Stability of small carbon-nitride heterofullerenes

Carbon nitride nanostructures have been produced by the arc-discharge technique and analyzed by mass spectrometry. A series of structured peaks in the region of masses from 480 up to 600 suggests the existence of heterofullerenes C(n-x)Nx(40 < or = n < or = 50). The structure and stability of these small fullerenes were theoretically investigated by quantum chemical calculations. The obtained heats of formation indicate that C(n) molecules stabilize upon nitrogen substitution. Two C(n-x)Nx cages are quite stable, with heats of formation per atom approaching that of C60. These molecules could be the seeds of onion-like structures seen in CN materials [Phys. Rev. Lett. 87, 225503 (2001)]].

Predicting prostate specific antigen outcome preoperatively in the prostate specific antigen era

PURPOSE

We evaluated the ability of previously defined risk groups to predict prostate specific antigen (PSA) outcome 10 years after radical prostatectomy in patients diagnosed with clinically localized prostate cancer during the PSA era.

MATERIALS AND METHODS

Between 1989 and 2000, 2,127 men with clinically localized prostate cancer underwent radical prostatectomy, including 1,027 at Hospital of the University of Pennsylvania (study cohort) and 1,100 at Brigham and Women's Hospital (validation cohort). Cox regression analysis was done to calculate the relative risk of PSA failure with the 95% confidence interval (CI) in patients at intermediate and high versus low risk. The Kaplan-Meier actuarial method was used to estimate PSA outcome 10 years after radical prostatectomy.

RESULTS

Compared with low risk patients (stages T1c to 2a disease, PSA 10 ng./ml. or less and Gleason score 6 or less) the relative risk of PSA failure in those at intermediate (stage T2b disease or PSA greater than 10 to 20 ng./ml. or less, or Gleason score 7) and high (stage T2c disease, or PSA greater than 20 ng./ml. or Gleason score 8 or greater) risk was 3.8 (95% CI 2.6 to 5.7) and 9.6 (95% CI 6.6 to 13.9) in the study cohort, and 3.3 (95% CI 2.3 to 4.8) and 6.3 (95% CI 4.3 to 9.4) in the validation cohort. The 10-year PSA failure-free survival rate in the 1,020 patients in the low, 693 in the intermediate and 414 in the high risk groups was 83%, 46% and 29%, respectively (p <0.0001).

CONCLUSIONS

Based on 10-year actuarial estimates of PSA outcome after radical prostatectomy 3 groups of patients were identified using preoperative PSA, biopsy Gleason score and 1992 clinical T category.

Emotion knowledge in economically disadvantaged children: self-regulatory antecedents and relations to social difficulties and withdrawal

We examined the relations of verbal ability and self-regulation in preschool to emotion knowledge in first grade, and concurrent relations between emotion knowledge and indexes of social functioning in 143 children from low-income families. After controlling for children's verbal ability in preschool, teacher reports of attentional control and caregiver reports of behavioral control in preschool predicted children's emotion expression knowledge and emotion situation knowledge 2 years later. After controlling for verbal ability and attentional and behavioral control, children's emotion knowledge predicted concurrent teacher-reported social problems and social withdrawal. Results suggest that low levels of emotion knowledge co-occur with many important aspects of children's early social adaptation.

Estimating the impact on prostate cancer mortality of incorporating prostate-specific antigen testing into screening

OBJECTIVES

Whether early detection using prostate-specific antigen (PSA) and digital rectal examination (DRE) compared with DRE alone will reduce prostate cancer mortality awaits the results of ongoing prospective randomized trials. However, the impact that early detection could have on prostate cancer-specific survival can be estimated by assuming that PSA failure after radical prostatectomy (RP) will translate into death from prostate cancer.

METHODS

The study population consisted of 1274 men with clinically localized prostate cancer who underwent RP in Boston, Massachusetts or Philadelphia, Pennsylvania between 1989 and 2000 and had a preoperative PSA level greater than 4 but not more than 10 ng/mL. The primary endpoint was actuarial freedom from PSA failure (defined as PSA outcome).

RESULTS

The relative risk of PSA failure after RP for patients diagnosed with a PSA of greater than 4 to 5, 5 to 6, 6 to 7, or 7 to 8 ng/mL compared with greater than 8 up to 10 ng/mL was 0.3 (95% confidence interval [CI] 0.2 to 0.5), 0.5 (95% CI 0.4 to 0.8), 0.6 (95% CI 0.4 to 0.9), or 0.9 (95% CI 0.6 to 1.3), respectively. On the basis of the estimates of the 5-year PSA outcome, patients with a biopsy Gleason score of 5 or 6 (781 of 1274; 61%) consistently benefited from RP performed when the PSA at diagnosis was greater than 4 to 7 ng/mL compared with greater than 8 to 10 ng/mL (93% versus 78%, P <0.0001). A benefit to early detection was not found for the vast majority (266 of 312; 88%) of patients who had a biopsy Gleason score of 7 or higher.

CONCLUSIONS

Early detection using both PSA and DRE-based screening may benefit men who present with biopsy Gleason score 5 or 6 prostate cancer and a PSA level greater than 4 to 7 ng/mL compared with greater than 8 up to 10 ng/mL. This finding awaits validation from ongoing prospective randomized trials.

Family structure and the externalizing behavior of children from economically disadvantaged families

This study examined the relations among family structure, caregiver relationship history, aspects of environmental adversity, and teacher reports about the externalizing behaviors of 6- and 7-year-old children from economically disadvantaged families. Family structure contrasted intact families, stepfamilies, single-parent families, and cohabiting families. Problem behaviors were more frequent for children from unmarried families than from married families and were more frequent for boys than for girls from cohabiting families. Relationship history reduced the effects for family structure. Children's adjustment varied with both the current status and past stability of caregiver intimate relationships for disadvantaged families.

The clinical utility of the percent of positive prostate biopsies in predicting biochemical outcome following external-beam radiation therapy for patients with clinically localized prostate cancer

PURPOSE

An investigation was performed of the clinical utility of the percent of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome following external-beam radiation therapy (RT) for men with PSA-detected or clinically palpable prostate cancer.

METHODS AND MATERIALS

A Cox regression multivariable analysis was used to determine whether the percent of positive prostate biopsies provided clinically relevant information about PSA outcome following external beam RT in 473 men while accounting for the previously established risk groups based on the pretreatment PSA level, biopsy Gleason score, and the 1992 American Joint Commission on Cancer (AJCC) clinical T stage.

RESULTS

Controlling for the known prognostic factors, the percent of positive prostate biopsies added clinically significant information (p = 0.02) regarding time to PSA failure following RT. Specifically, 76% of the patients in the intermediate risk group (1992 AJCC T(2b) or biopsy Gleason 7 or PSA > 10 ng/mL and < or = 20 ng/mL) could be classified into either an 30% or 85% 5-year PSA control cohort using the preoperative prostate biopsy data.

CONCLUSION

The previously validated stratification of PSA outcome following radical prostatectomy (RP) using the percent of positive prostate biopsies in intermediate-risk patients is also clinically significant for men treated with external beam RT. The percent positive prostate biopsies should be considered in conjunction with the PSA level, biopsy Gleason score, and 1992 AJCC clinical T stage when counseling patients with newly diagnosed and clinically localized prostate cancer about PSA outcome following RP or external beam RT.

Optimizing patient selection for prostate monotherapy

PURPOSE

Patients at low risk for prostate-specific antigen (PSA) failure following definitive local therapy are those with PSA of 10 or less, biopsy Gleason Score of 6 or less, and 1992 American Joint Committee on Cancer (AJCC) clinical Stage T1c or T2a. However, low-risk patients managed with radical prostatectomy and found to have prostatectomy Gleason score > or = 3+4 have a less favorable PSA outcome when compared to patients with prostatectomy Gleason score < or = 3+3. This study was performed to determine whether the percentage of positive prostate biopsy cores could predict upgrading from a biopsy Gleason score of 6 or less to a prostatectomy Gleason score > or = 3+4 in low-risk patients to optimize selection for prostate only radiation therapy.

METHODS AND MATERIALS

Concordance testing of the biopsy Gleason score and the primary and secondary prostatectomy Gleason grades was performed in 427 prostate cancer patients treated with radical prostatectomy and at low risk for PSA failure. Logistic regression multivariable analysis was performed to test the ability of the established prognostic factors and the percentage of positive prostate biopsies (<34%, 34-50%, >50%) to predict for upgrading from biopsy Gleason score of 6 or less prostatectomy Gleason score > or = 3+4. PSA failure-free survival was reported using the actuarial method of Kaplan and Meier and comparisons were made using a log-rank test.

RESULTS

Twenty-nine percent of the 427 study patients were upgraded from a biopsy Gleason score of 6 or less to a prostatectomy Gleason score > or = 3+4. The presence of greater than 50% positive biopsies was the only significant factor for predicting the upgrading from biopsy Gleason score of 6 or less to prostatectomy Gleason score > or = 3+4 on logistic regression multivariable analysis with the variables treated as continuous and categorical. Specifically, upgrading occurred in 26% vs. 59% of patients with 50% or less vs. greater than 50% positive biopsies, respectively. This translated into a 5-year PSA failure-free survival which was significantly higher (92% vs. 62%, p = 0.00001) for men with 50% or less vs. greater than 50% positive prostate biopsies, respectively.

CONCLUSION

The presence of greater than 50% positive biopsies was associated with higher rates of pathologic upgrading which translated into lower 5-year PSA failure-free survival following radical prostatectomy (RP). Therefore, the percentage of positive biopsies may be useful in optimizing the selection of low-risk patients for prostate only radiation therapy such as external beam radiation or implant monotherapy.

Clinical utility of percent-positive prostate biopsies in predicting biochemical outcome after radical prostatectomy or external-beam radiation therapy for patients with clinically localized prostate cancer

BACKGROUND AND PURPOSE

The clinical utility of the percentage of positive prostate biopsies in predicting prostate specific antigen (PSA) outcome after radical prostatectomy (RP) or external-beam radiation therapy (EBRT) for men with PSA-detected or palpable prostate cancer is not established.

METHODS

A Cox regression multivariable analysis was used to determine whether percent-positive prostate biopsies provided clinically relevant information about PSA outcome after RP in 960 men, while accounting for the previously established risk groups based on the pretreatment PSA concentration biopsy Gleason score, and the 1992 American Joint Commission on Cancer clinical T stage.

RESULTS

In the intermediate-risk group, 80% of the patients (stage T(2b) or biopsy Gleason 7 or PSA 10-20 ng/mL) could be classified into either an 11% or an 86% 4-year PSA control cohort using the preoperative prostate biopsy data. These findings were validated using an independent surgical (N = 823) and radiation (N = 473) data set. Percent-positive prostate biopsies added clinically significant information regarding time to PSA failure after RP.

CONCLUSIONS

The percentage of positive prostate biopsies should be considered in conjunction with the PSA level, biopsy Gleason score, and clinical T stage when counseling patients with newly diagnosed and clinically localized prostate cancer about PSA outcome after RP or EBRT.

Emotion knowledge as a predictor of social behavior and academic competence in children at risk

Following leads from differential emotions theory and empirical research, we evaluated an index of emotion knowledge as a long-term predictor of positive and negative social behavior and academic competence in a sample of children from economically disadvantaged families (N = 72). The index of emotion knowledge represents the child's ability to recognize and label emotion expressions. We administered control and predictor measures when the children were 5 years old and obtained criterion data at age 9. After controlling for verbal ability and temperament, our index of emotion knowledge predicted aggregate indices of positive and negative social behavior and academic competence. Path analysis showed that emotion knowledge mediated the effect of verbal ability on academic competence. We argue that the ability to detect and label emotion cues facilitates positive social interactions and that a deficit in this ability contributes to behavioral and learning problems. Our findings have implications for primary prevention.

Investigating the clinical utility of the percent of positive prostate biopsies in predicting PSA outcome following local therapy for patients with clinically localized prostate cancer

The clinical utility of the percent of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome following radical prostatectomy (RP), or external beam radiation therapy (RT), for men with PSA detected, or clinically palpable prostate cancer was investigated. After accounting for the established prognostic significance of the PSA level, biopsy Gleason score and the clinical T-stage, the percent of positive prostate biopsies added clinically significant information regarding time to PSA failure following RP. These findings were validated in the intermediate risk patients using an independent surgical and radiation data set. Prostate Cancer and Prostatic Diseases (2000) 3, 259-264

Biochemical outcome following external beam radiation therapy with or without androgen suppression therapy for clinically localized prostate cancer

CONTEXT

Combined treatment using radiation therapy (RT) and androgen suppression therapy (AST) is used to treat men with clinically localized adenocarcinoma of the prostate, but outcome using this combined therapy compared with RT alone is not known.

OBJECTIVE

To determine the relative efficacy of RT plus AST vs RT alone among men with clinically localized prostate cancer.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study of 1586 men with prostate cancer who were treated between January 1989 and August 1999 using 3-dimensional conformal RT with (n = 276) or without (n = 1310) 6 months of AST.

MAIN OUTCOME MEASURE

Relative risk (RR) of prostate-specific antigen (PSA) failure (defined according to the American Society for Therapeutic Radiology and Oncology consensus statement), by treatment and high-, intermediate-, or low-risk group based on serum PSA level, biopsy Gleason score, and 1992 American Joint Commission on Cancer clinical tumor category.

RESULTS

Estimates of 5-year PSA outcome after RT with or without AST were not statistically different among low-risk patients (P =.09), whereas intermediate- and high-risk patients treated with RT plus AST had significantly better outcomes than those treated with RT alone (P<.001 and =.009, respectively). The RR of PSA failure in low-risk patients treated with RT plus AST was 0.5 (95% confidence interval [CI], 0.3-1.1) compared with patients treated with RT alone. The RRs of PSA failure in intermediate-risk and high-risk patients treated with RT plus AST compared with RT alone were 0.2 (95% CI, 0. 1-0.3) and 0.4 (95% CI, 0.2-0.8), respectively.

CONCLUSIONS

Our data suggest a significant benefit in 5-year PSA outcomes for men with clinically localized prostate cancer in intermediate- and high-risk groups treated with RT plus AST vs those treated with RT alone. Results from prospective randomized trials currently under way are needed to validate these findings. JAMA. 2000;284:1280-1283

Endorectal magnetic resonance imaging as a predictor of biochemical outcome after radical prostatectomy in men with clinically localized prostate cancer

PURPOSE

Endorectal magnetic resonance imaging (MRI) of the prostate is sometimes performed before radical prostatectomy but to our knowledge its role for predicting outcome after radical prostatectomy is not yet established. We evaluated the clinical usefulness of endorectal MRI for predicting time to prostate specific antigen (PSA) failure after radical prostatectomy in 1,025 consecutive men with clinically localized or PSA detected prostate cancer. Our analysis controlled for PSA level, biopsy Gleason score, clinical T stage and percent of positive biopsies.

MATERIALS AND METHODS

Using Cox regression analysis we prospectively assessed time to PSA failure to determine the role of endorectal MRI in predicting PSA outcome after radical prostatectomy at our institution, where an expert prostate magnetic resonance radiologist is available. The main outcome measure was actuarial freedom from PSA failure.

RESULTS

Endorectal MRI did not add clinically meaningful information in 834 of our 1,025 cases (81%) after accounting for the prognostic value of PSA, biopsy Gleason score, clinical T stage and percent of positive biopsies. However, this modality provided a clinically and statistically relevant stratification of 5-year PSA outcome in the remaining 191 patients at intermediate risk based on established prognostic factors. Specifically when endorectal MRI was interpreted as indicating extracapsular versus organ confined disease the relative risk of PSA failure was 3.6 (95% confidence interval 2.0 to 6.3), and 5-year actuarial freedom from PSA failure was 33% versus 72% (p <0.0001).

CONCLUSIONS

Despite expert radiological interpretation endorectal MRI had potential clinical value in less than 20% of the cases in our study after accounting for established prognostic factors. While further study of the value of this modality for predicting clinical outcome after radical prostatectomy should be performed in this select cohort, routine use of endorectal MRI cannot be justified based on these data.

Quest for fire: seeking the source of pathogenic oxygen radicals in atherosclerosis

There is an accumulating body evidence that atherosclerosis is either caused by or accompanied by oxidative events in the vessel wall. These oxidative events have been implicated in proatherogenic modification of proteins, alteration of gene expression, promotion of inflammation, remodeling of vessels, and perturbations of vascular tone. This body of literature has led to a dogma that oxidation is a prerequisite for the atherosclerotic process. In particular, oxidation of lipoproteins by activated macrophages in the subintimal space has been postulated to be an important early step in the atherosclerotic process.

Comparing prostate specific antigen outcomes after different types of radiotherapy management of clinically localized prostate cancer highlights the importance of controlling for established prognostic factors

PURPOSE

We evaluated the impact that the composition of prognostic factors in a patient cohort may have on prostate specific antigen (PSA) outcome following external beam radiation therapy for clinically localized prostate cancer.

MATERIALS AND METHODS

The distribution of PSA, biopsy Gleason score and American Joint Committee on Cancer (AJCC) T stage in men with prostate cancer treated with interstitial plus external beam radiation therapy was used to select a matched cohort who underwent 3-dimensional (D) conformal external beam radiation therapy. We compared PSA outcomes after 3-D conformal external beam radiation therapy in the overall and matched cohorts of 766 and 570 patients, respectively.

RESULTS

Men treated with interstitial plus external beam radiation therapy had a significantly lower rate of PSA greater than 10 to 20 (p = 0. 02) and greater than 20 ng./ml. (p <0.0001), biopsy Gleason score 7 (p = 0.02) and 8 to 10 (p <0.0001), and AJCC stage T2c disease (p <0. 0001). Likewise, these men also had a significantly higher rate of PSA greater than 4 to 10 ng./ml. (p <0.0001), biopsy Gleason score 5 to 6 (p = 0.0001) and AJCC stage T1 disease (p <0.0001) than those who underwent 3-D conformal external beam radiation therapy. The 5-year estimate of PSA failure-free survival after 3-D conformal external beam radiation therapy was 45% versus 67% (p = 0.0007) for all 766 consecutively treated patients and the matched cohort of 570, respectively.

CONCLUSIONS

The composition of prognostic factors in a patient cohort may impact PSA outcome. Therefore, controlling for established prognostic factors is essential when comparing PSA outcome after different forms of radiotherapy for adenocarcinoma of the prostate.

Prostate specific antigen outcome based on the extent of extracapsular extension and margin status in patients with seminal vesicle negative prostate carcinoma of Gleason score < or = 7

BACKGROUND

Early (< or = 2 years) prostate specific antigen (PSA) failure after radical prostatectomy (RP) has been shown to predict for distant failure. After excluding patients with the pathologic predictors of early PSA failure, an analysis of PSA failure free (bNED) survival was performed to identify patients who may benefit from the use of postprostatectomy radiation therapy (RT).

METHODS

Of 1,028 patients treated with RP for clinically localized prostate carcinoma between 1989 and 1999, 862 (84%) had either organ confined (OC), specimen confined (SC), or margin positive disease with negative seminal vesicles (SV) and a prostatectomy Gleason score < or = 7. A Cox regression multivariate analysis was performed in these patients evaluating the ability of the extent of extracapsular extension (ECE) (into but not through the capsule, SC focal ECE, SC established ECE, margin positive) and prostatectomy Gleason score (2-6 vs. 7) to predict time to postoperative PSA failure.

RESULTS

SC focal ECE (P = 0.0017), SC established ECE (P < 0.0001), and margin positive disease (P < 0.0001) were significant predictors of time to postoperative PSA failure, whereas prostatectomy Gleason score and disease extending into but not through the capsule were not. Five-year bNED rates were 90%, 88%, 69%, 45%, and 33% for patients with OC, into but not through capsule, SC focal ECE, SC established ECE, and margin positive prostate carcinoma, respectively.

CONCLUSIONS

Patients with SC ECE or margin positive prostate carcinoma and a prostatectomy Gleason score < or = 7 with no evidence of SV invasion may benefit from adjuvant postoperative RT.

Clinical utility of the percentage of positive prostate biopsies in defining biochemical outcome after radical prostatectomy for patients with clinically localized prostate cancer

PURPOSE

To determine the clinical utility of the percentage of positive prostate biopsies in predicting prostate-specific antigen (PSA) outcome after radical prostatectomy (RP) for men with PSA-detected or clinically palpable prostate cancer.

METHODS

A Cox regression multivariable analysis was used to determine whether the percentage of positive prostate biopsies provided clinically relevant information about PSA outcome after RP in 960 men while accounting for the previously established risk groups that are defined according to pretreatment PSA level, biopsy Gleason score, and the 1992 American Joint Committee on Cancer (AJCC) clinical T stage. The findings were then tested using an independent surgical database that included data for 823 men.

RESULTS

Controlling for the known prognostic factors, the percentage of positive prostate biopsies added clinically significant information (P <.0001) regarding time to PSA failure after RP. Specifically, 80% of the patients in the intermediate-risk group (1992 AJCC T2b, or biopsy Gleason 7 or PSA > 10 ng/mL and </= 20 ng/mL) could be classified into either an 11% or 86% 4-year PSA control cohort using the preoperative prostate biopsy data. These findings were validated in the intermediate-risk patients using an independent surgical data set.

CONCLUSION

The validated stratification of PSA outcome after RP using the percentage of positive prostate biopsies in intermediate-risk patients is clinically significant. This information can be used to identify men with newly diagnosed and clinically localized prostate cancer who are at high risk for early (</= 2 years) PSA failure and, therefore, may benefit from the use of adjuvant therapy.

Optimizing patient selection for dose escalation techniques using the prostate-specific antigen level, biopsy gleason score, and clinical T-stage

PURPOSE

Ideal candidates for 3D dose escalation conformal radiation or external beam + implant therapy are identified on the basis of the prostate-specific antigen (PSA) level, biopsy Gleason score, and the 1992 American Joint Commission Cancer (AJCC) clinical T-stage.

METHODS AND MATERIALS

The pathologic findings of 1742 men with clinical stage T1c,2 prostate cancer managed with a radical prostatectomy (RP) between 1990 and 1998 were subjected to a logistic regression multivariable analysis. The endpoints examined included pathologic organ-confined (OC), specimen-confined (SC), and margin (M) or seminal vesicle (SV) positive disease. SC disease was defined as extracapsular extension (ECE) with a negative surgical margin. The clinical factors tested included PSA level, biopsy Gleason score, and the 1992 AJCC clinical T-stage. PSA failure-free (bNED) survival was calculated according to the method of Kaplan and Meier.

RESULTS

Significant negative predictors of pathologic OC-disease or positive predictors of M+ or SV+ disease included a PSA > 10 ng/ml (p<0.0001), biopsy Gleason score < or =7 (p< or =0.0004), and > or =T2b disease (p< or =0.03). Only biopsy Gleason score 7 (p = 0.0006) and PSA 10-15 ng/ml (p = 0.04) were significant predictors of SC disease. The estimates of 5-year bNED survival were 80%, 62%, and 35% (p<0.0001) for patients having a low, intermediate, or high likelihood of having M+ or SV+ disease respectively.

CONCLUSIONS

Patients most likely to derive a survival benefit from the improved local control possible using dose escalation techniques were those who had both a low risk of having occult micrometastatic disease (<25% M+ or SV+) and a reasonable likelihood of remaining disease-free after RP (>50% 5-year bNED). These patients included those having T1c, 2a, PSA > 10-15 ng/ml, and biopsy Gleason < or =6 or T1c, 2a, 2b, PSA < or =10 ng/ml, and biopsy Gleason < or =7 prostate cancer.

The impact of the biopsy Gleason score on PSA outcome for prostate cancer patients with PSA < or = 10 ng/ml and T1c,2a: implications for patient selection for prostate-only therapy

PURPOSE

This study was performed to determine the ability of the biopsy Gleason score, prostate-specific antigen (PSA) level, and the 1992 American Joint Commission on Cancer (AJCC) clinical T-stage for predicting time to postoperative PSA failure for patients with a PSA < or =10 ng/ml and T1c or T2a disease. Specific attention is given to the patient subgroup with biopsy Gleason 3 + 4 vs. 4 + 3.

METHODS AND MATERIALS

A concordance map of the biopsy and prostatectomy Gleason grades and a clinical-pathologic correlation of the PSA, biopsy Gleason score, and 1992 AJCC T-stage and pathologic stage were performed. A Cox regression multivariable analysis was used to evaluate the ability of the biopsy Gleason score, PSA, and 1992 AJCC T-stage to predict time to PSA failure for 457 men managed with a radical prostatectomy (RP).

RESULTS

The absence of prostatectomy Gleason grade 4 or 5 disease was noted in 71%, 50%, and 11% of patients with biopsy Gleason score 2-6, 3 + 4, and > or =4 + 3 disease respectively while pathologic evidence of seminal vesicle invasion was noted in 2%, 4%, and 17% of these patients respectively. Estimates of 5-year PSA failure-free survival rates were not statistically different for patients with biopsy Gleason score 2-6 vs. 3 + 4 (79% vs. 81%; p = 0.93), but were significantly different for patients having biopsy Gleason score 2-6 vs. 4 + 3 (79% vs. 62%; p = 0.04) or 2-6 vs. 8-10 (79% vs. 18%; p = 0.0001) prostate cancer.

CONCLUSION

Based on the pathologic stage and PSA control data following RP, patients with biopsy Gleason 3 + 4 disease and PSA < or =10 ng/ml and 1992 AJCC T1c or T2a disease may be suitable candidates for radiation therapy directed at the prostate only.

Clinical predictors of upgrading to Gleason grade 4 or 5 disease at radical prostatectomy: potential implications for patient selection for radiation and androgen suppression therapy

PURPOSE

A survival benefit has been suggested by the Radiation Therapy Oncology Group (RTOG) for the addition of androgen suppression to external beam radiation therapy for patients with locally advanced and high-grade disease. This study was performed to identify clinical factors that predicted high-grade disease at prostatectomy (i.e., Gleason grade 4 or 5) in patients with clinically localized and low-grade disease (i.e., Gleason grades 1-3) at biopsy. These pretreatment factors may allow for the identification of patients likely to derive a survival benefit from the addition of androgen suppression to external beam radiation therapy while awaiting the results of the prospective randomized trials.

METHODS AND MATERIALS

Concordance testing of both the primary and secondary biopsy and prostatectomy Gleason grades was performed in 693 patients with clinical Stage T1c, 2 prostate cancer managed with a radical prostatectomy (RP). For the subset of 420 patients with low-grade disease (i.e., Gleason grade < or =3) a logistic regression multivariable analysis was performed to evaluate the ability of the preoperative prostate-specific antigen (PSA), clinical stage, and ultrasound determined prostate gland volume to predict for upgrading to high-grade disease (i.e., Gleason grade 4 or 5).

RESULTS

Forty percent of men with low-grade disease at biopsy were found to have high-grade disease at RP. Men who have at least a 50% chance of being upgraded from biopsy Gleason grade < or =3 to prostatectomy Gleason grade > or =4 disease included those with prostate gland volumes < or =75 cm3 and a PSA > 20 ng/ml or a PSA >10 and < or =20 and clinical Stage T2b,2c. For men with prostate gland volumes >75 cm3, only those with both PSA > 20 ng/ml and clinical Stage T2b,2c were at a significant risk of upgrading.

CONCLUSION

Until the randomized data become available, clinical factors may be useful in identifying patients with clinically localized prostate cancer who are likely to benefit from combined androgen suppression and external beam radiation therapy.

Radiation safety system of the B-Factory at the Stanford Linear Accelerator Center

The radiation safety system of the B-Factory accelerator facility at the Stanford Linear Accelerator Center is described. The radiation safety system, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system and the radiation containment system. The access control system prevents people from being exposed to the very high radiation levels inside a beamline shielding enclosure. The access control system consists of barriers, a standard entry module at every entrance, and beam stoppers. The radiation containment system prevents people from being exposed to the radiation outside a shielding enclosure due to either normal or abnormal operation. The radiation containment system consists of power limiting devices, shielding, dump and collimator, and an active radiation monitoring system. The inter-related elements for the access control system and radiation containment system, as well as the associated interlock network, are described. The policies and practices used in establishing the radiation safety system are also compared with the regulatory requirements.