélérateur linéaire

The development of sophisticated conformal radiation therapy techniques for prostate cancer, such as intensity-modulated radiotherapy, implies precise and accurate targeting. Inter- and intrafraction prostate motion can be significant and should be characterized, unless the target volume may occasionally be missed. Indeed, bony landmark-based portal imaging does not provide the positional information for soft-tissue targets (prostate and seminal vesicles) or critical organs (rectum and bladder). In this article, we describe various prostate localization systems used before or during the fraction: rectal balloon, intraprostatic fiducials, ultrasound-based localization, integrated CT/linear accelerator system, megavoltage or kilovoltage cone-beam CT, Calypso 4D localization system tomotherapy, Cyberknife and Exactrac X-Ray 6D. The clinical benefit in using such prostate localization tools is not proven by randomized studies and the feasibility has just been established for some of these techniques. Nevertheless, these systems should improve local control by a more accurate delivery of an increased prescribed dose in a reduced planning target volume.

Clinical assessment of the use of the Sonarray system for daily prostate localization

The Sonarray ultrasound system is a non-invasive technique allowing real-time prostate localization. Since 2003, it has been used in our department before intensity modulated radiation therapy for prostate cancer. We reported both setup errors and organ motion detected by Sonarray system and the accuracy of this ultrasound imaging dedicated to radiotherapy.

Association of DNA repair and steroid metabolism gene polymorphisms with clinical late toxicity in patients treated with conformal radiotherapy for prostate cancer

OBJECTIVE

To explore the possible relationship between single nucleotide polymorphisms (SNP) in candidate genes encoding DNA damage recognition/repair/response and steroid metabolism proteins with respect to clinical radiation toxicity in a retrospective cohort of patients previously treated with three-dimensional conformal radiotherapy (3-DCRT) for prostate cancer.

EXPERIMENTAL DESIGN

One hundred twenty-four patients with prostate cancer underwent 3-DCRT at our institution between September 1996 and December 2000. Of these, 83 consented for follow-up of blood sampling and SNP analysis. Twenty-eight patients were documented as having experienced grade >/=2 late bladder or rectal toxicity (scoring system of Radiation Therapy Oncology Group) on at least one follow-up visit. We analyzed 49 SNPs in BRCA1, BRCA2, ESR1, XRCC1, XRCC2, XRCC3, NBN, RAD51, RAD52, LIG4, ATM, BCL2, TGFB1, MSH6, ERCC2, XPF, NR3C1, CYP1A1, CYP2C9, CYP2C19, CYP3A5, CYP2D6, CYP11B2, and CYP17A1 genes using the Pyrosequencing technique.

RESULTS

Significant univariate associations with late rectal or bladder toxicity (grade >/=2) were found for XRCC3 (A>G 5' untranslated region NT 4541), LIG4 (T>C Asp(568)Asp), MLH1 (C>T, Val(219)Ile), CYP2D6*4 (G>A splicing defect), mean rectal and bladder dose, dose to 30% of rectum or bladder, and age <60 years. On Cox multivariate analysis, significant associations with toxicity were found for LIG4 (T>C, Asp(568)Asp), ERCC2 (G>A, Asp(711)Asp), CYP2D6*4 (G>A, splicing defect), mean bladder dose >60 Gy, and dose to 30% of rectal volume >75 Gy.

CONCLUSIONS

In this study, we identified SNPs in LIG4, ERCC2, and CYP2D6 genes as putative markers to predict individuals at risk for complications arising from radiation therapy in prostate cancer.

Ultrasound-based image guided radiotherapy for prostate cancer: comparison of cross-modality and intramodality methods for daily localization during external beam radiotherapy

PURPOSE

To compare two different ultrasound-based verification systems for prostate alignment during daily external beam radiation therapy (EBRT) for localized prostate cancer.

METHODS AND MATERIALS

Prostate displacements were measured prospectively in 40 patients undergoing daily EBRT. Comparison was made between a system based on the cross-modality verification method (CMVM), which uses two different imaging modalities to assess organ motion, and a system based on the intramodality verification method (IMVM), which uses only one imaging modality for such assessment. A total of 217 CMVM and 217 IMVM displacements were collected within a minute of each other. In 10 patients, IMVM displacements were also compared with those measured by sequential CT scans.

RESULTS

Analysis in the paired CMVM and IMVM displacements shows a significant mean difference of 0.9 +/- 3.3 mm in the lateral and 6.0 +/- 5.1 mm in the superoinferior directions (p < 0.0001), whereas no significant difference was detected in the anteroposterior direction between the two methods. Comparison of the computed tomography scan and IMVM measured displacements shows no significant difference between the two methods, with mean values of 0.2 +/- 1.7 mm in the lateral, -0.3 +/- 1.6 mm in the anteroposterior, and 0.1 +/- 1.4 mm in the superoinferior directions.

CONCLUSIONS

A significant systematic difference exists between cross-modality and intramodality methods when assessing prostate alignment during daily EBRT. Because displacements assessed by IMVM are consistent with those assessed by computed tomography scan, a more accurate prostate alignment appears to be obtained when the IMVM method is used.

Long-term outcome of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer

PURPOSE

We report on the long-term results and late toxicity outcomes of high dose intensity modulated radiation therapy for patients with clinically localized prostate cancer.

MATERIALS AND METHODS

Between 1996 and 2000 a total of 561 patients with clinically localized prostate cancer were treated with intensity modulated radiation therapy. All patients were treated to a dose of 81 Gy prescribed to the planning target volume. Prostate specific antigen relapse was defined according to the American Society for Therapeutic Radiology and Oncology consensus and Houston definitions (absolute nadir plus 2 ng/ml dated at the call). Median followup was 7 years (range 5 to 9).

RESULTS

The 8-year actuarial PSA relapse-free survival rates for patients in favorable, intermediate and unfavorable risk groups according to the American Society for Therapeutic Radiology and Oncology definition were 85%, 76% and 72%, respectively (p <0.025). The 8-year actuarial prostate specific antigen relapse-free survival rates for patients in favorable, intermediate and unfavorable risk groups according to the Houston definition were 89%, 78% and 67%, respectively (p = 0.0004). The 8-year actuarial likelihood of grade 2 rectal bleeding was 1.6%. Three patients (0.1%) experienced grade 3 rectal toxicity requiring either 1 or more transfusions or a laser cauterization procedure. No grade 4 rectal complications have been observed. The 8-year likelihood of late grade 2 and 3 (urethral strictures) urinary toxicities were 9% and 3%, respectively. Among patients who were potent before intensity modulated radiation therapy, erectile dysfunction developed in 49%. The cause specific survival outcomes for favorable, intermediate and unfavorable risk cases were 100%, 96% and 84%, respectively.

CONCLUSIONS

These long-term results confirm our previous observations regarding the safety of high dose intensity modulated radiation therapy for clinically localized prostate cancer. Despite the application of high radiation doses, the incidence of rectal bleeding at 8 years was less than 2%. Despite the increased conformality of the dose distribution associated with intensity modulated radiation therapy, excellent long-term tumor control outcomes were achieved.

Matched-pair analysis of prostate cancer patients with a high risk of positive pelvic lymph nodes treated with and without pelvic RT and high-dose radiation using high dose rate brachytherapy

OBJECTIVE

Adding pelvic radiation to high-dose prostate radiation for prostate cancer patients with a >15% risk of positive lymph nodes (LN) is controversial. We performed a matched-pair analysis of patients treated at 2 institutions to assess the impact of pelvic radiotherapy (P-RT).

METHODS

From January 1993 to March 2003, 2 institutions treated 1432 prostate cancer patients with combined external beam radiotherapy (EBRT) and high-dose rate (HDR) brachytherapy. Those receiving EBRT were treated either to the prostate and seminal vesicles alone or to the entire pelvis (46 Gy). In all cases, prostate dose (EBRT and HDR) resulted in an average BED >100 Gy (alpha/beta = 1.2). There were 755 cases identified as having a pelvic LN risk >15% using the Roach formula. Of these, 255 cases were treated without pelvic RT and randomly matched by Gleason score, T stage, and pretreatment PSA to 500 cases treated with pelvic RT, resulting in 250 pairs (1:1).

RESULTS

Median follow-up was 4.0 years (P = 0.7). The 4-year prostate biochemical failure (22% versus 14%, P = 0.12), distant metastasis (9% versus 4%, P = 0.6), event-free survival (72% versus 78%, P = 0.3), prostate cancer death rate (4% versus 2%, P = 0.9), and overall survival (89% versus 88%, P = 0.7) were not significantly different for patients treated with and without P-RT. Analysis with and without androgen deprivation therapy showed similar results.

CONCLUSION

Improved biochemical, clinical, or survival outcomes were not observed for prostate cancer patients at risk for positive pelvic LN >15% when treated with high-dose EBRT and HDR brachytherapy to the prostate with or without pelvic radiation.

Dose Escalation with Three-dimensional Conformal Radiotherapy for Prostate Cancer. Is More Dose Really Better in High-risk Patients Treated with Androgen Deprivation?

AIMS

To determine the effect of radiation dose on biochemical control in prostate cancer patients treated in a single institution with three-dimensional conformal radiotherapy (3DCRT) and the additional effect of androgen deprivation in prostate cancer patients.

MATERIALS AND METHODS

In total, 363 men with T1-T3b prostate cancer treated in a sequential radiation dose-escalation trial from 66.0 to 84.1 Gy (International Commission Radiation Units and Measurement [ICRU] reference point) between 1995 and 2003, and with a minimum follow-up of 24 months, were included in the analysis. One hundred and forty-eight (41%) men were treated with 3DCRT alone; 74 (20%) men received neoadjuvant androgen deprivation (NAD) 4-6 months before and during 3DCRT; and 141 (39%) men received NAD and adjuvant androgen deprivation (AAD) 2 years after 3DCRT. Univariate, stratified and multivariate analyses were carried out separately for defined risk groups (low, intermediate and high) to determine the effect of radiation dose on biochemical control and its interaction with hormonal manipulation and clinical prognostic variables.

RESULTS

The median follow-up was 59 months (range 24-147 months). The actuarial biochemical disease-free survival (bDFS) at 5 years for all patients was 75% (standard error 3%). For low-risk patients, the bDFS was 82% (standard error 5%), for intermediate-risk patients it was 64% (standard error 6%) and for high-risk patients it was 77% (standard error 3%) (P = 0.031). In stratified and multivariate analyses, high-dose 3DCRT for all risk groups, and for high-risk patients, the use of long-term AAD vs NAD, contributed independently and significantly to improve the outcome of prostate cancer patients.

CONCLUSION

The present study indicates an independent benefit on biochemical outcome of high-dose 3DCRT for low-, intermediate- and high-risk patients and of long-term AAD in high-risk prostate cancer patients.

Low-dose rate prostate brachytherapy is well tolerated in patients with a history of inflammatory bowel disease

PURPOSE

We report on the follow-up of 24 patients with a prior history of inflammatory bowel disease (IBD) treated with brachytherapy for early-stage prostate cancer.

METHODS AND MATERIALS

Twenty-four patients with a history of inflammatory bowel disease (17 with ulcerative colitis (UC), 7 with Crohn's disease [CD]) underwent prostate brachytherapy between 1992 and 2004. Fifteen patients were treated with I-125 implantation and 6 patients were treated with Pd-103 alone or in combination with 45 Gy external beam radiation. Charts were reviewed for all patients, and all living patients were contacted by phone. National Cancer Institute common toxicity scores for proctitis were assigned to all patients. Actuarial risk of late toxicity was calculated by the Kaplan-Meier method. Statistical analysis was performed using SPSS software. Follow-up ranged from 3 to 126 months (median, 48.5 months; mean, 56.8 months).

RESULTS

None of the patients experienced Grade 3 or 4 rectal toxicity. Four patients experienced Grade 2 late rectal toxicity. The 5-year actuarial freedom from developing late Grade 2 rectal toxicity was 81%. At a median follow-up of 48.5 months, 23 patients were alive and had no evidence of disease with a median prostate-specific antigen for the sample of 0.1 ng/mL (range, <0.05-0.88 ng/mL). One patient died of other causes unrelated to his prostate cancer.

CONCLUSIONS

Prostate brachytherapy is well tolerated in patients with a history of controlled IBD. Therefore, brachytherapy should be considered a viable therapeutic option in this patient population.

Five-year prospective patient evaluation of bladder and bowel symptoms after dose-escalated radiotherapy for prostate cancer with the BeamCath® technique

PURPOSE

Late side effects were prospectively evaluated up to 5 years after dose-escalated external beam radiotherapy (EBRT) and were compared with a previously treated series with conventional conformal technique.

METHODS AND MATERIALS

Bladder and bowel symptoms were prospectively evaluated with the Prostate Cancer Symptom Scale (PCSS) questionnaire up to 5 years posttreatment. In all, 257 patients completed the questionnaire 5 years posttreatment. A total of 168 patients were treated with the conformal technique at doses<71 Gy, and 195 were treated with the dose-escalated stereotactic BeamCath technique comprising three dose levels: 74 Gy (n=68), 76 Gy (n=74), and 78 Gy (n=53).

RESULTS

For all dose groups analyzed together, 5 years after treatment, urinary starting problems decreased and urinary incontinence increased in comparison to baseline values. No increase in other bladder symptoms or frequency was detected. When comparing dose groups after 5 years, both the 74-Gy and 78-Gy groups reported increased urinary starting problems compared with patients given the conventional dose (<71 Gy). No increased incontinence was seen in the 76-Gy or the 78-Gy groups. Bowel symptoms were slightly increased during the follow-up period in comparison to baseline. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal late side effects after 5 years in comparison to doses<71 Gy.

CONCLUSION

Dose-escalated EBRT with the BeamCath technique with doses up to 78 Gy is tolerable, and the toxicity profile is similar to that observed with conventional doses<71 Gy.

Analysis of gene expression using gene sets discriminates cancer patients with and without late radiation toxicity

BACKGROUND

Radiation is an effective anti-cancer therapy but leads to severe late radiation toxicity in 5%-10% of patients. Assuming that genetic susceptibility impacts this risk, we hypothesized that the cellular response of normal tissue to X-rays could discriminate patients with and without late radiation toxicity.

METHODS AND FINDINGS

Prostate carcinoma patients without evidence of cancer 2 y after curative radiotherapy were recruited in the study. Blood samples of 21 patients with severe late complications from radiation and 17 patients without symptoms were collected. Stimulated peripheral lymphocytes were mock-irradiated or irradiated with 2-Gy X-rays. The 24-h radiation response was analyzed by gene expression profiling and used for classification. Classification was performed either on the expression of separate genes or, to augment the classification power, on gene sets consisting of genes grouped together based on function or cellular colocalization.X-ray irradiation altered the expression of radio-responsive genes in both groups. This response was variable across individuals, and the expression of the most significant radio-responsive genes was unlinked to radiation toxicity. The classifier based on the radiation response of separate genes correctly classified 63% of the patients. The classifier based on affected gene sets improved correct classification to 86%, although on the individual level only 21/38 (55%) patients were classified with high certainty. The majority of the discriminative genes and gene sets belonged to the ubiquitin, apoptosis, and stress signaling networks. The apoptotic response appeared more pronounced in patients that did not develop toxicity. In an independent set of 12 patients, the toxicity status of eight was predicted correctly by the gene set classifier.

CONCLUSIONS

Gene expression profiling succeeded to some extent in discriminating groups of patients with and without severe late radiotherapy toxicity. Moreover, the discriminative power was enhanced by assessment of functionally or structurally related gene sets. While prediction of individual response requires improvement, this study is a step forward in predicting susceptibility to late radiation toxicity.

High-dose irradiation for prostate cancer via a high-dose-rate brachytherapy boost: Results of a phase I to II study

OBJECTIVE

To evaluate outcomes of intermediate- and high-risk prostate cancer patients on a prospective dose-escalation study of pelvic external-beam radiation therapy (EBRT) combined with high-dose-rate (HDR) brachytherapy boost.

METHODS

From November 1991 to April 2003, 197 patients were treated for intermediate- and high-risk disease features. All patients had prostate-specific antigen>10 ng/ml, Gleason score>or=7, or clinical stage>or=T2b, and all received pelvic EBRT (46 Gy) while receiving either two or three HDR boost treatments. HDR dose fractionation increased progressively and was divided into two dose levels. The mean prostate biologic equivalency dose was 88.2 Gy for the low-dose group and 116.8 Gy for the high-dose group (alpha/beta=1.2). Clinical failure was either local failure or distant metastasis; clinical event-free survival (cEFS) was defined as patients who lived free of clinical failure.

RESULTS

Median follow-up was 4.9 years. The 5-year rates were as follows: biologic failure (BF), 18.6%, clinical failure (CF), 9.8%, cEFS 84.8%, cause-specific survival (CSS), 98.3%, and overall survival (OS), 92.9%. Five-year biochemical failure (68.7% vs. 86%, p<0.001), CF (6.1% vs. 15.6%, p=0.04), cEFS (75.5% vs. 91.7%, p=0.003), CSS (95.4% vs. 100%, p=0.02), and OS (86.2% vs. 97.8%, p=0.002) were significantly better for the high-dose group. Multivariate analysis showed that high-dose group (p=0.01, HR 0.35) and Gleason score (p=0.01, HR 1.84) were significant variables for cEFS. Multivariate analysis showed that high-dose group (p=0.01, HR 0.14) and age (p=0.03, HR 1.09 per year) were significant variables for overall survival.

CONCLUSION

There is a strong dose-response relationship for intermediate- to high-risk prostate cancer patients. Improved locoregional control with higher radiation doses alone can significantly decrease biochemical and clinical failures.