Search PubMed⌕ Search

Biomedical subjects

W Robert Lee

Publications and source records attributed to W Robert Lee.

At least 19 recordsLinked to original sources
PubMed2026

Participant Heterogeneity in the Prostate Cancer Biobank of the NRG: An Obstacle to Broadening the Reach of Precision Oncology.

PURPOSE: Precision medicine has revolutionized oncology; however, tumor biomarkers are not reflective of the heterogeneous cancer population. We evaluated NRG Oncology prostate cancer (PCa) clinical trials for demographic differences among patients with optional biospecimen collection (BC) consent and biospecimen submission (BSub). METHODS: Data from 19 NRG PCa clinical trials closed before 2015 were analyzed. Patients who consented to BC and completed BSub were evaluated by race, ethnicity, median income, area deprivation index (ADI; categorized as highest v lowest three quartiles), age at enrollment, site, and year of enrollment. T/chi-square tests were used for continuous/categorical variables, respectively, followed by logistic regression. RESULTS: Of the 15,648 randomized patients eligible for BC, 11,796 (75%) had specimens submitted. In all, 4,598 (82.2%) of 5,597 eligible patients consented for optional BC in nine clinical trials with a separate BC consent process (consent rates by race/ethnicity: 74.1% Black, 72.8% Hispanic/Latino, 83.8% White). A smaller proportion of Black and Hispanic/Latino patients consented to optional BC compared with those who did not (12.1% v 19.5% Black, P < .0001; 3.5% v 5.8% Hispanic, P = .0006). In univariable logistic regression models, high ADI (more socioeconomic disadvantage) was associated with a decreased likelihood for optional BC consent (odds ratio [OR], 0.67 [95% CI, 0.55 to 0.82]; P = .02), but not a decreased likelihood for BSub (OR, 0.74 [95% CI, 0.53 to 1.04]; P = .08). Multivariable models demonstrated that Black/Hispanic/Latino patients were less likely to consent to optional BC, and Black patients were less likely to have BSub (P < .05 for all). CONCLUSION: White/non-Hispanic patients and those with less socioeconomic disadvantage were more likely to consent to optional BC, whereas Black patients were less likely to have BSub. Targeted solutions are needed to improve biorepository representation so that precision medicine approaches better reflect the cancer population.

Aged↗
PubMed2006

Results of a phase II trial of transrectal ultrasound-guided permanent radioactive implantation of the prostate for definitive management of localized adenocarcinoma of the prostate (radiation therapy oncology group 98-05).

PURPOSE: To evaluate the effectiveness of transrectal ultrasound-guided permanent radioactive (125)I implantation of the prostate for organ-confined adenocarcinoma of the prostate compared with historical data of prostatectomy and external beam radiotherapy within a cooperative group setting. METHODS AND MATERIALS: Patients accrued to this study had histologically confirmed, locally confined, adenocarcinoma of the prostate with clinical Stage T1b, T1c, or T2a, no nodal or metastatic disease, prostate-specific antigen level of < or =10 ng/mL, and Gleason score of < or =6. All patients underwent transrectal ultrasound-guided radioactive (125)I permanent seed implantation into the prostate. The prescribed dose was 145 Gy to the prostate planning target volume. RESULTS: A total of 27 institutions accrued a total of 101 patients to this protocol, with no institution accruing >8 patients. Six patients were ineligible, leaving 95 properly entered as eligible in the study. The median follow-up was 5.3 years (range, 0.4-6.5 years). At 5 years, 5 patients had local failure, 1 had evidence of distant failure, and 6 (6%) had biochemical failure. The overall survival rate at 5 years was 96.7%. At last follow-up, no patient had died of prostate cancer or related toxicities. Eight patients had a maximal acute toxicity level of 3, and no patient had Grade 4 or 5 acute toxicity. During follow-up, 2 patients had maximal Grade 3 toxicity, both related to bladder issues, and no patient experienced Grade 4 or 5 toxicity. CONCLUSION: The results of this clinical protocol (a multi-institutional trial of brachytherapy for localized adenocarcinoma of the prostate) have demonstrated that this type of trial can be successfully completed through the Radiation Therapy Oncology Group. Biochemical disease-free survival was comparable with other brachytherapy published series and with the results after surgery and external beam radiotherapy.

Adenocarcinoma↗
PubMed2006

Percentage of positive biopsies associated with freedom from biochemical recurrence after low-dose-rate prostate brachytherapy alone for clinically localized prostate cancer.

OBJECTIVES: To examine the relationship between the percentage of positive biopsies (PPBs) and freedom from biochemical recurrence (FFBR) in men treated with low-dose-rate prostate brachytherapy (LDRPB) alone. The PPBs has been associated with FFBR in men treated with radical prostatectomy and external beam radiotherapy for prostate cancer. METHODS: This report concerns 108 men treated with LDRPB alone between November 1997 and December 1999. All patients had clinically localized prostate cancer confirmed by biopsy. All men were treated with iodine-125 to 144 Gy. FFBR was estimated using the product-limit method. Putative covariates for FFBR, including T stage, Gleason score, pretreatment prostate-specific antigen level, minimal dose received by 90% of the target volume, and PPBs, were examined using the proportional hazards regression model. RESULTS: The median follow-up was 61 months. Of the 108 men, 13 developed evidence of biochemical relapse at a median of 25 months. The 5-year estimate of FFBR was 87% (95% confidence interval 81% to 93%) for the entire cohort. On univariate analysis, prostate-specific antigen, T stage, minimal dose received by 90% of the target volume, and PPBs were associated with FFBR. In the multivariate model, the PPBs was the only variable that predicted for FFBR (P = 0.002). The 5-year estimate of FFBR was 95% for patients with less than 50% PPB disease versus 63% in patients with more than 50% PPB disease (P < 0.0001). CONCLUSIONS: The PPBs is an important independent predictor of FFBR after LDRPB alone. The FFBR after LDRPB in the group of patients with more than 50% PPBs was poor.

Aged↗
PubMed2006

Phase I-II prospective dose-escalating trial of lycopene in patients with biochemical relapse of prostate cancer after definitive local therapy.

OBJECTIVES: To report a prospective trial of lycopene supplementation in biochemically relapsed prostate cancer. METHODS: A total of 36 men with biochemically relapsed prostate cancer were enrolled in a dose-escalating, Phase I-II trial of lycopene supplementation. Six consecutive cohorts of 6 patients each received daily supplementation with 15, 30, 45, 60, 90, and 120 mg/day for 1 year. The serum levels of prostate-specific antigen (PSA) and plasma levels of lycopene were measured at baseline and every 3 months. The primary endpoints were PSA response (defined as a 50% decrease in serum PSA from baseline), pharmacokinetics, and the toxicity/tolerability of this regimen. RESULTS: A total of 36 patients were enrolled. The median age was 74 years (range 56 to 83), with a median serum PSA at entry of 4.4 ng/mL (range 0.8 to 24.9). No serum PSA responses were observed, and 37% of patients had PSA progression. The median time to progression was not reached. Toxicity was mild, with 1 patient discontinuing therapy because of diarrhea. Significant elevations of plasma lycopene were noted at 3 months and then appeared to plateau for all six dose levels. The plasma levels for doses between 15 and 90 mg/day were similar, with additional elevation only at 120 mg/day. CONCLUSIONS: Lycopene supplementation in men with biochemically relapsed prostate cancer is safe and well tolerated. The plasma levels of lycopene were similar for a wide dose range (15 to 90 mg/day) and plateaued by 3 months. Lycopene supplementation at the doses used in this study did not result in any discernible response in serum PSA.

Adenocarcinoma↗
PubMed2006

Confidence intervals and survival estimates: a systematic review of 3 oncology journals.

PURPOSE: Kaplan-Meier methods generate an estimate of survival when follow-up is less than complete. Confidence intervals (CI) provide a range of values that is likely to contain the true result. We hypothesized that reporting of CI around survival estimates is not uniform. METHODS: We searched all articles in randomly selected issues of Journal of Clinical Oncology (JCO), Cancer, and International Journal of Radiation Oncology Biology, and Physics (IJROBP) years 1999, 2001, and 2004. Articles reporting overall or median survival were reviewed to determine if CI were reported in text or graphical form. Data regarding disease site, intervention, study size, and type of study were collected. RESULTS: A total of 313 articles reported overall or median survival from 35 issues of the 3 journals (IJROBP 115, JCO 132, Cancer 66). CI were reported in 97/313 (31.0%) articles reviewed. CI reporting was more common in prospective clinical trials (38%) than retrospective reviews (25%), P = 0.018. If patients were treated with chemotherapy the article was more likely to report CI (no chemo 20% versus chemo 40%; P = 0.001). CI reporting varied with journal (IJROBP 20%, Cancer 29%, JCO 42%, P = 0.001). CI reporting increased according to year of publication (25% in 1999, 27% in 2001, and 41% in 2004, P = 0.03). CONCLUSION: A majority of studies in major oncology journals do not report CI with survival estimates. The likelihood of reporting CI is associated with study type (prospective versus retrospective), use of chemotherapy, journal, and year of publication.

Confidence Intervals↗
PubMed2006

Update on brachytherapy in localized prostate cancer: the importance of dosimetry.

PURPOSE OF REVIEW: Prostate brachytherapy has become a common treatment modality for clinical localized adenocarcinoma of the prostate. This is the result of prostate screening and improved technology that currently allows for an outpatient procedure that generally can be accomplished in 1-2 h. The modern technique of prostate brachytherapy includes three components, (1) treatment planning, (2) placement of the sources and (3) an evaluation of the implant quality. In this review, we will focus on the importance of dosimetric quantifiers in predicting freedom from biochemical recurrence. RECENT FINDINGS: A number of dosimetric quantifiers have been described. These include D90 (dose that covers 90% of the prostate volume) and V100 (fractional volume of the prostate that receives 100% of the prescription dose). The data from four recently reported series are reviewed. Each series looks at various dosimetric cutpoints that predict for freedom from biochemical recurrence making a definitive statement difficult. All series observe a relationship between freedom from biochemical recurrence and one or both of these dosimetric quantifiers. SUMMARY: It is clear that a dose-response relationship exists following treatment with prostate brachytherapy; in other words, dosimetry matters and poor dosimetry will result in fewer men being cured. The lack of consistency in the reports to date precludes any definitive statements about what constitutes a "good" compared with a "bad" implant. Further prospective data from multi-center trials are required.

Brachytherapy↗
PubMed2005

A phase II study of external beam radiotherapy combined with permanent source brachytherapy for intermediate-risk, clinically localized adenocarcinoma of the prostate: preliminary results of RTOG P-0019.

PURPOSE: To estimate the rate of acute and late Grade 3-5 genitourinary and gastrointestinal toxicity after treatment with external beam radiotherapy and permanent source brachytherapy in a multi-institutional, cooperative group setting. METHODS AND MATERIALS: All patients were treated with external beam radiotherapy (45 Gy in 25 fractions), followed 2-6 weeks later by an interstitial implant using 125I to deliver an additional 108 Gy. Late genitourinary toxicity was graded according to the Common Toxicity Criteria Version 2.0, and the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late radiation morbidity scoring system was used for all other toxicity. RESULTS: A total of 138 patients from 28 institutions were entered on this study. Acute toxicity information was available in 131 patients, and 127 patients were analyzable for late toxicity. Acute Grade 3 toxicity was documented in 10 of 131 patients (7.6%). No Grade 4 or 5 acute toxicity has been observed. The 18-month month estimate of late Grade 3 genitourinary and gastrointestinal toxicity was 3.3% (95% confidence interval, 0.1-6.5). No late Grade 4 or 5 toxicity has been observed. CONCLUSIONS: The acute and late morbidity observed in this multi-institutional, cooperative group study is consistent with previous reports from single institutions with significant prostate brachytherapy experience.

Adenocarcinoma↗
PubMed2005

Health-related quality of life in men receiving prostate brachytherapy on RTOG 98-05.

PURPOSE: To prospectively assess health-related quality of life (HRQOL) during the first year after treatment with prostate brachytherapy (PB) alone for T1c-2a prostate cancer. MATERIALS AND METHODS: Ninety-eight patients from 24 institutions were eligible and properly entered on this study. All patients were treated with PB alone using I-125 (Oncura Model 6711). The prescription dose was 145 Gy. Three separate health-related quality of life questionnaires (HRQOL) (Functional Assessment of Cancer Therapy-Prostate [FACT-P], Sexual Adjustment Questionnaire [SAQ], and International Prostate Symptom Score [IPSS]) were self-administered before and after PB (baseline; 3, 6, 9, and 12 months after PB). The standard error of the mean (SEM) was used to analyze changes in HRQOL scores over time. Patients who improved greater than the SEM were categorized as improved; patients that declined greater than the SEM were categorized as declined; patients were otherwise categorized as stable. All changes are measured using the pretreatment HRQOL score as baseline. RESULTS: The percentage of men who reported the ability to have an erection decreased from 73% at baseline (65% unassisted, 8% assisted) to 57% at 1 year (36% unassisted, 21% assisted). The rate of urinary incontinence increased to 14% at 6 months but had decreased to 1% at the 12-month follow-up. At 1 year after PB, 80% of men reported decreased sexual functioning according to SAQ scores. More than 60% of men reported decreased urinary function at 12 months compared with baseline. CONCLUSIONS: This article represents the first prospective, multi-institutional study of HRQOL in men treated with PB and demonstrates that patients undergoing PB have a very high overall HRQOL. The rate of incontinence by 1 year after PB is low, but many patients continue to have obstructive symptoms at 1 year. Although 78% of 1-year respondents state that they can achieve an erection with or without assistance, almost 50% report a decrease in sexual function.

Aged↗
PubMed2005

Is NNT AOK?

Explore the source record for details and available documents.

Androgen Antagonists↗
PubMed2005

Dosimetry and cancer control after low-dose-rate prostate brachytherapy.

PURPOSE: To describe the relationship between two commonly used dosimetric quantifiers (dose received by 90% of the prostate [D(90)] and volume receiving 100% of dose [V(100)]) and biochemical disease-free survival (bDFS) in a cohort of men treated with low-dose-rate prostate brachytherapy (LDRPB). METHODS AND MATERIALS: The information in this report concerned the first 63 men treated with LDRPB alone at our institution between September 1997 and September 1998. All men had histologically confirmed, clinically localized prostate cancer. All men were treated with(125)I. The prescription dose was 144 Gy according to the Task Group 43 formalism. LDRPB was performed jointly by a radiation oncologist and urologist. Dosimetric quantifiers (D(90), V(100)) were calculated from a CT scan performed 1 month after LDRPB. Biochemical recurrence was defined according to the American Society for Therapeutic Radiology and Oncology consensus definition. Biochemical relapse-free survival (bRFS) was estimated using the product-limit method. D(90) and V(100) were examined as putative covariates for bRFS using the proportional hazards regression method. All p values are two-sided. RESULTS: The median follow-up for the entire cohort was 62 months. The median D(90) was 122 Gy (range, 57-171Gy), and in 16 (25%) of 63 patients, the calculated D(90) was >140 Gy. The median V(100) was 81% (range, 51-97%). Nine men developed evidence of biochemical relapse at a median of 19 months (range, 6-38 months). The 5-year estimate of bRFS was 85% (95% confidence interval, 80-90%). The 5-year estimates of bRFS according to D(90) were as follows: D(90) > or =140 Gy, 86%; D(90) <140 Gy, 84% (p = not statistically significant). No threshold value of D(90) was predictive of the 5-year estimates of bRFS until the D(90) was <80 Gy (D(90) > or =80 Gy, 89%; D(90) <80 Gy, 50%; p = 0.02). The 5-year estimates of bRFS according to V(100) were as follows: V(100) > or =85%, 87%; V(100) <85%, 84% (p = not statistically significant). No threshold value of V(100) was predictive of the 5-year estimates of BRFS unless the dosimetry was particularly poor. The 5-year BRFS was 89% if the V(100) was > or =65% compared with 40% if the V(100) was <65% (p = 0.006). CONCLUSION: The dosimetric or quantifiers described in this report did not predict for bRFS after LDRPB unless the dosimetry was very poor. This finding is not in complete agreement with those of previous reports. Possible reasons for this observation are (1) the study in underpowered, (2) inherent measurement error, (3) dosimetric quantifiers are poor surrogates of the dose received by the cancer, and (4) length of follow-up. Additional work in the area of quality assessment after LDRPB is required.

Aged↗
PubMed2005

Dosimetric quantifiers for low-dose-rate prostate brachytherapy: is V(100) superior to D(90)?

PURPOSE: The purpose of the present report is to describe the relationship between two dosimetric quantifiers (V(100) and D(90)) and freedom from biochemical recurrence (FFBR) in a cohort of men treated with low-dose-rate prostate brachytherapy (LDRPB) alone. METHODS AND MATERIALS: One hundred three men were treated with LDRPB alone between September 1997 and December 1999. All men had histologically confirmed clinically localized prostate cancer. Fifty-nine percent of the cohort had low-risk disease (defined as PSA<10, Gleason <7, and T stage /=10, Gleason>/=7, or T stage T2b). The prescription dose was 144Gy according to the Task Group 43 formalism. LDRPB was performed jointly by a radiation oncologist and a urologist. Dosimetric quantifiers (D(90), V(100)) were calculated from a CT scan performed 1 month after LDRPB. Biochemical recurrence was defined according to the ASTRO Consensus Definition. FFBR was estimated using the product-limit method. Disease-specific and treatment variables were examined as putative covariates for FFBR using the proportional hazards regression method. Univariate and multivariate methods were used. All p values are two sided. RESULTS: The median followup for the entire cohort is 61 months. The median followup of patients at risk for biochemical failure is 66 months. The median D(90) is 129Gy (range 47-221Gy), and the median V(100) is 86% (range 51-99%). Thirteen men have developed evidence of biochemical relapse at a median of 25 months (range 6-42 months). The 5-year estimate of FFBR for the entire cohort is 87% (95% CI 80-94%). On univariate analysis, disease-specific variables found to be significantly associated with FFBR included pretreatment PSA and percent positive biopsies. When considered as a continuous variable, each of the dosimetric quantifiers was associated with FFBR (V(100): p=0.007; D(90): p=0.05). D'Amico risk group classification is highly predictive of FFBR after LDRPB (HR 5.68, p=0.003). Multivariate analysis indicated that each dosimetric quantifier was independently associated with FFBR, but due to the high degree of correlation (Pearson correlation coefficient 0.94, p<0.0001) between the dosimetric quantifiers both could not be included simultaneously in the model. In the two models explored, V(100) was at least as good as D(90) in predicting FFBR. CONCLUSIONS: Dosimetric quantifiers (V(100) and D(90)) are independent predictors of FFBR after treatment with LDRPB alone. In our experience, V(100) seems to be at least equivalent (and perhaps superior) to D(90) for predicting FFBR.

Aged↗
PubMed2004

Cancer control after low-dose-rate prostate brachytherapy performed by a multidisciplinary team with no previous prostate brachytherapy experience.

OBJECTIVES: To describe the biochemical disease-free survival observed in the first cohort men treated by a multidisciplinary team of clinicians with no previous experience in low-dose-rate prostate brachytherapy (LDRPB). METHODS: The information in this report concerns the first 63 men treated with LDRPB alone at our institution between September 1997 and September 1998. All men had histologically confirmed, clinically localized prostate cancer. All men were treated with iodine 125 according to published methods. The prescription dose was 144 Gy according to the Task Group 43 formalism. LDRPB was performed jointly by a radiation oncologist and urologist. Three definitions of biochemical recurrence were used: the American Society for Therapeutic Radiology and Oncology consensus definition; prostate-specific antigen level greater than 0.4 ng/mL at last follow-up; and prostate-specific antigen level greater than 0.2 ng/mL at last follow-up. Biochemical relapse-free survival was estimated using the product-limit method. Putative covariates for biochemical relapse-free survival were examined using the proportional hazards regression model. All P values are two-sided. RESULTS: The median follow-up for the entire cohort was 62 months. Of the 63 men, 45 (71%) had more than 60 months of follow-up. The median pretreatment prostate-specific antigen level was 6.68 ng/mL (range 1.1 to 23), and most men (44 of 63; 70%) had nonpalpable disease. The institutionally assigned Gleason score was less than 7 in 54 men (86%). Nine men developed evidence of biochemical relapse at a median of 19 months (range 6 to 38). The 5-year estimate of biochemical relapse-free survival was 85% (95% confidence interval 80% to 90%), 80% (95% confidence interval 74% to 86%), and 70% (95% confidence interval 64% to 76%) according to the three definitions given above. CONCLUSIONS: The biochemical results achieved in the first cohort of men treated with LDRPB by a previously inexperienced multidisciplinary team of clinicians are similar to the results reported from centers with extensive LDRPB experience.

Aged↗
PubMed2004

Permanent prostate brachytherapy: the significance of postimplant dosimetry.

Recent developments in imaging science and treatment-planning software allow for accurate postimplant dosimetric assessment in all patients after prostate brachytherapy. This article reviews the available data correlating cancer control and morbidity with dosimetric quantifiers obtained from postimplant dosimetric assessment after prostate brachytherapy. Continued collection of dosimetric data in patients treated with prostate brachytherapy will allow for further refinements in the technique, leading to continued high rates of cure with increasingly lower rates of morbidity.

Journal Article↗