Mark K Buyyounouski

Stanford University, Palo Alto, California, United States

Are you Mark K Buyyounouski?

Claim your profile

Publications (149)476.82 Total impact

  • Mark K Buyyounouski
    European urology. 08/2014;
  • Journal of Clinical Oncology 04/2014; · 18.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Tadalafil is used to treat erectile dysfunction after prostate cancer treatment, but its role as a preventive agent is undefined. To determine primarily whether tadalafil preserved erectile function in men treated with radiotherapy for prostate cancer, and secondarily to determine whether participant- or partner-reported overall sexual function and sexual and marital satisfaction were affected. Stratified, placebo-controlled, double-blind, parallel-group study with 1:1 randomization at 76 community-based and tertiary medical sites in the United States and Canada. Two hundred forty-two participants with intact erectile function scheduled to receive radiotherapy for prostate cancer were recruited between November 2009 and February 2012 with follow-up through March 2013. One hundred twenty-one participants were assigned 5 mg of tadalafil daily and 121 were assigned placebo for 24 weeks starting with external radiotherapy (63%) or brachytherapy (37%). Participant-reported International Index of Erectile Function response before radiotherapy and at weeks 2 and 4, between weeks 20 and 24, between weeks 28 and 30, and 1 year thereafter. Participants and partners could respond also to the Sexual Adjustment Questionnaire and to the Locke Marital Adjustment Test before radiotherapy, between weeks 20 and 24 and weeks 28 and 30, and at 1 year. Primary outcome was off-drug spontaneous erectile function 28 to 30 weeks after radiotherapy started. Secondary end points were spontaneous erection at 1 year; overall sexual function and satisfaction; marital adjustment; and partner-reported satisfaction and marital adjustment at 28 to 30 weeks and 1 year, predictors of tadalafil response; and adverse events. Among 221 evaluable participants, 80 (79%; 95% CI, 70%-88%) assigned to receive tadalafil retained erectile function between weeks 28 and 30 compared with 61 (74%; 95% CI, 63%-85%) assigned to receive placebo (P = .49); an absolute difference of 5% (95% CI, -9% to 19%). A significant difference was also not observed at 1 year (72%; 95% CI, 60%-84% vs 71%; 95% CI, 59%-84%; P = .93). Tadalafil was not associated with significantly improved overall sexual function or satisfaction; a significant difference was not observed in any domain subscale. Partners of men assigned tadalafil noted no significant effect on sexual satisfaction, and marital adjustment was not significantly improved in participants or partners. Among men undergoing radiotherapy for prostate cancer, daily use of tadalafil compared with placebo did not result in improved erectile function. These findings do not support daily use of tadalafil to prevent erectile dysfunction in these patients. clinicaltrials.gov Identifier: NCT00931528.
    JAMA The Journal of the American Medical Association 04/2014; 311(13):1300-7. · 29.98 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To examine family history (FH) as a prognostic factor following radiotherapy (RT). Materials and methods Between 1989 and 2007, 1711 men with clinically localized prostate cancer and complete family history who had received RT (median RT dose = 74 Gy) without androgen deprivation therapy were analyzed. FH was defined as any prostate cancer in a first degree relative. For the biochemical failure (BF) outcome, this sample size has 85% power to detect a hazard ratio of 1.56 for positive versus negative FH. Results With a median follow-up of 71 months, there was no significant difference in the distribution of Gleason score (GS) or prostate specific antigen (PSA) based on FH. A positive FH was not an independent predictor of BF, distant metastasis (DM), prostate cancer specific mortality (PCSM), or overall mortality (OM) in Cox proportional multivariable analysis. On further analysis in a Cox proportional multivariable analysis, men with two or more first degree relatives with prostate cancer had a significantly higher likelihood of BF and DM than those with no FH, although there was no difference in PCSM or OM. Men with a positive FH (23%) were more likely to be younger, have a lower PSA, and non-palpable disease. There was no interaction between a positive FH and neither race nor treatment era (pre-PSA vs. PSA era). Conclusions A positive FH is not a prognostic factor following RT and should not alter standard treatment recommendations. Patients with two or more first degree relatives with prostate cancer had a higher likelihood of BF and DM, but there was no effect on survival. There was no interaction between a positive FH and African American race or treatment era. A positive FH was however, associated with more favorable PSA values and T-stage that may be the result of earlier screening.
    Radiotherapy and Oncology 01/2014; · 4.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To determine if escalated radiation dose using hypofractionation significantly reduces biochemical and/or clinical disease failure (BCDF) in men treated primarily for prostate cancer. Between June 2002 and May 2006, men with favorable- to high-risk prostate cancer were randomly allocated to receive 76 Gy in 38 fractions at 2.0 Gy per fraction (conventional fractionation intensity-modulated radiation therapy [CIMRT]) versus 70.2 Gy in 26 fractions at 2.7 Gy per fraction (hypofractionated IMRT [HIMRT]); the latter was estimated to be equivalent to 84.4 Gy in 2.0 Gy fractions. High-risk patients received long-term androgen deprivation therapy (ADT), and some intermediate-risk patients received short-term ADT. The primary end point was the cumulative incidence of BCDF. Secondarily, toxicity was assessed. There were 303 assessable patients with a median follow-up of 68.4 months. No significant differences were seen between the treatment arms in terms of the distribution of patients by clinicopathologic or treatment-related (ADT use and length) factors. The 5-year rates of BCDF were 21.4% (95% CI, 14.8% to 28.7%) for CIMRT and 23.3% (95% CI, 16.4% to 31.0%) for HIMRT (P = .745). There were no statistically significant differences in late toxicity between the arms; however, in subgroup analysis, patients with compromised urinary function before enrollment had significantly worse urinary function after HIMRT. The hypofractionation regimen did not result in a significant reduction in BCDF; however, it is delivered in 2.5 fewer weeks. Men with compromised urinary function before treatment may not be ideal candidates for this approach.
    Journal of Clinical Oncology 10/2013; · 18.04 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study attempted to determine whether the Gleason score (GS) assigned at a comprehensive cancer center better predicts risk of biochemical failure (BF) after prostate radiotherapy compared with the GS of the referring institution (RI). Between 1994 and 2007, 1649 men received radiotherapy for prostate cancer at Fox Chase Cancer Center (FCCC). The Cox proportional hazard regression was used for inferences about the relationship of time to BF and GS. Harrell's C-index (HCI) was used to assess concordance in the Cox regression between predicted and observed events. The discordance rate was 26% for any change in either major or minor Gleason pattern. In the RI GS 2 through 6 group, 79 (8%) patients were upgraded to GS 7. Twenty percent of patients with RI GS 7 were downgraded and 2% were upgraded. In the RI GS 8 through 9 group, 58% were downgraded to GS 6 (12%) or GS 7 (88%). The FCCC GS altered the NCCN risk group assignment in 144 men (9%): 92 (64%) men to lower risk and 52 (36%) to higher risk. FCCC GS was a stronger predictor of BF; the hazard ratios for GS 2 through 6 (ref), 3+4, 4+3, and 8 through 9 were 1.00 (ref), 1.82, 4.14, and 2.92, respectively. In contrast, the hazard ratios for the RI GS were 1.00 (ref), 1.53, 2.44, and 1.76, respectively. FCCC GS (HCI=0.76) had improved performance compared with RI GS (HCI=0.74). Changes in GS were common and the GS assigned by a comprehensive cancer center provided better BF risk stratification and prognostication for patients. Changes in GS may impact treatment recommendations in 9% to 26% of patients.
    Journal of the National Comprehensive Cancer Network: JNCCN 07/2013; 11(7):812-819. · 5.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We assessed effectiveness, safety, and tolerability of paclitaxel or fluorouracil when added to radiation plus cisplatin followed by adjuvant chemotherapy in a programme of selected bladder preservation for patients with muscle invasive bladder cancer. In our randomised phase 2 trial, we enrolled patients with T2-4a transitional cell carcinoma of the bladder at 24 medical centres in the USA. We randomly allocated patients to receive paclitaxel plus cisplatin (paclitaxel group) or fluorouracil plus cisplatin (fluorouracil group) with twice-daily radiation in random block sizes per site on the basis of clinical T-stage (T2 vs T3-4). Patients and physicians were aware of treatment assignment. All patients had transurethral resection of bladder tumour and twice-daily radiotherapy to 40·3 Gy, along with allocated chemotherapy, followed by cystoscopic and biopsy assessment of response. Patients who had a tumour response with downstaging to T0, Tcis, or Ta received consolidation chemoradiotherapy to 64·3 Gy, with the same chemotherapy regimen as in the induction phase. Patients received adjuvant cisplatin-gemcitabine-paclitaxel after the end of chemoradiotherapy. If, after induction, persistent disease was graded as T1 or worse, we recommended patients undergo cystectomy and adjuvant chemotherapy. We assessed the primary endpoints of rates of treatment completion and toxic effects in all randomly allocated patients. This study is registered with ClinicalTrials.gov, number NCT00055601. Between Dec 13, 2002, and Jan 11, 2008, we enrolled 97 patients, of whom 93 were eligible for analysis. Median follow-up was 5·0 years (IQR 5·0-6·2). Of 46 patients in the paclitaxel group, 45 (98%) completed induction (16 [35%] with grade 3-4 toxicity), 39 (85%) completed induction and consolidation (11 [24%] with grade 3-4 toxicity due to consolidation), and 31 (67%) completed the entire protocol with adjuvant chemotherapy. 34 (85%) of 40 assessable patients in the paclitaxel group had grade 3-4 toxicity during adjuvant chemotherapy. Of 47 patients in the fluorouracil group, 45 (96%) completed induction (nine [19%] with grade 3-4 toxicity), 39 (83%) completed induction and consolidation (12 [26%] had grade 3-4 toxicity due to consolidation), and 25 (53%) completed the entire protocol with adjuvant chemotherapy. 31 (76%) of 41 assessable patients in the fluorouracil group had grade 3-4 toxicity during adjuvant chemotherapy. Five (11%) patients treated with the paclitaxel regimen and three (6%) patients treated with the fluorouracil regimen developed late grade 3-4 radiotherapy toxicities. 11 (24%) patients treated with the paclitaxel regimen and 16 (34%) patients treated with the fluorouracil regimen developed late grade 3-4 toxicities unrelated to radiotherapy. One patient (in the fluorouracil group) died during follow-up. Six (13%) patients in the paclitaxel group and in three (6%) patients in the fluorouracil group discontinued due to treatment-related toxicity. In the absence of phase 3 data, our findings could inform selection of a bladder-sparing trimodality chemotherapy regimen for patients with muscle invasive bladder cancer. US National Cancer Institute.
    The Lancet Oncology 06/2013; · 25.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aims to quantify the reduction of the intrafractional motion when the prostate intensity modulated radiation therapy (IMRT) treatment time is shortened. Prostate intrafractional motion data recorded by the Calypso system for 105 patients was analyzed. Statistical distributions of the prostate displacements for the regular IMRT treatment and the first 1, 2, 3 and 5 min of the treatment were calculated and used for treatment margin estimation for all the selected patients. The treatment margins estimated for the first 1, 2, 3 and 5 min were compared with those for the regular IMRT treatment to quantify the reduction of the motion. If the treatment can be completed within 5 (3) min, the standard deviation of the prostate displacement could be reduced by up to 45% and the required treatment margins could be reduced to 1.2 (1.1), 0.9 (0.8), 2.2 (1.9), 1.9 (1.5), 1.9 (1.7) and 2.8 (2.4) mm from 1.5, 1.1, 2.8, 3.0, 2.4 and 3.9 mm in the left, right, superior, inferior, anterior and posterior directions, respectively. The same work was also performed for 19 of the 105 patients who exhibited the largest motion with 30% of their treatment time having 3D motion more than 3 mm. For this group of patients, the required margins change to 1.4 (1.2), 0.8 (0.8), 1.8 (1.6), 2.3 (1.8), 1.7 (1.5) and 3.4 (2.8) mm from 1.9, 1.2, 1.7, 3.7, 1.6 and 4.9 mm in the six directions when the treatment time is reduced to 5 (3) min. The intrafractional motion effects on prostate treatment are significantly smaller and the required margins can be therefore reduced when the treatment is shortened.
    Physics in Medicine and Biology 06/2013; 58(14):4921-4932. · 2.70 Impact Factor
  • Mark K Buyyounouski
    Nature Reviews Urology 06/2013; · 4.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: There are no well-established normal tissue sparing dose-volume histogram (DVH) criteria that limit the risk of urinary toxicity from prostate radiation therapy (RT). The aim of this study was to determine which criteria predict late toxicity among various DVH parameters when contouring the entire solid bladder and its contents versus the bladder wall. The area under the histogram curve (AUHC) was also analyzed. METHODS AND MATERIALS: From 1993 to 2000, 503 men with prostate cancer received 3-dimensional conformal RT (median follow-up time, 71 months). The whole bladder and the bladder wall were contoured in all patients. The primary endpoint was grade ≥2 genitourinary (GU) toxicity occurring ≥3 months after completion of RT. Cox regressions of time to grade ≥2 toxicity were estimated separately for the entire bladder and bladder wall. Concordance probability estimates (CPE) assessed model discriminative ability. Before training the models, an external random test group of 100 men was set aside for testing. Separate analyses were performed based on the mean age (≤ 68 vs >68 years). RESULTS: Age, pretreatment urinary symptoms, mean dose (entire bladder and bladder wall), and AUHC (entire bladder and bladder wall) were significant (P<.05) in multivariable analysis. Overall, bladder wall CPE values were higher than solid bladder values. The AUHC for bladder wall provided the greatest discrimination for late bladder toxicity when compared with alternative DVH points, with CPE values of 0.68 for age ≤68 years and 0.81 for age >68 years. CONCLUSION: The AUHC method based on bladder wall volumes was superior for predicting late GU toxicity. Age >68 years was associated with late grade ≥2 GU toxicity, which suggests that risk-adapted dose constraints based on age should be explored.
    International journal of radiation oncology, biology, physics 05/2013; · 4.59 Impact Factor
  • International journal of radiation oncology, biology, physics 05/2013; 86(1):6-7. · 4.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: INTRODUCTION: We report the long-term results of RTOG 9801, a randomized trial investigating the ability of amifostine, a radioprotector, to reduce chemoradiation-induced esophagitis. METHODS: Patients with stages II and IIIA/B non-small-cell lung cancer received induction paclitaxel 225mg/m2 intravenously (IV) and carboplatin area under the curve (AUC) 6 both days 1 and 22, followed by concurrent weekly paclitaxel (50mg/m2) and carboplatin (AUC 2), with hyperfractionated radiation therapy (69.6Gy at 1.2Gy BID). Patients were randomly assigned to amifostine (AM) 500mg IV four times per week or no-AM during chemoradiotherapy. Stratification factors included age (<70 vs. ≥70years), stage and performance status. RESULTS: 243 patients (pts) were enrolled; 120 received AM, 123 received no-AM. Two pts on each arm were found ineligible. Overall, 85% of patients were ≤70years; 75% had a KPS ≥90. 34% had squamous histology. With median follow-up of 96.3months (for patients still alive), overall survival was identical (hazard ratio 1.03 (0.79-1.34), NS): five-year survival 17% in both arms. The incidence of late grade 3-5 toxicities was 16% in the AM arm and 19% in the control arm (hazard ratio 1.24 (0.66-2.32), NS). There was no significant difference between the arms regarding overall survival, disease-free survival or long-term toxicity. CONCLUSION: The chemoradiation regimen of carboplatin and paclitaxel produced long-term results in the multi-institutional setting comparable to other regimens. Amifostine did not appear to compromise survival. As done in RTOG 9801, more consistent reporting of long term toxicity is needed for comparison of different chemoradiation regimens.
    Lung cancer (Amsterdam, Netherlands) 03/2013; · 3.14 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: A phase 3 Radiation Therapy Oncology Group (RTOG) study subset analysis demonstrated improved overall survival (OS) with the addition of stereotactic radiosurgery (SRS) to whole brain radiation therapy (WBRT) in non-small cell lung cancer (NSCLC) patients with 1 to 3 brain metastases. Because temozolomide (TMZ) and erlotinib (ETN) cross the blood-brain barrier and have documented activity in NSCLC, a phase 3 study was designed to test whether these drugs would improve the OS associated with WBRT + SRS. METHODS AND MATERIALS: NSCLC patients with 1 to 3 brain metastases were randomized to receive WBRT (2.5 Gy × 15 to 37.5 Gy) and SRS alone, versus WBRT + SRS + TMZ (75 mg/m(2)/day × 21 days) or ETN (150 mg/day). ETN (150 mg/day) or TMZ (150-200 mg/m(2)/day × 5 days/month) could be continued for as long as 6 months after WBRT + SRS. The primary endpoint was OS. RESULTS: After 126 patients were enrolled, the study closed because of accrual limitations. The median survival times (MST) for WBRT + SRS, WBRT + SRS + TMZ, and WBRT + SRS + ETN were qualitatively different (13.4, 6.3, and 6.1 months, respectively), although the differences were not statistically significant. Time to central nervous system progression and performance status at 6 months were better in the WBRT + SRS arm. Grade 3 to 5 toxicity was 11%, 41%, and 49% in arms 1, 2, and 3, respectively (P<.001). CONCLUSION: The addition of TMZ or ETN to WBRT + SRS in NSCLC patients with 1 to 3 brain metastases did not improve survival and possibly had a deleterious effect. Because the analysis is underpowered, these data suggest but do not prove that increased toxicity was the cause of inferior survival in the drug arms.
    International journal of radiation oncology, biology, physics 02/2013; · 4.59 Impact Factor
  • Brachytherapy 01/2013; · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Randomized trials have demonstrated that escalated-dose external-beam radiotherapy (EDRT) is better than standard-dose radiotherapy (SDRT) for patients with prostate cancer and that adding androgen-deprivation therapy (ADT) to SDRT is better than SDRT alone; however, no trials have compared EDRT versus SDRT plus ADT or EDRT versus EDRT plus ADT. The authors designed a model to estimate the results of various doses of radiotherapy (RT) combined with various durations of ADT. METHODS: From 1989 to 2007, 3215 men consecutively received definitive EDRT with or without ADT. In total, 2012 patients had complete records available for creating the nomogram. The duration of ADT varied for patients who received no RT (n = 1562), ≤6 months of RT (n = 145), from >6 months to <24 months of RT (n = 140), and ≥24 months of RT (n = 165) with a median follow-up of 65.7 months, 66.2 months, 60.1 months, and 63 months, respectively. The model included the following covariates: palpation T-category, biopsy Gleason score, the percentage of tumor cells with a Gleason pattern of 4 or 5, the percentage of tumor tissue, initial pretreatment prostate-specific antigen (PSA) level, ADT duration, and RT dose. Two nomograms, for outcomes with and without ADT, were created from a single competing-risks model. Biochemical failure was defined as a rise in serum PSA of 2 ng/mL over the post-treatment PSA nadir. RESULTS: According to the results from analyzing representative intermediate-risk to high-risk patient parameters, the gains from increasing the RT dose from 70 Gray (Gy) to 80 Gy were far less than the gains from adding ≥3 months of ADT. CONCLUSIONS: The nomograms provided unique patient-specific estimates of the effects of various doses and durations of RT and ADT. The results indicated that adding ADT to treatment for intermediate-risk and high-risk prostate cancer is far more beneficial than a modest RT dose escalation. Cancer 2012. © 2012 American Cancer Society.
    Cancer 10/2012; · 5.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate erectile function after high-dose radiotherapy for prostate cancer using the International Index of Erectile Function, Expanded Prostate Cancer Index Composite, and stamp test. Men with favorable and intermediate-risk prostate cancer were assigned to receive prostate intensity-modulated radiotherapy (IMRT) versus an erectile tissue-sparing IMRT technique in a Phase III randomized, prospective study. The stamp test and International Index of Erectile Function and Expanded Prostate Cancer Index Composite questionnaires were completed at baseline and 6 months, 1 year, and 2 years after IMRT. The Sexual Health Inventory for Men scores were abstracted from the International Index of Erectile Function questionnaire. A partner questionnaire, designated IIEF-P, modeled after the International Index of Erectile Function questionnaire but from the perspective of the partner, was also collected. The data from 94 men who were enrolled in the trial and who had completed ≥1 questionnaire or 1 stamp test were analyzed. The median age of the patient population was 62.5 years. The median radiation dose was 76 Gy (range 74-80). At 6 months and 1 year after high-dose IMRT, a positive stamp result correlated significantly with the median Expanded Prostate Cancer Index Composite sexual summary, sexual function, and bother subscale scores. Additionally, 6 months after IMRT, the stamp test correlated with the median International Index of Erectile Function, International Index of Erectile Function sexual function domain, and Sexual Health Inventory for Men scores. Robust concordance for the International Index of Erectile Function and Sexual Health Inventory for Men scores was appreciated between responding patient and partner pairs. Nocturnal tumescence, as indicated by a positive stamp test, correlated well with established quality of life questionnaires after IMRT. The stamp test should strongly be considered as an objective measure of erectile function in future studies of erectile dysfunction in patients with prostate cancer.
    Urology 06/2012; 80(2):337-42. · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Magnetic Resonance Spectroscopy (MRS) of the prostate is not used in radiotherapy departments on a regular basis due to a number of issues. The indication and severity of prostate cancer is related to the presence of choline in the prostate, in particular, the ratio of choline (plus creatine) to citrate. In-vivo data supports this theory only marginally but lacks strong correlation with biopsy data. The situation is further complicated by the lack of precise spatial information in biopsy, variation of magnetic susceptibility, and spatial dependence of MRS data on the distance from the endo-rectal coil. The latter also cause low signal-to-noise ratio (SNR). We intend to understand how the level of metabolite concentrations and spatial dependences determine what is observed in MRS. Methods: A spherical phantom is filled with water solutions containing various amounts of metabolites. It is placed on top of an endo-rectal coil with the balloon filled with per fluorocarbon. MRS data is acquired on a GE 1.5 T MR scanner. The metabolite values, their ratios etc as reported in GE software, FuncTool are studied as functions of metabolite concentrations in the phantom. Results: Analysis of the phantom data indicates that the metabolite ratio reported in FuncTool is approximately linearly correlated to the metabolite concentrations used in the phantom to a certain point and then saturates whereas the largest metabolite value is well correlated with its concentration in the phantom. All metabolite values become weaker and SNR lower as we move away from the coil. Conclusions: This work indicates the potential of using metabolite values directly provided their spatial dependences on the distance of the voxels from the endo-rectal coil can be accommodated.
    Medical Physics 06/2012; 39(6):3639-3640. · 2.91 Impact Factor
  • Js Li, M Buyyounouski, E Horwitz, C-M Ma
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To investigate the correlation between the post dosimetry and the real-time plan for the transrectal ultrasound guided prostate seed implant. Methods: Prostate seed implants were performed with preloaded needles and transrectal ultrasound imaging guidance. Customized stranded seeds based on the real time treatment plan generated in the operation room were preloaded in the needles for the implant. Post dosimetry was performed at the same day and three week later based on patient's CT and MR images. Target DVH parameters of the real-time plan and the post dosimetry at the week three were studied retrospectively for 100 patients. The correlation between them was analyzed and uncertainty of the prediction on the post dosimetry was calculated. Results: Though the post dosimetry meets clinic criteria for most of the patients, big uncertainty on the target dose is observed, 12.4% on D90 and 7.6% on V100. The correlation coefficient between the DVH parameters of the post dosimetry and the real time plan is poor. The mean ratio of the V100 (D90) between the post dosimetry and real time plan is 0.92 (0.88) with a standard deviation of 0.07 (0.1), which means on average that a 100% V100 is required in the real time plan for a 90% post dosimetry V100 and a 115% D90 for a 100% post dosimetry D90. The mean ratio between the post V100 (D90) and the real time V150 is 1.5 (1.76) with a standard deviation of 0.19 (0.25). The mean ratio of V200 between the post and the real time is 1.1 with a standard deviation of 0.4. Conclusions: In order to reduce the dosimetry uncertainty, the implant technique and the consistence need to be improved. The post dosimetry is necessary for patient dose evaluation because it cannot be predicted accurately based on the real time plan.
    Medical Physics 06/2012; 39(6):3933. · 2.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To present the largest retrospective series investigating the effect of aspirin and statins, which are hypothesized to have antineoplastic properties, on biochemical failure (nadir plus 2 ng/mL) after prostate radiation therapy (RT). Between 1989 and 2006, 2051 men with clinically localized prostate cancer received definitive RT alone (median dose, 76 Gy). The rates of aspirin use and statin use (defined as any use at the time of RT or during follow-up) were 36% and 34%, respectively. The primary endpoint of the study was an interval to biochemical failure (IBF) of less than 18 months, which has been shown to be the single strongest predictor of distant metastasis, prostate cancer survival, and overall survival after RT. Patient demographic characteristics and tumor staging factors were assessed with regard to associations with the endpoint. Univariate analysis was performed with the χ(2) test for categorical variables and the Wilcoxon test for continuous variables. Multivariable analysis was performed with a multiple logistic regression. The median follow-up was 75 months. Univariate analysis showed that an IBF of less than 18 months was associated with aspirin nonuse (P<.0001), statin nonuse (P<.0001), anticoagulant nonuse (P=.0006), cardiovascular disease (P=.0008), and prostate-specific antigen (continuous) (P=.008) but not with Gleason score, age, RT dose, or T stage. On multivariate analysis, only aspirin nonuse (P=.0012; odds ratio, 2.052 [95% confidence interval, 1.328-3.172]) and statin nonuse (P=.0002; odds ratio, 2.465 [95% confidence interval, 1.529-3.974]) were associated with an IBF of less than 18 months. In patients who received RT for prostate cancer, aspirin or statin nonuse was associated with early biochemical failure, a harbinger of distant metastasis and death. Further study is needed to confirm these findings and to determine the optimal dosing and schedule, as well as the relative benefits and risks, of both therapies in combination with RT.
    International journal of radiation oncology, biology, physics 05/2012; 84(1):e13-7. · 4.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: The objective of this study was to compare the prognostic value of the sixth and seventh editions of the American Joint Cancer Committee (AJCC) Cancer Staging Manual and the risk-stratification model of the National Comprehensive Cancer Network (NCCN). METHODS: Two-thousand four hundred twenty-nine men who received definitive radiotherapy with or without androgen-deprivation therapy (median follow-up, 74 months) were analyzed. RESULTS: There was a migration of stage II patients to stage I with AJCC seventh edition (stage I increased from 1% to 38%, and stage II decreased from 91% to 55%). One pair-wise comparison (4%) of Kaplan-Meier estimates of biochemical failure, distant metastasis, prostate cancer-specific survival, and overall survival between stages was statistically significant for the AJCC sixth edition. Conversely, 16 of 24 comparisons (67%) were significant for the AJCC seventh edition. With the NCCN risk-stratification model, 9 of 12 comparisons (75%) were significant. Concordance probability estimate (CPE) and standard error (SE) analysis indicated uniform and significant improvement in the predictive power of the AJCC seventh edition versus the sixth edition for all outcomes. CPE ± SE values for the AJCC seventh edition versus the sixth edition were 0.51 ± 0.009 versus 0.59 ± 0.02, respectively, for biochemical failure; 0.54 ± 0.02 versus 0.70 ± 0.05, respectively, for distant metastasis; 0.57 ± 0.009 versus 0.76 ± 0.007, respectively, for prostate cancer-specific survival; and 0.52 ± 0.006 versus 0.57 ± 0.01, respectively, for overall survival. CPE ± SE values for the NCCN model were 0.59 ± 0.02 for biochemical failure, 0.72 ± 0.05 for distant metastasis, 0.80 ± 0.01 for prostate cancer-specific survival, and 0.57 ± 0.01 for overall survival. CONCLUSIONS: The current results indicated that the seventh edition of the AJCC Cancer Staging Manual is a major improvement over the sixth edition, because it distributes patients better among the stages and is more prognostic. However, the NCCN model was superior to the AJCC seventh edition and remains the preferred method for risk-based clinical management of prostate cancer with radiotherapy. Cancer 2012;. © 2012 American Cancer Society.
    Cancer 04/2012; · 5.20 Impact Factor

Publication Stats

1k Citations
476.82 Total Impact Points

Institutions

  • 2013–2014
    • Stanford University
      • Department of Radiation Oncology
      Palo Alto, California, United States
    • Thomas Jefferson University Hospitals
      Philadelphia, Pennsylvania, United States
    • Temple University
      Philadelphia, Pennsylvania, United States
  • 2002–2013
    • Fox Chase Cancer Center
      • Department of Radiation Oncology
      Philadelphia, PA, United States
  • 2012
    • University of Miami Miller School of Medicine
      • Department of Radiation Oncology
      Miami, FL, United States
  • 2011
    • Mayo Foundation for Medical Education and Research
      • Department of Urology
      Scottsdale, AZ, United States
    • Cooper University Hospital
      • Department of Radiation Oncology
      Camden, New Jersey, United States
  • 2009
    • University of Melbourne
      Melbourne, Victoria, Australia