Long-Term Outcomes of NRG/RTOG 0126, a Randomized Trial of High Dose (79.2 Gy) vs. Standard Dose (70.2 Gy) Radiation Therapy (RT) for Men with Localized Prostate Cancer

PURPOSE/OBJECTIVE(S)

NRG/RTOG 0126, a phase III trial for men with localized prostate cancer testing whether dose escalation to 79.2 Gy with 3DCRT/IMRT improved overall survival (OS). Long-term results of this trial are presented.

MATERIALS/METHODS

Patients with clinical stage T1b-T2b and either Gleason Score (GS) 2-6 and 10 ≤ PSA < 20 or GS 7 and PSA < 15 were eligible and randomized to receive 79.2 Gy or 70.2 Gy. No previous or concurrent androgen withdrawal therapy was administered. Treatment was delivered with 3DCRT/IMRT to a dose of 79.2 Gy in 44 fractions or 70.2 Gy in 39 fractions to the PTV encompassing the prostate and seminal vesicles. Image guidance was not required. ASTRO and Phoenix definitions were used for biochemical failure (ABF and PBF, respectively). OS was estimated by the Kaplan-Meier method and arms compared with the log-rank test. ABF, PBF, local progression (LP), distant metastases (DM) and time to late GI/GU toxicities were estimated by the cumulative incidence method and arms compared with Gray's test.

RESULTS

One thousand five hundred thirty-two men were randomized, 763 to 79.2 Gy and 769 to 70.2 Gy. 1499 were eligible, 748 and 751 in the 79.2 Gy and 70.2 Gy arms respectively. Median age was 71, 70% had PSA < 10 ng/ml, 84% with GS 7, 57% had T1 disease, and 66% treated with 3D-CRT. Outcomes are shown in the TABLE: . With a median follow up of 12 years, there was no significant difference in OS. There was a statistically significant decrease in the cumulative incidence of ABF, PBF, DM, LP, and salvage therapies in the 79.2 Gy arm. There were significantly higher rates of grade 2+ GI and GU toxicity in the 79.2 Gy arm. There were no statistically significant differences in the rates of grade 3+ GU or GI toxicity between either arm.

CONCLUSION

Long term follow up confirms no improvement in OS with dose escalation in this study population. However, there are significant improvements in ABF, PBF, DM, LP, and need for salvage therapy. Despite the use of more salvage therapy in the low dose arm, dose escalated RT resulted in lower rates of DM, a clinically relevant endpoint. Patients receiving dose escalation do experience a higher rate of grade 2+ GU and GI toxicity but no worse grade 3+ toxicities.

Validation of a Genomic Classifier in the NRG Oncology/RTOG 0521 Phase III Trial of Docetaxel with Androgen Suppression and Radiotherapy for Localized High-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

Decipher is a prognostic genomic classifier (GC) validated in several prospective NRG Oncology Phase III trials. Herein, we validate the GC in pre-treatment biopsy samples for risk stratification in a cohort of high-risk men treated with definitive radiotherapy and androgen suppression with or without docetaxel chemotherapy.

MATERIALS/METHODS

As per a pre-specified and approved NCI analysis plan (Navigator #1061), we obtained available formalin-fixed paraffin-embedded tissue from biopsy specimens from the NRG biobank from patients enrolled on the NRG/RTOG 0521 randomized phase III trial. After central review, the highest-grade tumors were profiled on clinical-grade whole-transcriptome arrays (Veracyte, San Diego, CA) and GC scores were obtained. Pre-specified categorical GC scores, adjusted for archival tissue analysis, were used to define higher (>0.46) and lower (≤0.46) risk groups. The primary objective was to validate the independent prognostic ability of GC for metastasis-free survival (MFS) with Cox multivariable analyses (MVA).

RESULTS

Samples were obtained from 283 consented, evaluable patients with tissue (50% of trial) yielding 183 (65%) GC scores that passed quality metrics, 91 from control and 92 from the interventional arm. Median age was 66 years, median PSA was 19.3 ng/uL (IQR: 8.1-41.4), 81% had clinical stage ≥T2 and 80% had Gleason score ≥8 (47% ≥9). Median GC score was 0.55 (IQR: 0.38-0.78) and overall the arms were balanced for key covariates. With a median follow-up of 9.9 years (IQR: 9.3, 10.7), 67 MFS events including 34 distant metastases (DM) were observed. On MVA, only the GC (per 0.1 unit) was independently associated with MFS (HR 1.12, 95% CI 1.01-1.25) as well as DM (sHR 1.22, 95% CI 1.06-1.41), whereas the 4 pre-defined trial risk groups used for stratification (based on Gleason score, T-stage and PSA), randomization and patient age were not. For categorical GC, on MVA, higher-risk GC patients (65%) had worse DM (sHR 2.82, 95% CI 1.1-7.3) compared to those with lower GC. Cumulative incidence of DM at 10-years was 27% for higher GC vs 9% (95% CI 7-18%) for lower GC. No biomarker-by-treatment interaction with GC and the addition of docetaxel was detected.

CONCLUSION

In pre-treatment biopsy samples from a randomized Phase 3 trial cohort, GC demonstrated its ability to further risk stratify clinically high-risk men demonstrating an independent association of GC score with DM and MFS. High-risk prostate cancer is a heterogeneous disease state and GC can improve risk stratification to help personalize shared decision-making. NRG-GU009/PREDICT-RT (NCT04513717) aims to determine the optimal therapy based on GC score for high-risk prostate cancer.

Individual Patient Data Analysis of 17 Randomized Trials vs. Real-World Data for Men with Localized Prostate Cancer Receiving Radiotherapy

PURPOSE/OBJECTIVE(S)

Prior work has demonstrated poor correlation between the results of randomized controlled trials (RCTs) and real-world evidence (RWD). However, patients enrolled in RCTs are often considered to poorly represent the real-world population. Herein, we utilize multiple large data repositories to determine differences in baseline characteristics and long-term outcomes between patients enrolled in RCTs and RWD that received radiotherapy for localized prostate cancer.

MATERIALS/METHODS

Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) Consortium was leveraged, and 17 phase III randomized trials were included. RWD were accessed through the Staging Collaboration for Cancer of the Prostate (STAR-CAP) cohort, a cohort that is comprised of >60 centers across the United States and Europe. Additionally, RWD was assessed via the Surveillance, Epidemiology, and End Results (SEER) database. MARCAP and STAR-CAP both contain outcomes for distant metastasis (DM), metastasis-free survival (MFS), prostate cancer-specific mortality (PCSM), and overall survival (OS). SEER only contains PCSM and OS. Wilcoxon signed-rank test and chi-square test were used to compare continuous and categorical variables, respectively. Inverse probability of treatment weighting (IPTW) analysis was conducted, balancing for age, PSA, Gleason score, T stage, and treatment year in the three cohorts. Cox and Fine-Gray regression models were used to compare disease outcomes between RCTs vs. RWD.

RESULTS

Data from 10,666 patients from RCTs, 6,530 patients in STAR-CAP, and 117,586 patients in SEER were included. SEER patients were slightly younger (p<0.001, median age 68 (IQR 62-73) than those in RCTs (70, IQR 65-74) and in STAR-CAP (70, IQR 64-74). 10-year OS in RCTs was 65.4%, STAR-CAP 70.2%, SEER 64.1%. OS was superior in STAR-CAP (RCTs as reference; HR 0.91, 95% CI 0.85-0.96, p<0.0001), but there was no significant difference between SEER and RCTs (HR 0.96, 95% CI 0.91-1.02, p = 0.22). 10-year PCSM cumulative incidence was 7.4% in RCTs, 8.1% in STAR-CAP, and 11.0% in SEER. There was no significant difference in PCSM between STAR-CAP RWD and RCTs (HR 0.88, 95% CI 0.78-1.01, p = 0.08), whereas PCSM was worse in SEER than RCTs (HR 1.37, 95% CI 1.21-1.55, p<0.0001). There was no significant difference in DM between STAR-CAP RWD and RCTs (HR 0.93, 95% CI 0.83-1.04, p = 0.2).

CONCLUSION

While baseline differences exist in patients enrolled on localized prostate cancer RCTs and real-world datasets, there were small if any significant relative differences in oncologic outcomes. This provides reassurance that RCT results are generally applicable to patients in routine practice.

Long-Term Follow-Up Analysis of NRG Oncology RTOG 0415: A Randomized Phase III Non-Inferiority Study Comparing Two Fractionation Schedules in Patients with Favorable-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

To assess whether the efficacy of a hypofractionated (H) schedule is no worse than a conventional (C) schedule in men with low-risk prostate cancer.

MATERIALS/METHODS

Accrual began April 2006 and ended in December 2009. 1115 men with favorable-risk prostate cancer were randomly assigned 1:1 to a conventional (C) schedule (73.8 Gy in 41 fractions over 8.2 weeks) or to a hypofractionated (H) schedule (70 Gy in 28 fractions over 5.6 weeks). The trial was designed to establish with 90% power and alpha = 0.05 that (H) results in 5-year disease-free survival (DFS) that is not lower than (C) by more than 7% (hazard ratio (HR) < 1.52). Protocol specified secondary endpoints evaluated for noninferiority include: biochemical recurrence (BR), local progression, disease-specific survival, and overall survival.

RESULTS

One thousand ninety-two protocol eligible men were analyzed: 542 to C and 550 to H. Median follow-up is 12.75 years. Baseline characteristics were not different according to treatment arm. The estimated 12-year DFS is 56.1% (95% CI 51.5, 60.5) in the C arm and 61.8% (57.2, 66.0) in the H arm. The DFS hazard ratio (H/C) is 0.85 (0.71-1.03), confirming non-inferiority (p<0.001). Twelve-year cumulative incidence of biochemical recurrence (BR) was 17.0% (CI 13.8, 20.5) in the C-RT and 9.9% (CI 7.5, 12.6) in the H-RT arm; (HR = 0.56, (0.40-0.78) suggesting improved efficacy with H. Additional pre-specified secondary endpoints were non-inferior Late Grade ≥ 3 GI toxicity is 3.2% (C) vs. 4.4% (H), Relative risk (RR) for H vs. C 1.39 (CI 0.75, 2.55) Late Grade ≥ 3 GU toxicity is 3.4% (C) vs. 4.2% (H), RR = 1.26 (CI 0.69, 2.30).

CONCLUSION

In men with favorable-risk prostate cancer, long-term disease-free survival is non-inferior with 70 Gy in 28 fractions compared to 73.8 Gy in 41 fractions. The risk of BR is reduced with moderate hypofractionation. No differences in late Grade ≥3 GI/GU toxicity were observed between the arms. (ClinicalTrials.gov identifier: NCT00331773).

Non-Redundant Mechanisms of Immune Resistance to Radiotherapy Converge on Innate Immunity

PURPOSE/OBJECTIVE(S)

Despite evidence of preclinical synergy between radiotherapy (RT) and immune checkpoint blockade (ICB), randomized trials of RT/ICB have demonstrated limited benefit in solid tumors. We performed single-cell RNA sequencing (scRNA-seq) and CITE-seq (cellular indexing of transcriptomes and epitopes) to address the discordance between preclinical and clinical data. We hypothesized that multiple orthogonal inhibitory immune pathways restrain the local and systemic efficacy of RT beyond T-cell oriented immune checkpoints.

MATERIALS/METHODS

We used the EO771 syngeneic murine model of breast cancer to characterize the immune tumor microenvironment following RT with or without ICB. RT (16 Gy x 1) was delivered using the X-RAD SmART platform with CT image guidance. Neutralizing antibodies (anti-PD-1/Ly6G/Gr-1/CD47) were delivered by intraperitoneal injections. scRNA-seq analysis were performed by Seurat and BBrowser (BioTuring).

RESULTS

We found that adaptive ICB (anti-PD-1) reprogrammed the immune response to RT by promoting an M1-like interferon-primed state (ISG15, CXCL10) in tumor associated macrophages (TAMs) and by increasing the late recruitment of intratumoral neutrophils. Given that neutrophils may drive resistance to RT in other models, we evaluated the effect of intratumoral neutrophil depletion using anti-Ly6G or anti-Gr-1 on the antitumor efficacy of RT/ICB. Both neutrophil depletion strategies led to enhanced tumor control and improved survival in advanced EO771 tumors compared to RT/ICB alone (P<0.001). In parallel to this approach, we found that TAMs upregulated several innate immune checkpoints including SIRPα in response to RT. Disruption of the SIRPα-CD47 interaction by anti-CD47 antibodies similarly enhanced the antitumor efficacy of RT/ICB by improving tumor control and survival (P<0.001). Using scRNA-seq and unbiased clustering, we found that anti-CD47 eliminated an entire cluster of chronically inflamed TAMs, characterized by pro-inflammatory markers (IL1A, NOS2) and chemokines (CCL3, CXCL1/2/3). Anti-CD47 also reduced intratumoral neutrophils by eliminating a cluster of pathologically activated neutrophils, termed myeloid-derived suppressor cells (PMN-MDSCs) that expressed several markers of ferroptosis (TFRC, PTGS2, SLC3A2). Consistent with the potent immunosuppressive capacity of PMN-MDSCs, we found that anti-CD47 increased tumor-infiltrating lymphocytes including central memory TCF7+ T cells and CD19+ B cells. Lastly, by inference and analysis of cell-cell communication (CellChat), we found that anti-CD47 strengthened the interactions between TAMs and CD8+ T cells compared to RT/ICB alone.

CONCLUSION

Our data collectively indicate that resistance to RT/ICB in the EO771 model Is driven by innate immune cells including neutrophils and chronically inflamed TAMs. Targeted disruption of the CD47-SIRPα axis is a promising approach to overcoming immune resistance by reprogramming TAMs and eliminating PMN-MDSCs.

Quality of Life Results of Addition of Androgen Deprivation Therapy and Pelvic Lymph Node Treatment to Prostate Bed Salvage Radiotherapy: NRG Oncology/RTOG 0534 SPPORT

PURPOSE/OBJECTIVE(S)

Report the quality of life (QOL) analysis of the SPPORT trial of men with a detectable prostate specific antigen (PSA) after prostatectomy for prostate cancer randomized to (Arm 1) salvage prostate bed radiotherapy (PBRT), (Arm 2) 4-6 months of short-term androgen deprivation therapy (STADT) + PBRT, and (Arm 3) pelvic lymph node radiotherapy (PLNRT) + STADT + PBRT. Primary analysis established a benefit of adding PLNRT and STADT to PBRT. There was higher short term but no statistically significant difference in long term adverse events with the exception of blood or bone marrow events.

MATERIALS/METHODS

QOL endpoints were assessed at baseline, 6 weeks after RT start, 1 and 5 years, including Expanded Prostate Cancer Index Composite (EPIC) (bowel, urinary, sexual, and hormonal domains), Hopkins Symptom Checklist (HSCL-25) (depressive symptoms), and the EuroQol (EQ-5D) (health state weights used in quality adjusted life years (QALYs). In addition to statistical significance, differences in scores were assessed using 0.5 standard deviation (SD) as the criterion for clinical importance. Difference among arms was assessed using pairwise t-tests, Fisher's exact test, and mixed effects regression modeling. To control for multiplicity, the p-value required for statistical significance is p<0.025.

RESULTS

Six hundred forty-four patients consented to QOL, about 210 on each arm. Baseline characteristics were not significantly different among arms: 81% were white and 54% <65 years. For EPIC, bowel domain scores decreased at 6 weeks post-RT then increased by years 1 and 5, although not to baseline levels. One clinically significant difference in bowel scores was Arm 3 vs. Arm 1 at 6 weeks. For the urinary domain, scores decreased at 6 weeks post-RT and remained below baseline at 1 and 5 years, but there were no significant differences among arms. For the sexual domain, there were statistically significant differences between arms at 6 weeks and 1 year with patients receiving STADT exhibiting poorer sexual QOL scores. By year 5 the differences were no longer significant. A similar pattern was seen for the hormonal domain. For HSCL-25, differences at 6 weeks were statistically but not clinically significant, and there were no significant differences at the later time points. Comparisons of QALYs for overall survival over an 8-year horizon showed no significant group differences, with a mean of about 7.8 in each arm. Regarding freedom from progression, QALY means were 5.7, 6.5, and 7.4 years for Arms 1, 2, and 3, respectively, with a significant difference between Arms 3 and 1 (p = <.001) favoring the more intensive treatment.

CONCLUSION

While QOL generally declined among all arms at 6 weeks post RT, there were no clinically significant differences in QOL among arms at 5 years. QALYs for freedom from progression favored STADT + PLNRT + PBRT for salvage treatment of prostate cancer.

The evolution of chemotherapy for the treatment of prostate cancer

Chemotherapy has been explored as a treatment option for metastatic prostate cancer since the early 1980s. Docetaxel, a taxane chemotherapeutic, was approved for the treatment of men with metastatic castration-resistant prostate cancer in 2004, and is now standard of care for late stage disease. Recent clinical studies demonstrated that patients with metastatic castration-sensitive disease, and possibly those with high-risk localized prostate cancer also benefit from docetaxel administration, expanding the role of chemotherapy in the prostate cancer treatment landscape. Another taxane, cabazitaxel, is approved for post-docetaxel metastatic castration-resistant prostate cancer. Taxanes and other chemotherapeutics, such as carboplatin, are now being tested in combination regimens. This review presents an outline of recent and ongoing clinical studies assessing docetaxel and its derivative cabazitaxel at different stages of the disease, and in various combinations with other agents. We summarize current knowledge on biomarkers predictive of response to chemotherapy, which may in future be used to guide individualized treatment decisions.

Initial report of RTOG 9601, a phase III trial in prostate cancer: Effect of anti-androgen therapy (AAT) with bicalutamide during and after radiation therapy (RT) on freedom from progression and incidence of metastatic disease in patients following radical prostatectomy (RP) with pT2-3,N0 disease and elevated PSA levels

1

Background: To test if long term AAT when combined with RT in these patients (pts) with prostate cancer (PC) will improve cancer control outcomes as well as overall survival (OS).

Methods: Post-RP pts with pT3,N0 or with pT2,N0 (and positive margins) who have an elevated PSA were entered on a phase III, double-blinded, placebo-controlled trial of RT alone (64.8 Gy in 1.8 Gy fractions) vs RT + AAT (24 months of bicalutamide, 150mg daily) during and after RT. The primary end point is OS.

Results: From 3/98 to 3/03, 771 eligible pts (median age 65) were randomized to RT + AAT (387) or RT alone (383). Pretreatment characteristics were balanced. 672 (87%) had a PSA nadir after RP of < 0.5 ng/mL. 655 (85%) had an entry PSA value of <1.6, 115 (15%) had an entry PSA of 1.6-3.9. Median follow-up was 7.1 years. Actuarial OS at 7 years was 91% for RT + AAT and 86% for RT alone. Too few primary end-point events have occurred to allow a statistical comparison between groups. Freedom from PSA progression (FFP) at 7 years was 57% for RT + AAT and 40% for RT alone (P < 0.0001); for 226 pts with GS < 7 were 63% and 50% (P<0.02), for 411 GS 7 these were 55% and 39% (P<0.0006), and for 134 GS 8-10 were 56% and 26% (P < 0.0008). The 7-yr cumulative incidence of metastatic PC was less in the RT and AAT arm, 7% vs 13% in the RT arm (p<0.041). Late grade 3-4 toxicities were similar in both arms. By category the combined grade 3-4 toxicities for RT + AAT and RT alone were: bladder 6% vs 5% bowel 2% vs 1%, cardiac 3% vs 2%. Gynecomastia (mostly grades 1-2) differed significantly, 89% vs15%. In the RT + AAT arm grade 3 was the highest liver toxicity, which occurred in 3 pts.

Conclusions: The addition of 24 months of bicalutamide 150 mg daily during and after RT significantly improved FFP and reduced the incidence of metastatic PC without adding significantly to RT toxicity. The significance of benefit in OS, as well analysis of risk-stratified subsets, wait longer follow-up.

No significant financial relationships to disclose.

Using Gleason pattern 5 to refine risk stratification for prostate cancer patients treated with dose-escalated radiotherapy and androgen-deprivation therapy

15

Background: The division of Gleason score (GS) into three categories (2-6, 7, 8-10), may not fully utilize its prognostic power as shown by recent reports demonstrating that the presence of Gleason Pattern 5 (GP5) is a strong adverse prognostic factor. Therefore, we analyzed clinical outcomes for patients treated with dose-escalated radiation therapy (RT) based upon the presence or absence of GP5 within the biopsy specimens.

Methods: Clinical outcomes were analyzed for 718 men treated for localized prostate cancer with definitive external beam RT to at least 75 Gy. We assessed the impact of GP5 as well as pre-treatment and treatment related factors on freedom from biochemical failure (FFBF), freedom from metastasis (FFM), cause-specific survival (CSS), and overall survival (OS).

Results: Median follow-up was 64 months. At biopsy, 89% of patients had no GP5 while 11% had GP5. There was no difference in age, co-morbid illness, clinical T-stage, PSA, or the use or duration of androgen deprivation therapy (ADT) between GS8 without GP5 and GS8-10 with GP5. The presence of GP5 predicted lower FFM (p<0.002 [HR: 3.4{1.7-7.1}]), CSS (p<0.0001 [HR: 12.9 {5.4-31}]), and OS (p<0.0001 [HR: 3.6 {2.0-6.5}]) when compared to GS8 (without GP5). Ten-year FFM, CSS, and OS were 89%, 98%, and 57% for those with Gleason 8 prostate cancer without GP5 as compared to 61%, 55%, and 31% for those with GP5. In addition, both FFM and CSS were strongly influenced by ADT use concurrent with RT. On multivariate analysis GP5 was the strongest prognostic factor for all clinical end-points.

Conclusions: The presence of GP5 predicts for worse clinical behavior, which therefore needs to be accounted for by risk stratification schemes. Further intensification of local and/or systemic therapy may be appropriate for such patients.

No significant financial relationships to disclose.

Use of percent positive biopsy cores to predict prostate cancer–specific death in patients treated with dose-escalated radiotherapy

35

Background: The percent of positive biopsy cores (PPC)-considered a surrogate of local disease burden-has been shown to predict biochemical failure (BF) after external beam radiation therapy (EBRT), but most series have used conventional dose RT. Dose-escalated RT has been demonstrated to improve prostate cancer outcomes, but the value of PPC is unclear in the setting of RT doses high enough to decrease local failure.

Methods: A retrospective evaluation was performed of 651 patients treated to ≥75 Gy with biopsy core information available. Patients were stratified for PPC by quartile, and differences by quartile in BF, freedom from metastasis (FFM), cause specific survival (CSS), and overall survival (OS) were assessed using the log-rank test. Receiver operated characteristic (ROC) curve analysis was utilized to determine an optimal cut-point for PPC. Cox proportional hazards multivariate regression was utilized to assess the impact of PPC on clinical outcome when adjusting for risk group.

Results: With median follow-up of 62 months the median number of cores sampled was 7 (IQR: 6–12) with median PPC in 38% (IQR: 17%-67%). On log-rank test, BF, FFM, and CSS were all associated with PPC (p < 0.005 for all), with worse outcomes only for the highest PPC quartile (>67%). There was no observed difference in OS based upon PPC. ROC curve analysis confirmed a cut-point of 67% as most closely associated with CSS (p<0.001, AUC=0.71). On multivariate analysis after adjusting for NCCN risk group and ADT use, PPC>67% increased the risk for BF (p<0.0001, HR:2.1 [1.4–3.0]), FFM (p<0.05, HR:1.7 [1.1 to 2.9]), and CSS (p<0.06 (HR:2.1 [1.0–4.6]). When analyzed as a continuous variable controlling for risk group and ADT use, increasing PPC increased the risk for BF (p < 0.002), metastasis (p < 0.05), and CSS (p < 0.02), with a 1–2% increase in relative risk of recurrence for each 1% increase in the PPC.

Conclusions: For patients treated with dose-escalated RT, the PPC adds prognostic value but at a higher cut-point then previously utilized. Patients with PPC >67% remain at increased risk for failure even with dose-escalated EBRT and may receive benefit from further intensification of therapy.

No significant financial relationships to disclose.

Randomized trial of short-course versus long-course radiotherapy for palliation of painful vertebral bone metastases: A retrospective analysis of RTOG 97–14

9521

Background: RTOG 97–14 [Hartsell et al, breast/prostate cancer patients (pts) with painful bone metastases randomized to 8 Gy/1 fraction or 30 Gy/10 fractions], revealed no difference in pain relief or narcotic use 3 months post randomization. The 8 Gy regimen resulted in fewer acute toxicities, but higher rates of retreatment for recurrent pain. Single 8 Gy fractions for painful vertebral bone mets have not been well accepted, possibly due to provider concerns about efficacy and toxicity. The present study evaluates treatment differences in the subset of pts treated specifically for painful vertebral bone mets (PVBM). Methods: PVBM were treated to the cervical, thoracic, and/or lumbar spine. Chi-square test was used to evaluate population differences between PVBM and non-PVBM. Amongst PVBM, differences in retreatment rates (cumulative incidence method, Gray's test) and in pain relief/BPI worst pain score, narcotic use, and toxicity 3 months post randomization (chi-square test) were evaluated. Results: Of 909 eligible pts, 235 (26%) were PVBM. PVBM and non-PVBM pts differed in % of males [55% vs. 47%,p=0.03] and pts with multiple painful sites [57% vs. 38%,p<0.01]. Amongst PVBM, more 30 Gy pts had multiple sites treated [65% vs. 49%, p=0.02]. T [10% vs. 20%, p=0.01] here was no statistically significant difference (8 vs. 30 Gy) in pain relief [70% vs. 62%, p=0.59] or narcotic use [27% vs. 24%, p=0.76] at 3 months. There were significant differences in acute grade 2–4 toxicityand acute grade 2–4 GI toxicity [6% vs. 14%, p=0.01] at 3 months, lower toxicity seen in 8 Gy. Late toxicity was rare, with 1 grade 3 CNS event (8 Gy) and 1 grade 4 lung event (30 Gy). 8 Gy showed significantly higher 3-year retreatment rates [15% vs. 5%, p=0.01]. Conclusions: Although a clinically different pt population, the results for PVBM are comparable to those of the entire study population. Both 8 Gy/1 fraction and 30 Gy/10 fractions resulted in comparable pain relief and narcotic use at 3 months. Both were well tolerated with few adverse effects. 8 Gy had less acute toxicity, and a higher need for retreatment than 30 Gy. This may have implications for future research comparing single fraction conventional radiation therapy with stereotactic spine radiosurgery.

No significant financial relationships to disclose.

Patterns of practice in radiation therapy for non-small cell lung cancer among members of American Society of Therapeutic Radiology and Oncology

7693

Purpose: To investigate the dominant pattern of current practice in radiation therapy (RT) for lung cancer among members of American Society of Therapeutic Radiology and Oncology (ASTRO). Methods: A 35-item survey was designed by a panel of 8 board certified radiation oncologists regarding RT for lung cancer. Surveys were sent through email to 3,800 radiation oncologist members on September 10, 2006, with the results collected online on December 10, 2006. Here we report results on radiation decisions for non-small cell lung cancer (NSCLC). Results: The response rate was 19% (n = 727). The respondents saw an average of 8 consults (ranged 1–25) monthly during the survey time (summing up to a total of >60,000 new cases yearly). For stage I peripherally located NSCLC, 33%, 10% and 20% of respondents reported conventional fractionated, hypofractioned and stereotactic RT, respectively. Another 25% of respondents would have offered stereotactic RT if this technique were available at their center. For stage I centrally located tumors, 78% of respondents did not agree with, but 10% selected, stereotactic RT. For stage II and III, 76% of respondents selected 60–70 Gy in 1.8–2 Gy with chemotherapy. With regard to the combined modality approach for stage II and III disease, 76–77% of respondents selected concurrent chemoRT followed by adjuvant chemotherapy, and 11–16% sequential followed by concurrent chemoRT for patients with good performance status. For stage IV NSCLC with remarkable local disease, the consideration of RT ranged from 0 Gy, 3 Gyx10, 3 Gyx15, 2.5 Gyx20, to 2 Gyx30 in 27%, 17%, 8%, 13%, and 21% of respondents, respectively. Conclusions: The dominant pattern of practice for stage II/III disease is concurrent chemoRT, consistent with results of phase III trials. The treatment decisions for stage I and IV disease are diverse, partially due to technology advancement and the lack of large phase III trials.

No significant financial relationships to disclose.

Body mass index and mortality in men treated for locally advanced prostate cancer: An analysis of RTOG 85–31

5128

Background: Greater body mass index (BMI) is associated with shorter time to prostate-specific antigen (PSA) failure following radical prostatectomy. We investigated whether BMI is associated with prostate cancer-specific mortality (PCSM) in a large randomized trial of men treated with radiation therapy (RT) and androgen deprivation therapy (ADT) for locally advanced prostate cancer. Methods: Between 1987 and 1992, 945 eligible men with locally advanced prostate cancer were enrolled on a phase III trial (RTOG 85- 31) and randomized to RT and immediate goserelin (Arm I) or RT alone followed by goserelin at relapse (Arm II). Height and weight data were available at baseline for 788 (83%) subjects. Cox regression analyses were performed to evaluate the relationships between BMI and all-cause mortality, PCSM, and non-prostate cancer mortality. Covariates included age, race, treatment arm, history of prostatectomy, nodal involvement, Gleason score, clinical stage, and BMI. Results: The 5-year PCSM rate for men with BMI<25kg/m2 was 6.5%, compared to 13.1% and 12.2% in men with BMI=25-<30 and BMI=30, respectively (Gray’s p=0.005). In multivariable analyses, as shown in the Table , greater BMI was significantly associated with higher PCSM [for BMI=25-<30, hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.02–2.27, p=0.04; for BMI=30, HR 1.65, 95% CI 1.02–2.66, p=0.04]. BMI was not associated with non-prostate cancer or all-cause mortality. Conclusions: Greater baseline BMI is independently associated with higher PCSM in men with locally advanced prostate cancer. Further studies are warranted to evaluate the mechanism(s) for increased mortality and to assess whether weight loss after prostate cancer diagnosis alters disease course.

[Table: see text]

No significant financial relationships to disclose.

Defining High Risk Prostate Cancer With Risk Groups and Nomograms: Implications for Designing Clinical Trials

PURPOSE

Death from prostate cancer is usually preceded by metastases and it usually occurs in men with high risk disease who experienced biochemical failure with a short prostate specific antigen doubling time. We developed a model for determining disease specific survival in prostate cancer.

MATERIALS AND METHODS

We used the model for defining high risk prostate cancer that was developed by the Radiation Therapy Oncology Group and combined it with the Kattan nomogram for predicting the risk of metastases. We selected 414 Radiation Therapy Oncology Group intermediate and high risk patients who were treated with external beam radiotherapy alone. Excluded were patients with low risk disease. The Kaplan-Meier product limit method was used to estimate the probability of freedom from biochemical failure, overall survival and disease specific survival.

RESULTS

A significant difference was observed in freedom from biochemical failure, disease specific survival and overall survival among the 3 tertiles created by the nomogram using the cutoff points less than 8.5%, 8.5% to 15% and greater than 15% (p <0.001, 0.0002 and 0.0003, respectively). Only the risk of metastases using the categorized nomogram score (less than 8.5% and 8.5% to 15% vs greater than 15%), not preradiotherapy prostate specific antigen or Radiation Therapy Oncology Group risk (Radiation Therapy Oncology Group 2 vs 3), was a significant predictor of disease specific and overall survival for intermediate/high risk patients and intermediate/high risk with 15% or less risk for metastases.

CONCLUSIONS

We combined a risk group stratification scheme for disease specific survival with a nomogram predicting the risk of metastases and created a model that may be useful for designing phase III trials with metastases and disease specific survival as study end points.

Does timing of androgen deprivation influence radiation-induced toxicity? A secondary analysis of Radiation Therapy Oncology Group protocol 9413

4655

Background: We conducted a secondary analysis of RTOG 9413 to compare if the timing of antiandrogen-therapy, concomitant versus adjuvant, influences the incidence of rectal toxicity in whole pelvic radiotherapy. Methods: For the purpose of this secondary analysis, we analyzed the 2 of the 4 arms of the study, in which all patients received radiotherapy to the whole pelvis followed by a boost to the prostate and excluded the two arms that received prostate only radiotherapy. The 2 arms differed only in the timing of the total of 4 months of total androgen deprivation (TAD): arm I (320 patients), TAD was begun 2 months before the start of radiotherapy and continued during radiotherapy. Arm III (319 patients), TAD started immediately after the completion of radiotherapy. Both acute rectal and acute urinary toxicities (CTC v.2.0), testosterone (measured at baseline and yearly after) and other patients data were modeled using the multivariate logistic regression and the multivariate Cox-proportional hazards regression. Results: Median follow up for all patients is 6.0 and 5.8 years (arm I and II, resp.). 43 (13%) patients in each arm had abnormally low testosterone before start of TAD. Late grade 2 - 5 rectal toxicity occurred in 16% and 13% and urinary toxicity in 18% and 20% (arm I and II, resp.). Frequency (or occurrence) of late rectal toxicity (grade 0–1 vs. 2–5, p = 0.2170) and late urinary toxicity (grade 0–1 vs. 2–5, p = 0.4204) are not significantly different between the two arms. The only risk factors for late rectal toxicity in a multivariate regression model was acute rectal toxicity (OR 1.48, p = 0.025), but not abnormal testosterone level at baseline (p = 0.718) or treatment arm (p = 0.874). For late urinary toxicity: age (OR = 1.588, p = 0.010), RT field size (OR 1.004, p < 0.025), baseline testosterone (OR 1.718, p = 0.028), and acute (grade 2–4) toxicity (OR = 1.664, p = 0.006) but not treatment arm (p = 0.928) were risk factors. Conclusions: While late toxicity was not different for concomitant vs. adjuvant hormonal therapy, an abnormally low testosterone level at baseline is a risk factor for late urinary toxicity and not late rectal toxicity.

No significant financial relationships to disclose.

Comparison of external radiation therapy vs radical prostatectomy in lymph node positive prostate cancer patients

INTRODUCTION

Treatment options for lymph node positive prostate cancer are limited. We retrospectively compared patients who underwent external radiotherapy (ERT) to patients treated by radical prostatectomy (RPX).

MATERIALS AND METHODS

A total of 102 lymph node positive patients from the RPX series at Ulm University were evaluated. In all, 76 patients received adjuvant androgen withdrawal as part of their primary treatment. In the ERT group, 44 patients were treated at the University of Michigan using a fractionated regimen. Of these, 21 patients received early adjuvant hormonal therapy. Patients with neoadjuvant therapy before RPX or ERT were excluded.

RESULTS

In the RPX group, PSA nadir (nadir < or = 0.2 vs > 0.2 ng/ml) showed a strong association with outcome. In the ERT group, pretreatment PSA was an independent predictor of outcome (P = 0.04) and patients with adjuvant hormonal therapy had a significant longer recurrence-free interval compared to patients without adjuvant therapy (P = 0.004). Comparing only patients with adjuvant hormonal treatment after cancer-specific therapy, the ERT-treated patients had a borderline longer PSA recurrence-free survival time compared to the RPX-treated patients (P = 0.05).

CONCLUSIONS

In case of positive lymph nodes, RPX and ERT might be considered and need to be explained to the patient. For future treatment decisions, the presented findings and a potential survival benefit need to be evaluated in a larger prospective setting.

Ki-67 staining is a strong predictor of distant metastasis and mortality for men with prostate cancer treated with radiotherapy plus androgen deprivation: Radiation Therapy Oncology Group Trial 92-02

PURPOSE

The Ki-67 staining index (Ki67-SI) has been associated with prostate cancer patient outcome; however, few studies have involved radiotherapy (RT) -treated patients. The association of Ki67-SI to local failure (LF), biochemical failure (BF), distant metastasis (DM), cause-specific death (CSD) and overall death (OD) was determined in men randomly assigned to short term androgen deprivation (STAD) + RT or long-term androgen deprivation (LTAD) + RT.

PATIENTS AND METHODS

There were 537 patients (35.5%) on Radiation Therapy Oncology Group (RTOG) 92-02 who had sufficient tissue for Ki67-SI analysis. Median follow-up was 96.3 months. Ki67-SI cut points of 3.5% and 7.1% were previously found to be related to patient outcome and were examined here in a Cox proportional hazards multivariate analysis (MVA). Ki67-SI was also tested as a continuous variable. Covariates were dichotomized in accordance with stratification and randomization criteria.

RESULTS

Median Ki67-SI was 6.5% (range, 0% to 58.2%). There was no difference in the distribution of patients in the Ki-67 analysis cohort (n = 537) and the other patients in RTOG 92-02 (n = 977) by any of the covariates or end points tested. In MVAs, Ki67-SI (continuous) was associated with LF (P =.08), BF (P =.0445), DM (P <.0001), CSD (P <.0001), and OD (P =.0094). When categoric variables were used in MVAs, the 3.5% Ki67-SI cut point was not significant. The 7.1% cut point was related to BF (P =.09), DM (P =.0008), and CSD (P =.017). Ki67-SI was the most significant correlate of DM and CSD. A detailed analysis of the hazard rates for DM in all possible covariate combinations revealed subgroups of patients treated with STAD + RT that did not require LTAD.

CONCLUSION

Ki67-SI was the most significant determinant of DM and CSD and was also associated with OD. The Ki67-SI should be considered for the stratification of patients in future trials.

What does postradiotherapy PSA nadir tell us about freedom from PSA failure and progression-free survival in patients with low and intermediate-risk localized prostate cancer?

OBJECTIVES

To determine whether the post-external beam radiotherapy (RT) prostate-specific antigen nadir (nPSA) improves our ability to predict freedom from PSA failure, progression-free survival (PFS), and overall survival. Controversy regarding the importance of nPSA after external beam RT as a prognostic indicator for patients with localized prostate cancer has continued.

METHODS

This analysis was based on the data from 748 patients with low and intermediate-risk localized prostate cancer treated with external beam RT alone. Patients were categorized by nPSA quartile groups with cutpoints of less than 0.3, 0.3 to less than 0.6, 0.6 to less than 1.2, and 1.2 ng/mL or greater. Both univariate and multivariate analyses were used to determine the significance of nPSA on PSA failure (American Society for Therapeutic Radiology Oncology consensus definition), PFS (death after PSA failure), and overall survival (death from any cause).

RESULTS

Freedom from PSA failure was strongly associated with nadir quartile groups (P <0.0001). PFS was also significantly different statistically among nadir quartile groups (P = 0.02). No statistically significant difference was found in overall survival associated with nPSA at this point.

CONCLUSIONS

nPSA is a strong independent predictor of freedom from PSA failure and PFS in patients with low and intermediate-risk localized prostate cancer treated with RT alone. Longer follow-up and larger patient numbers are required to confirm these observations.

Influence of 3D-CRT pelvic irradiation on outcome in prostate cancer treated with external beam radiotherapy

PURPOSE

The role of pelvic irradiation (PRT) in the treatment of prostate cancer remains unclear. We reviewed our institution's experience with three-dimensional conformal external beam radiotherapy (3D-CRT) during the prostate-specific antigen era to determine the influence of PRT on the risk of biochemical recurrence in patients who have a predicted risk of lymph node involvement.

METHODS AND MATERIALS

Between March 1985 and January 2001, 1832 patients with clinically localized prostate cancer were treated with definitive 3D-CRT. All treatments involved CT planning to ensure coverage of the intended targets. Treatment consisted of prostate-only treatment, prostate and seminal vesicle treatment, or PRT of lymph nodes at risk followed by a boost. To create relatively homogenous analysis groups, each patient's percentage of risk of lymph node (%rLN) involvement was assigned by matching the patient's T stage, Gleason score, and initial prostate-specific antigen level to the appropriate value as described in the updated Partin tables. Three categories of %rLN involvement were defined: low, 0-5%; intermediate, >5-15%; and high, >15%. Biochemical recurrence was defined as the first occurrence of either the American Society for Therapeutic Radiology and Oncology consensus definition of prostate-specific antigen failure or the initiation of salvage hormonal therapy for any reason.

RESULTS

The risk status (%rLN) could be determined for 709 low-risk, 263 intermediate-risk, and 309 high-risk patients. The actuarial freedom from biochemical recurrence (bNED) and the log-rank test for the similarity of the control and treatment survival functions are reported for each risk group. Multivariate analysis demonstrated a statistically significant benefit for the entire population treated with PRT, with a relative risk reduction of 0.72 (95% confidence interval 0.54-0.97). Although the multivariate analysis could not determine the patient population that would most benefit from PRT, the beneficial effect appeared to be most pronounced within the intermediate-risk group. Univariate analysis revealed that the intermediate-risk patients treated with PRT had an improved 2-year bNED rate, 90.1% vs. 80.6% (p = 0.02), and both low-risk and high-risk patients treated with PRT had statistically similar 2-year bNED rates compared with those who did not receive it.

CONCLUSION

Pelvic 3D-CRT appears to improve bNED in prostate cancer patients. Additional studies are needed to elucidate the %rLN population for which this treatment should be recommended.

Definitions of biochemical failure in prostate cancer following radiation therapy

PURPOSE

The American Society for Therapeutic Radiology and Oncology (ASTRO) published a consensus panel definition of biochemical failure following radiation therapy for prostate cancer. In this paper, we develop a series of alternative definitions of biochemical failure. Using data from 688 patients, we evaluated the sensitivity and specificity of the various definitions, with respect to a defined "clinically meaningful" outcome.

METHODS AND MATERIALS

The ASTRO definition of biochemical failure requires 3 consecutive rises in prostate-specific antigen (PSA). We considered several modifications to the standard definition: to require PSA rises of a certain magnitude, to consider 2 instead of 3 rises, to require the final PSA value to be greater than a fixed cutoff level, and to define biochemical failure based on the slope of PSA over 1, 1.5, or 2 years. A clinically meaningful failure is defined as local recurrence, distant metastases, initiation of unplanned hormonal therapy, unplanned radical prostatectomy, or a PSA > 25 later than 6 months after radiation.

RESULTS

Requiring the final PSA in a series of consecutive rises to be larger than 1.5 ng/mL increased the specificity of biochemical failure. For a fixed specificity, defining biochemical failure based on 2 consecutive rises, or the slope over the last year, could increase the sensitivity by up to approximately 20%, compared to the ASTRO definition. Using a rule based on the slope over the previous year or 2 rises leads to a slightly earlier detection of biochemical failure than does the ASTRO definition. Even with the best rule, only approximately 20% of true failures are biochemically detected more than 1 year before the clinically meaningful event time.

CONCLUSION

There is potential for improvement in the ASTRO consensus definition of biochemical failure. Further research is needed, in studies with long follow-up times, to evaluate the relationship between various definitions of biochemical failure and true clinical outcome.

A meta-analysis of meausures of self-esteem for young children: a framework for future measures

The objective of this study was to synthesize information from literature on measures of the self in young children to create an empirical framework for developing future methods for measuring this construct. For this meta-analysis, all available preschool and early elementary school self-esteem studies were reviewed. Reliability was used as the criterion variable and the predictor variables represented different aspects of methodology that are used in testing an instrument: study characteristics, method characteristics, subject characteristics, measure characteristics, and measure design characteristics. Using information from two analyses, the results indicate that the reliability of self-esteem measures for young children can be predicted by the setting of the study, number of items in the scale, the age of the children being studied, the method of data collection (questionnaires or pictures), and the socioeconomic status of the children. Age and number of items were found to be critical features in the development of reliable measures for young children. Future studies need to focus on the issues of age and developmental limitations on the complicated problem of how young children actually think about the self and what methods and techniques can aid in gathering this information more accurately.

Pediatric anogenital exam: a theory-driven exploration of anticipatory appraisals and affects

Smith and Lazarus's 1990 and 1993 theory of cognition-emotion associations guided this exploration of individuals' pre-exam experiences. The study also tested the model's integrity during a stressful event and examined its downward extension to children. A total of 47 girls ages 8 to 14 (M = 11.57, SD = 2.14) and 109 adult guardians of female patients (all ages) completed a brief questionnaire about their pre-exam thoughts and feelings. The majority of participants viewed the impending exam as important and desirable, reported optimism and confidence in their ability to cope or adjust, and described mild-moderate anxiety as well as moderate-high hope/gladness. The majority of adults also reported relatively high levels of sadness. Data supported the model's cognition-emotion associations. This theory-driven research offers a richer understanding of children who may have been sexually abused and their supportive adult guardians and encourages more positive and realistic expectations for these individuals.

Development and validation of the expanded prostate cancer index composite (EPIC) for comprehensive assessment of health-related quality of life in men with prostate cancer

OBJECTIVES

Health-related quality of life (HRQOL) is an increasingly important endpoint in prostate cancer care. However, pivotal issues that are not fully assessed in existing HRQOL instruments include irritative urinary symptoms, hormonal symptoms, and multi-item scores quantifying bother between urinary, sexual, bowel, and hormonal domains. We sought to develop a novel instrument to facilitate more comprehensive assessment of prostate cancer-related HRQOL.

METHODS

Instrument development was based on advice from an expert panel and prostate cancer patients, which led to expanding the 20-item University of California-Los Angeles Prostate Cancer Index (UCLA-PCI) to the 50-item Expanded Prostate Index Composite (EPIC). Summary and subscale scores were derived by content and factor analyses. Reliability and validity were assessed by test-retest correlation, Cronbach's alpha coefficient, interscale correlation, and EPIC correlation with other validated instruments.

RESULTS

Test-retest reliability and internal consistency were high for EPIC urinary, bowel, sexual, and hormonal domain summary scores (each r >/=0.80 and Cronbach's alpha >/=0.82) and for most domain-specific subscales. Correlations between function and bother subscales within domains were high (r >0.60). Correlations between different primary domains were consistently lower, indicating that these domains assess distinct HRQOL components. EPIC domains had weak to modest correlations with the Medical Outcomes Study 12-item Short-Form Health Survey (SF-12), indicating rationale for their concurrent use. Moderate agreement was observed between EPIC domains relevant to the Functional Assessment of Cancer Therapy Prostate module (FACT-P) and the American Urological Association Symptom Index (AUA-SI), providing criterion validity without excessive overlap.

CONCLUSIONS

EPIC is a robust prostate cancer HRQOL instrument that complements prior instruments by measuring a broad spectrum of urinary, bowel, sexual, and hormonal symptoms, thereby providing a unique tool for comprehensive assessment of HRQOL issues important in contemporary prostate cancer management.

Overall survival after prostate-specific-antigen-detected recurrence following conformal radiation therapy

PURPOSE

To study the significance, in terms of overall and cause-specific survival, of biochemical failure after conformal external-beam radiation therapy (RT) for prostate cancer.

METHODS AND MATERIALS

Of the 1844 patients in the Radiation Oncology prostate cancer database, 718 were deemed eligible. Patients excluded were those with N1 or M1 disease, those treated after radical prostatectomy, those who received hormone therapy before radiation therapy, and those who died, failed clinically, or had no PSA response in the first 6 months after RT. Patients included were required to have a minimum of 2 post-RT PSAs separated by at least 1 week. Biochemical relapse was defined as 3 consecutive PSA rises. This resulted in 154 patients with biochemical failure. Survival was calculated from the third PSA elevation. The rate of rise of PSA was calculated by fitting a regression line to the four rising PSAs on a ln PSA vs. time plot.

RESULTS

There were 41 deaths among the 154 patients with failure in 23 of the 41 due to prostate cancer. The overall survival after failure was 58% at 5 years, while the cause-specific failure was 73% at 5 years. Among the 154 failures, several factors were evaluated for an association with overall survival: age at failure, pre-RT PSA, PSA at second rise, PSA nadir, time from RT to failure, time to nadir, Gleason score, T-stage, and rate of rise, both from the nadir and from the beginning of the rise. None of these factors were significantly associated with an increased risk of death. As expected, the group of patients with biochemical failure have significantly worse prognostic factors than those without biochemical failure: median pre-RT PSA 15.9 vs. 9.0 (p < 0.001), and Gleason score of 7 or greater for 48% of subjects vs. 40% (p = 0.1). Relative PSA rise and slope of ln PSA vs. time were associated with cause-specific mortality (p < 0.001 and p = 0.007, respectively).

CONCLUSION

Overall survival after conformal radiotherapy for prostate cancer remains high 5 years after biochemical failure. This high survival rate occurs even though the group of patients with biochemical failure has worse than average adverse preradiation prognostic factors. Thus, although biochemical failure can identify patients who have recurrent disease after RT, the ultimate relationship between this endpoint and death remains to be better defined.

A comparison of ventilatory prostate movement in four treatment positions

PURPOSE

To ensure target coverage during radiotherapy, all sources of geometric uncertainty in target position must be considered. Movement of the prostate due to breathing has not traditionally been considered in prostate radiotherapy. The purpose of this study is to report the influence of patient orientation and immobilization on prostate movement due to breathing.

METHODS AND MATERIALS

Four patients had radiopaque markers implanted in the prostate. Fluoroscopy was performed in four different positions: prone in alpha cradle, prone with an aquaplast mold, supine on a flat table, and supine with a false table under the buttocks. Fluoroscopic movies were videotaped and digitized. Frames were analyzed using 2D-alignment software to determine the extent of movement of the prostate markers and the skeleton for each position during normal and deep breathing.

RESULTS

During normal breathing, maximal movement of the prostate markers was seen in the prone position (cranial-caudal [CC] range: 0.9-5.1 mm; anterior-posterior [AP] range: up to 3.5 mm). In the supine position, prostate movement during normal breathing was less than 1 mm in all directions. Deep breathing resulted in CC movements of 3.8-10.5 mm in the prone position (with and without an aquaplast mold). This range was reduced to 2.0-7.3 mm in the supine position and 0.5-2.1 mm with the use of the false table top. Deep breathing resulted in AP skeletal movements of 2.7-13.1 mm in the prone position, whereas AP skeletal movements in the supine position were negligible.

CONCLUSION

Ventilatory movement of the prostate is substantial in the prone position and is reduced in the supine position. The potential for breathing to influence prostate movement, and thus the dose delivered to the prostate and normal tissues, should be considered when positioning and planning patients for conformal irradiation.

Stereotactic radiosurgery of cerebral arteriovenous malformations with a multileaf collimator and a single isocenter

OBJECTIVE

To prospectively demonstrate the safety and efficacy of stereotactic radiosurgery for arteriovenous malformations (AVMs) of the brain with a linear accelerator fitted with a multileaf collimator.

METHODS

A novel radiosurgery system was developed at the University of Michigan Medical Center with a standard multileaf collimator and a computer-controlled radiotherapy system. Data were accumulated prospectively on all patients undergoing treatment with this system since treatment began in 1995.

RESULTS

Thirty-six patients with 37 AVMs have undergone treatment to date. At more than 3 years since treatment, 15 of 16 AVMs with a volume of less than 10 cc were proven to be obliterated by angiography or magnetic resonance imaging, and one was considered a treatment failure. At more than 24 months since therapy, all four AVMs with a volume of 10 to 25 cc were obliterated. Four patients with AVMs with a volume of more than 25 cc have undergone staged therapy, treating the entire volume to 10 Gy twice, but none has been followed long enough to demonstrate a final outcome. There were four transient and no permanent complications.

CONCLUSION

Our early data indicate that stereotactic radiosurgery of cerebral AVMs with a linear accelerator and a multileaf collimator is safe and effective. Large AVMs may be especially suitable for this mode of therapy. Staged treatment of very large AVMs seems to be a promising addition to standard treatment, but longer follow-up is necessary to confirm that complete obliteration can be achieved.

Prostate position late in the course of external beam therapy: patterns and predictors

PURPOSE

To examine prostate and seminal vesicles position late in the course of radiation therapy and to determine the effect and predictive value of the bladder and rectum on prostate and seminal vesicles positioning.

METHODS AND MATERIALS

Twenty-four patients with localized prostate cancer underwent a computerized tomography scan (CT1) before the start of radiation therapy. After 4-5 weeks of radiation therapy, a second CT scan (CT2) was obtained. All patients were scanned in the supine treatment position with instructions to maintain a full bladder. The prostate, seminal vesicles, bladder, and rectum were contoured. CT2 was aligned via fixed bony anatomy to CT1. The geometrical center and volume of each structure were obtained and directly compared.

RESULTS

The prostate shifted along a diagonal axis extending from an anterior-superior position to a posterior-inferior position. The dominant shift was to a more posterior-inferior position. On average, bladder and rectal volumes decreased to 51% (+/-29%) and 82% (+/-45%) of their pretreatment values, respectively. Multiple regression analysis (MRA) revealed that bladder movement and volume change and upper rectum movement were independently associated with prostate motion (p = 0.016, p = 0. 003, and p = 0.052 respectively).

CONCLUSION

Patients are often instructed to maintain a full bladder during a course of external beam radiation therapy, in the hopes of decreasing bladder and small bowel toxicity. However, our study shows that large bladder volumes late in therapy are strongly associated with posterior prostate displacement. This prostate displacement may result in marginal miss.

3D conformal radiation therapy (3DCRT) for high grade prostate cancer: a multi-institutional review

PURPOSE

To evaluate the results of 3DCRT and the effect of higher than traditional doses in patients with high grade prostate cancer, we compiled data from three institutions and analyzed the outcome of this relatively uncommon subset of prostate cancer patients.

METHODS AND MATERIALS

The 180 patients with Gleason score 8- 10 adenocarcinoma of the prostrate were treated with 3DCRT at the Univer sity of Michigan Health System, University of California-San Francisco, or Fox Chase Cancer. Eligible patients had T1-T4 NO or NX MO adenocarci noma with a pretreatment PSA. Pretreatment characteristics included: me dian age 72 years, 60.6% Gleason score 8 tumors, 57.6% T1-T2, and median pretreatment PSA 17.1 ng/ml (range 0.3-257.1). The total dose received was <70 Gy in 30%, 70-75 Gy in 37%, and >75 Gy in 33%, 27% received adju vant or neoadjuvant hormonal therapy. The median follow-up was 3.0 years for all patients and 16% of patients were followed up for at least 5 years.

RESULTS

The 5-year freedom from PSA failure was 62.5% for all patients and 79.3% in T1-T2 patients. Univariate analysis revealed that T-stage (T1-T2 vs. T3-T4), pretreatment PSA, and RT dose predicted for freedom from PSA failure. A 5-year overall survival for all patients was 67.3%. Only RT dose was predictive of 5-year overall survival on univariate analysis. Because a significant association was seen between T-stage and RT dose, the Cox proportional hazards model was performed separately for T1-T2 and T3-T4 tumors. None of the prognostic factors reached statistical significance for overall survival or freedom from PSA failure in T3-T4 patients or for overall survival in T1-T2 patients. Lower RT dose and higher pretreatment PSA predicted for PSA failure on multivariate analysis in T1-T2 patients.

CONCLUSION

This retrospective study from three institutions with experience in dose escalation suggests a dose effect for PSA control above 70 Gy in patients with T1-T2 high grade prostate cancer. These results are superior to surgery and emphasize the need for dose escalation in treating Gleason 8-10 prostate cancer.

Preliminary report of toxicity following 3D radiation therapy for prostate cancer on 3DOG/RTOG 9406

PURPOSE

A prospective Phase I dose escalation study was conducted to determine the maximally-tolerated radiation dose in men treated with three-dimensional conformal radiation therapy (3D CRT) for localized prostate cancer. This is a preliminary report of toxicity encountered on the 3DOG/RTOG 9406 study.

METHODS AND MATERIALS

Each participating institution was required to implement data exchange with the RTOG 3D quality assurance (QA) center at Washington University in St. Louis. 3D CRT capabilities were strictly defined within the study protocol. Patients were registered according to three stratification groups: Group 1 patients had clinically organ-confined disease (T1,2) with a calculated risk of seminal vesicle invasion of < 15%. Group 2 patients had clinical T1,2 disease with risk of SV invasion > or = 15%. Group 3 (G3) patients had clinical local extension of tumor beyond the prostate capsule (T3). All patients were treated with 3D techniques with minimum doses prescribed to the planning target volume (PTV). The PTV margins were 5-10 mm around the prostate for patients in Group 1 and 5-10 mm around the prostate and SV for Group 2. After 55.8 Gy, the PTV was reduced in Group 2 patients to 5-10 mm around the prostate only. Minimum prescription dose began at 68.4 Gy (level I) and was escalated to 73.8 Gy (level II) and subsequently to 79.2 Gy (level III). This report describes the acute and late toxicity encountered in Group 1 and 2 patients treated to the first two study dose levels. Data from RTOG 7506 and 7706 allowed calculation of the expected probability of observing a > or = grade 3 late effect more than 120 days after the start of treatment. RTOG toxicity scores were used.

RESULTS

Between August 23, 1994 and July 2, 1997, 304 Group 1 and 2 cases were registered; 288 cases were analyzable for toxicity. Acute toxicity was low, with 53-54% of Group 1 patients having either no or grade 1 toxicity at dose levels I and II, respectively. Sixty-two percent of Group 2 patients had either none or grade 1 toxicity at either dose level. Few patients (0-3%) experienced a grade 3 acute bowel or bladder toxicity, and there were no grade 4 or 5 toxicities. Late toxicity was very low in all patient groups. The majority (81-85%) had either no or mild grade 1 late toxicity at dose level I and II, respectively. A single late grade 3 bladder toxicity in a Group 2 patient treated to dose level II was recorded. There were no grade 4 or 5 late effects in any patient. Compared to historical RTOG controls (studies 7506, 7706) at dose level I, no grade 3 or greater late effects were observed in Group 1 and Group 2 patients when 9.1 and 4.8 events were expected (p = 0.003 and p = 0.028), respectively. At dose level II, there were no grade 3 or greater toxicities in Group 1 patients and a single grade 3 toxicity in a Group 2 patient when 12.1 and 13.0 were expected (p = 0.0005 and p = 0.0003), respectively. Multivariate analysis demonstrated that the relative risk of developing acute bladder toxicity was 2.13 if the percentage of the bladder receiving > or = 65 Gy was more than 30% (p = 0.013) and 2.01 if patients received neoadjuvant hormonal therapy (p = 0.018). The relative risk of developing late bladder complications also increased as the percentage of the bladder receiving > or = 65 Gy increased (p = 0.026). Unexpectedly, there was a lower risk of late bladder complications as the mean dose to the bladder and prescription dose level increased. This probably reflects improvement in conformal techniques as the study matured. There was a 2.1 relative risk of developing a late bowel complication if the total rectal volume on the planning CT scan exceeded 100 cc (p = 0.019).

CONCLUSION

Tolerance to high-dose 3D CRT has been better than expected in this dose escalation trial for Stage T1,2 prostate cancer compared to low-dose RTOG historical experience. With strict quality assurance standards and review, 3D CRT can be safely studied in a co

The effect of patient position and treatment technique in conformal treatment of prostate cancer

PURPOSE

The relative value of prone versus supine positioning and axial versus nonaxial beam arrangements in the treatment of prostate cancer remains controversial. Two critical issues in comparing techniques are: 1) dose to critical normal tissues, and 2) prostate stabilization.

METHODS AND MATERIALS

Ten patients underwent pretreatment CT scans in one supine and two prone positions (flat and angled). To evaluate normal tissue exposure, prostate/seminal vesicle volumes or prostate volumes were expanded 8 mm and covered by the 95% isodose surface by both 6-field axial and 4-field nonaxial techniques. A total of 280 dose-volume histograms (DVHs) were analyzed to evaluate dose to rectal wall and bladder relative to patient position and beam arrangement. A CT scan was repeated in each patient after 5 weeks of treatment. Prostate motion was assessed by comparing early to late scans by three methods: 1) center of mass shift, 2) superior pubic symphysis to anterior prostate distance, and 3) deviation of the posterior surface of the prostate.

RESULTS

For prostate (P) or prostate/seminal vesicle (P/SV) treatments, prone flat was advantageous or equivalent to other positions with regard to rectal sparing. The mechanism of rectal sparing in the prone position may be related to a paradoxical retraction of the rectum against the sacrum, away from the P/SV. Although there was no clear overall preference for beam arrangement, substantial improvements in rectal sparing could be realized for individual patients. In this limited number of patients, there was no convincing evidence prostate position was stabilized by prone relative to supine position.

CONCLUSIONS

Prone flat positioning was advantageous over other positions and beam arrangements in rectal sparing. This study suggests that patient position is a more critical a factor in conformal therapy than beam arrangement, and may improve the safety of dose escalation.

Radiation therapy for clinically localized prostate cancer: a multi-institutional pooled analysis

CONTEXT

Prostate-specific antigen (PSA) evaluation leads to the early detection of both prostate cancer and recurrences following primary treatment. Prostate-specific antigen outcome information on patients 5 or more years following treatment is limited and available mainly as single-institution reports.

OBJECTIVES

To assess the likelihood and durability of tumor control using PSA evaluation 5 or more years after radical external beam radiation therapy and to identify pretreatment prognostic factors in men with early prostate cancer treated since 1988, the PSA era.

DESIGN AND SETTING

Retrospective, nonrandomized, multi-institutional pooled analysis of patients treated with external beam radiation therapy alone between 1988 and 1995 at 6 US medical centers. Follow-up lasted up to a maximum of 9 years. Outcome data were analyzed using Cox regression and recursive partitioning techniques.

PATIENTS

A total of 1765 men with stage T1b, T1c, and T2 tumors treated between 1988 and 1995 with external beam radiation. The majority (58%) of patients were older than 70 years and 24.2% had initial PSA values of 20 ng/mL or higher. A minimum of 2 years of subsequent follow-up was required for participation.

MAIN OUTCOME MEASURE

Actuarial estimates of freedom from biochemical failure.

RESULTS

The 5-year estimates of overall survival, disease-specific survival, and the freedom from biochemical failure are 85.0% (95% confidence interval [CI], 82.5%-87.6%), 95.1% (95% CI, 94.0%-96.2%), and 65.8% (95% CI, 62.8%-68.0%), respectively. The PSA failure-free rates 5 and 7 years after treatment for patients presenting with a PSA of less than 10 ng/mL were 77.8% (95% CI, 74.5%-81.3%), and 72.9% (95% CI, 67.9%-78.2%). Recursive partitioning analysis of initial PSA level, palpation stage, and the Gleason score groupings yielded 4 separate prognostic groups: group 1, included patients with a PSA level of less than 9.2 ng/mL; group 2, PSA level of at least 9.2 but less than 19.7 ng/mL; group 3, PSA level at least 19.7 ng/mL and a Gleason score of 2 to 6; and group 4, PSA level of at least 19.7 ng/mL and a Gleason score of 7 to 10. The estimated rates of survival free of biochemical failure at 5 years are 81 % for group 1, 69% for group 2, 47% for group 3, and 29% for group 4. Of the 302 patients followed up beyond 5 years who were free of biochemical disease, 5.0% relapsed from the fifth to the eighth year.

CONCLUSIONS

Estimated PSA control rates in this pooled analysis are similar to those of single institutions. These rates indicate the probability of success for subsets of patients with tumors of several prognostic category groupings. These results represent a multi-institutional benchmark for evidence-based counseling of prostate cancer patients about radiation treatment.

The treatment planning of segmental, conformal stereotactic radiosurgery utilizing a standard multileaf collimator

Over a period of approximately 3 years, our institution has implemented and refined a system of Stereotactic Radiosurgery (SRS) which utilizes the standard multi leaf collimator (MLC) of the Scanditronix MM50 Racetrack Microtron and treats in an arrangement of segmental "pseudo-arcs." This system employs a commercial BRW based stereotactic frame which is mounted to the treatment table. With the exception of the table-mounted frame hardware there have been no modifications to the treatment machine to accommodate these treatments. By use of standard evaluation parameters (e.g., treatment time, planning time, dose conformance and dose heterogeneity ratios) this system compares quite favorably with reported data from institutions treating SRS with either a GammaKnife or a standard linear accelerator with tertiary collimators.

Patterns of failure following high-dose 3-D conformal radiotherapy for high-grade astrocytomas: a quantitative dosimetric study

PURPOSE

To analyze the failure patterns for patients with high-grade astrocytomas treated with high-dose conformal radiotherapy (CRT) using a quantitative technique to calculate the dose received by the CT- or MR-defined recurrence volume and to assess whether the final target volume margin used in the present dose escalation study requires redefinition before further escalation.

METHODS AND MATERIALS

Between 4/89 and 10/95, 71 patients with high-grade supratentorial astrocytomas were entered in a phase I/II dose escalation study using 3-D treatment planning and conformal radiotherapy. All patients were treated to either 70 or 80 Gy in conventional daily fractions of 1.8-2.0 Gy. The clinical and planning target volumes (CTV, PTV) consisted of successively smaller volumes with the final PTV defined as the enhancing lesion plus 0.5 cm margin. As of 10/95, 47 patients have CT or MR evidence of disease recurrence/progression. Of the 47 patients, 36 scans obtained at the time of recurrence were entered into the 3-D radiation therapy treatment planning system. After definition of the recurrent tumor volumes, the recurrence scan dataset was registered with the pretreatment CT dataset so that the actual dose received by the recurrent tumor volumes during treatment could be accurately calculated and then analyzed dosimetrically using dose-volume histograms. Recurrences were divided into several categories: 1) "central," in which 95% or more of the recurrent tumor volume (Vrecur) was within D95, the region treated to high dose (95% of the prescription dose); 2) "in-field," in which 80% or more of Vrecur was within the D95 isodose surface; 3) "marginal," when between 20 and 80% of Vrecur was inside the D95 surface; 4) "outside," in which less than 20% of Vrecur was inside the D95 surface.

RESULTS

In 29 of 36 patients, a solitary lesion was seen on recurrence scans. Of the 29 solitary recurrences, 26 were central, 3 were marginal, and none were outside. Multiple recurrent lesions were seen in seven patients: three patients had multiple central and/or in-field lesions only, three patients had central and/or in-field lesions with additional small marginal or outside lesions, and one patent had 6 outside and one central lesion. Since total recurrence volume was used in the final analysis, 6 of the 7 patients with multiple recurrent lesions were classified into centra/in-field category.

CONCLUSION

Analysis of the 36 evaluable patients has shown that 32 of 36 patients (89%) failed with central or in-field recurrences, 3/36 (8%) had a significant marginal component to the recurrence, whereas only 1/36 (3%) could be clearly labeled as failing mainly outside the high-dose region. Seven patients had multiple recurrences, but only 1 of 7 had large-volume recurrences outside the high-dose region. This study shows that the great majority of patient recurrences that occur after high-dose (70 or 80 Gy) conformal irradiation are centrally located: only 1/36 patients (with 7 recurrent lesions) had more than 50% of the recurrence volume outside the region previously treated to high dose. Further dose escalation to 90 Gy (and beyond) thus seems reasonable, based on the same target volume definition criteria

Optimization and clinical use of multisegment intensity-modulated radiation therapy for high-dose conformal therapy

Intensity-modulated radiation therapy (IMRT) may be performed with many different treatment delivery techniques. This article summarizes the clinical use and optimization of multisegment IMRT plans that have been used to treat more than 350 patients with IMRT over the last 4.5 years. More than 475 separate clinical IMRT plans are reviewed, including treatments of brain, head and neck, thorax, breast and chest wall, abdomen, pelvis, prostate, and other sites. Clinical planning, plan optimization, and treatment delivery are summarized, including efforts to minimize the number of additional intensity-modulated segments needed for particular planning protocols. Interactive and automated optimization of segmental and full IMRT approaches are illustrated, and automation of the segmental IMRT planning process is discussed.

Controversies in the management of stage I seminoma

Current controversies in the treatment of stage I seminoma center on the relative roles of surveillance, adjuvant radiotherapy (RT), and adjuvant single-agent chemotherapy. Surveillance has been studied in over 800 patients, 17.1% of whom have relapsed. There is no evidence that surveillance compromises survival in properly selected, compliant patients. The economic benefit of treating only those patients who relapse is offset by the cost of screening diagnostic studies and salvage therapy, and by issues of patient anxiety and compliance. Other methods of reducing the toxicity of RT include reductions in RT dose and volume. A randomized trial has shown that omission of the pelvic field produces relapse-free survival equivalent to that achieved with pelvic plus para-aortic RT. A similar study is currently evaluating a reduction in RT dose from 30 to 20 Gy. Early results from nonrandomized studies of one or two cycles of single-agent chemotherapy demonstrate efficacy comparable to RT in the adjuvant treatment of stage I seminoma. A randomized trial is underway to determine the equivalence of adjuvant carboplatin (Paraplatin) and RT. Long-term follow-up from these studies will provide information not only on the relative efficacy of these alternative strategies but also on the late effects of therapy, including infertility and second malignancy.

A brain tumor dose escalation protocol based on effective dose equivalence to prior experience

PURPOSE

The current study describes the design of a dose escalation protocol for conformal irradiation of primary brain tumors that preserves the safe experience of a previous, sequential dose escalation scheme while enabling the delivery of substantially higher effective doses to a central target volume.

METHODS AND MATERIALS

Normalized isoeffective composite dose distributions were formed for 20 patients treated on the original protocol (which specified three progressively smaller planning target volumes [PTVs]) using the linear quadratic model (here corrected to equivalent 2 Gy fractions using alpha/beta=10 Gy). These distributions were investigated and a new protocol was designed to preserve a similar level of efficacy and lack of toxicity for the outer volumes, but allowing a higher dose to the inner PTV. Treatment plans were then investigated to determine if the objectives of the new protocol were achievable. In particular, plans that simultaneously achieved all biological treatment planning objectives (all fields treated each day) were investigated. Finally, the success of the protocol design was demonstrated by analysis of the effective dose distributions of 10 patients treated using the new protocol.

RESULTS

The composite normalized isoeffective minimum doses to the outer PTVs (PTV3 and PTV2) in the original protocol were close to 60 Gy and 75 Gy, respectively, and these values are specified as the minimum doses to those volumes for the new protocol. Homogeneity requirements to maintain equivalence for the outer target volume domains are: not more than 25% of [PTV3 exclusive of PTV2] >75 Gy; and not more than 50% of [PTV2 exclusive of PTV1] >85 Gy. Treatment plans using multiple noncoplanar arrangements of beams and static intensity modulation treat all volumes at each session. DVHs of the normalized isoeffective dose distributions reveal the equivalence of the new protocol plans to the sequential plans in the previous protocol as well as the ability to achieve a higher dose of 90 Gy to the isocenter of PTV1 (+/-5% homogeneity required).

CONCLUSION

The ability to incorporate past experience through use of the linear quadratic model in the design of a new dose escalation protocol is demonstrated.

Patterns of failure following treatment for medulloblastoma: is it necessary to treat the entire posterior fossa?

PURPOSE

Craniospinal radiation (CSRT) followed by a boost to the entire posterior fossa (PF) is standard postoperative therapy for patients with medulloblastoma. A large proportion of recurrences after treatment are local, with approximately 50-70% of recurrences occurring in the PF. It is unclear, however, whether these failures are occurring in the original tumor bed or outside the tumor bed, but still within the PF. With improved diagnostic imaging, better definition of tumor volumes, and the use of three-dimensional conformal therapy (3D CRT), we may be able to restrict the boost volume to the tumor bed plus a margin without compromising local control. This retrospective study analyzes the patterns of failure within the PF in a series of patients treated with radiation therapy (RT).

METHODS

From July 1986 through February 1996, 114 patients >18 months and <18 years with medulloblastoma were treated at the University of Michigan and Children's Hospital of Philadelphia, with RT following surgical resection. Of 114, 27 (24%) were found to have a recurrence and form the basis for this study. RT consisted of CSRT followed by a boost to the entire posterior fossa. Some patients received adjuvant chemotherapy. Patient's preoperative magnetic resonance imaging (MRI) and/or computerized tomography (CT) studies were used to compare the original tumor volume with the specific region of local relapse. Failure was defined as MRI or CT evidence of recurrence or positive cerebrospinal fluid cytology. Relapse was scored as local, if it was within the original tumor bed, and regional if it was outside of the tumor bed but still within the PF.

RESULTS

The median age of the 27 patients who relapsed was 8.6 years. Three patients were <3 years old. Of 27, 21 had disease localized to the PF. Of 26, 22 patients received chemotherapy during their treatment regimen; 1 patient did not have information on systemic treatment. The median dose of RT to the craniospinal axis was 32.5 Gy and to the PF was 55.2 Gy. The median time to recurrence was 19.5 months. Local failure within the tumor bed as any component of first failure occurred in 52% (14 of 27) of all failures, but as the solitary site of first failure in only 2 of 27 failures. Of 14 patients who failed in the tumor bed, 11 also failed in the spine, 8 of 14 also failed within the PF but outside the tumor bed, and 7 of 14 failed in all three locations. Local failure within the PF but outside the tumor bed as any component of first failure occurred in 41% (11 of 27) of all failures, but as the solitary site of first failure in only 1 of 27 failures. Of 11 patients who failed in the PF but outside the tumor bed, 9 also failed in the spine, 8 also failed within the tumor bed, and 7 failed in the all three locations. Of the failures outside the tumor bed but still within the PF, 7 of 11 failed in the leptomeninges, 1 in the brainstem parenchyma, and 3 in the PF parenchyma. Of 7 who failed in the PF leptomeninges, 6 also failed within the spine. Failure within the spine as any component of first failure occurred in 70% (19 of 27) of all failures and as the only site of first failure in 5 of 27 patients. Of 19 patients who failed in the spine, 11 also failed in the tumor bed, 9 also failed within the PF but outside the tumor bed, and 9 failed in the all three locations.

CONCLUSIONS

Leptomeningeal failure is a common component of failure and occurs in the leptomeninges of the PF, as well as the spine. Isolated tumor bed failure is a rarely observed event and occurred in only 2 of 27 failures described here. Similarly, parenchymal (nonleptomeningeal) failures in the PF but outside of the tumor bed were rare: 4 patients recurred in this manner, only 1 of whom was an isolated event without other sites of recurrence. Our data suggest that, when the entire PF is treated, very few failures develop in isolation in the PF outside the tumor bed. Further studies will be necessary to determine if RT to the tu

The use of 3D conformal radiotherapy (3D CRT) to spare the cochlea in patients with medulloblastoma

PURPOSE

Radiation therapy in combination with cis-platinum chemotherapy is associated with ototoxicity due to destruction of cochlear hair cells. This is a significant problem, especially in pediatric patients, because it may lead to difficulties with communication, speech, language, and development of learning skills. The use of 3D conformal radiotherapy (3D CRT) may be useful in sparing auditory structures. This paper discusses a technique using 3D CRT to spare the cochlea in patients with medulloblastoma.

METHODS AND MATERIALS

Five pediatric patients with medulloblastoma were planned using 3D CRT. All had MRI and CT obtained specifically for treatment planning. Multiple structures were contoured, including the cochlea and posterior fossa, and conformal beams designed in beam's eye view and dose distribution analysis were edited to provide 3D dose coverage to the target while sparing the inner ear. Patients received 36 Gy to the craniospinal axis followed by an 18-20 Gy boost to the posterior fossa.

RESULTS

A 3D CRT cochlear sparing technique was designed, using an axial pair of posterior oblique fields to treat the posterior fossa while sparing the cochlea for all patients in this analysis. Dose-volume information, obtained from 3D calculations, demonstrates that the average dose received by the cochlea was 65% of the prescribed dose using the cochlear sparing plan, as compared to 101% using standard opposed-lateral beams. Both plans delivered > or = 100% of the prescribed dose to the posterior fossa.

CONCLUSION

3D CRT allows for cochlear sparing in the treatment of medulloblastoma. Further follow-up is necessary to determine the long-term benefit in these patients.

A single plan approach for differentially dosing sequential target volumes

An in-house protocol for treatment of malignant astrocytomas requires development of a single treatment plan constructed to deliver different doses to three sequential target volumes. This single plan approach fundamentally differs from a previous protocol in which these sequential volumes were approached with three consecutive treatment plans, each tailored to a separate target, with the final target receiving a cumulative dose of 80 Gy. The intent of the revised protocol is to deliver doses to the two larger targets that are biologically equivalent (using the linear quadratic model) to the cumulative doses received by these targets in the earlier protocol, while escalating the final target dose to 90 Gy. This requires the treatment planner to manipulate the conformation of three different isodose levels simultaneously to produce a treatment plan fulfilling all protocol specifications. This paper will focus on the evolution of design for the current technique used to clinically implement this protocol.

Pituitary irradiation is ineffective in normalizing plasma insulin-like growth factor I in patients with acromegaly

Pituitary irradiation suppresses GH hypersecretion in patients with acromegaly. Within 10 yr after radiotherapy, up to 80% of patients achieve plasma GH levels below 5 micrograms/L. Whether this is sufficient to normalize plasma insulin-like growth factor I (IGF-I) levels, is unknown. We examined the effect of radiotherapy on plasma IGF-I concentrations in patients with acromegaly. We reviewed hospital charts of 140 patients with acromegaly seen in our institution between 1975 and 1996. Data on plasma GH and IGF-I were extracted and tabulated longitudinally together with the information about the concomitant medical therapy. We included data from the patients who received radiotherapy as a part of their treatment and whose IGF-I was monitored for more than 1 yr afterward. To avoid the potential bias, the data for patients who were referred to us for medical therapy, having failed radiation elsewhere, were excluded. A total of 38 datasets were submitted for the final analysis. The average follow-up was 6.8 +/- 0.8 yr (range, 1-19). Only 2 patients achieved age- and sex-adjusted normal IGF-I levels while off medical therapy. Noncured patients had a mean plasma GH level of 4.6 +/- 1.1 micrograms/L but still elevated plasma IGF-I levels (219 +/- 26% of the upper normal limit) at the last follow-up visit. A random GH concentration below 1.5 micrograms/L was associated with a pathologically high plasma IGF-I concentration in 43% of instances. Radiotherapy appears to be ineffective in normalizing plasma IGF-I levels in acromegaly. A multicenter study to reevaluate the future use of this modality in patients with acromegaly is warranted.

Results of re-irradiation of primary intracranial neoplasms with three-dimensional conformal therapy

We evaluated the potential of three-dimensional conformal therapy for re-irradiation of selected intracranial neoplasms and reviewed the retreatment of 20 patients at the University of Michigan between May 1988 and August 1991. All patients had previously undergone a full course of external beam radiotherapy (RT) to a median dose of 5,940 cGy (range 5,100-6,500 cGy), including five whole brain treatments. All recurrences were unsuitable for brachytherapy or radiosurgery. Various histologies were retreated, including 14 high-grade gliomas. Median time to re-irradiation was 38 months (range 9 months to 19 years, 6 months). RT was delivered with complex plans designed using fully integrated computed tomography/magnetic resonance imaging (CT/ MRI) tumor volume information, and regions of previous parenchymal treatment were avoided if possible. Composite (initial+retreatment) dose-volume histograms (DVH) of dose to nontarget brain allowed comparison of alternative plans to select beam orientations which minimized normal brain irradiation. Mean target dose of re-irradiation was 3,600 cGy (range 3,060-5,940 cGy). Total cumulative dose ranged from 8,060 to 11,940 cGy. Median survival was 9 months, and 1-year actuarial survival was 26%. After retreatment, 8 of 12 patients (67%) had steroid dose decrement and neurologic improvement at 4-48 months (median duration 14 months). Radiographic regression or stabilization of disease was noted in 11 of 16 patients (68%). Re-irradiation with highly conformal three-dimensional planning provides frequent clinical improvement with acceptable morbidity and should be considered in selected patients with recurrent intracranial neoplasms.

Rate of PSA rise predicts metastatic versus local recurrence after definitive radiotherapy

OBJECTIVE

A rising prostate specific antigen (PSA) following treatment for adenocarcinoma of the prostate indicates eventual clinical failure, but the rate of rise can be quite different from patient to patient, as can the pattern of clinical failure. We sought to determine whether the rate of PSA rise could differentiate future local versus metastatic failure.

METHODS AND MATERIALS

Two thousand six hundred sixty-seven PSA values from 400 patients treated with radiotherapy for localized adenocarcinoma of the prostate were analyzed with respect to PSA patterns and clinical outcome. Patients had received no hormonal therapy or prostate surgery and had > 4 PSA values post-treatment. PSA rate of rise, determined by the slope of the natural log, was classified as gradual [< 0.69 log(ng/ml)/year, or doubling time (DT) > 1 year], moderate [0.69-1.4 log(ng/ml)/year, or DT 6 months-1 year], or rapid [> 1.4 log(ng/ml)/year, or DT < 6 months].

RESULTS

Sixty-one percent of patients had non-rising PSA following treatment; 25% of patients with rising PSA developed clinical failure, and 93% of patients with clinical failure had rising PSA. The rate of rise discerned different clinical failure patterns. Local failure occurred in 23% of patients with moderate rate of rise versus 7% with gradual rise (p = 0.0001). Metastatic disease developed in 46% of those with rapid rise versus 8% with moderate rise (p < 0.0001). By multivariate analysis, in addition to rate of rise, PSA nadir and rate of decline predicted local failure; those with post-treatment nadir of 1-4 ng/ml were five times more likely to experience local failure than nadir < 1 ng/ml (p = 0.0002). Rapid rate of rise was the most significant independent predictor of metastatic failure.

CONCLUSIONS

The rate of PSA rise following definitive radiotherapy can predict clinical failure patterns, with a rapidly rising PSA indicating metastatic recurrence and moderately rising PSA local recurrence. This information could potentially direct therapy; if the rise predicts metastatic failure hormonal therapy could be considered, while aggressive salvage therapy may benefit subclinical local recurrence identified by a moderate rate of PSA rise.