Patrick Cheung

Palliative Thoracic Radiotherapy for Lung Cancer: A Systematic Review

PURPOSE The optimal dose of radiotherapy (RT) to palliate symptomatic advanced lung cancer is unclear. We systematically reviewed randomized controlled trials (RCTs) of palliative thoracic RT. METHODS RCTs comparing two or more dose fractionation schedules were reviewed using the random-effects model of a freely available information management system. The relative risk and 95% CI for each outcome were presented in Forrest plots. Exploratory analysis comparing dose schedules after conversion to the time-adjusted biologically equivalent dose (BED) was performed to investigate for a dose-response relationship. RESULTS A total of 13 RCTs involving 3,473 randomly assigned patients were identified. Outcomes included symptom palliation, overall survival, toxicity, and reirradiation rate. For symptom control in assessable patients, lower-dose (LD) RT was comparable with higher-dose (HD), except for the total symptom score (TSS): 65.4% of LD and 77.1% of HD patients had improved TSS (P = .003). Greater likelihood of symptom improvement was seen with schedules of 35 Gy(10) versus lower BED. At 1 year after HD and LD RT, 26.5% versus 21.7% of patients were alive, respectively (P = .002). Sensitivity analysis suggests this survival improvement was seen with 35 Gy(10) BED schedules compared with LDs. Physician-assessed dysphagia was significantly greater in the HD arm (20.5% v 14.9%; P = .01), and the likelihood of reirradiation was 1.2-fold higher after LD RT. CONCLUSION No significant differences were observed for specific symptom-control end points, although improvement in survival favored HD RT. Consideration of palliative thoracic RT of at least 35 Gy(10) BED may therefore be warranted, but must be weighed against increased toxicity and greater time investment.

Prostate stereotactic ablative body radiotherapy using a standard linear accelerator: Toxicity, biochemical, and pathological outcomes

BACKGROUND AND PURPOSE Biological dose escalation through stereotactic ablative radiotherapy (SABR) holds promise of improved patient convenience, system capacity and tumor control with decreased cost and side effects. The objectives are to report the toxicities, biochemical and pathologic outcomes of this prospective study. MATERIALS AND METHODS A phase I/II study was performed where low risk localized prostate cancer received SABR 35 Gy in 5 fractions, once weekly on standard linear accelerators. Common Terminology Criteria for Adverse Events v3.0 and Radiation Therapy Oncology Group late morbidity scores were used to assess acute and late toxicities, respectively. Biochemical control (BC) was defined by the Phoenix definition. RESULTS As of May 2012, 84 patients have completed treatment with a median follow-up of 55 months (range 13-68 months). Median age was 67 years and median PSA was 5.3 ng/ml. The following toxicities were observed: acute grade 3+: 0% gastrointestinal (GI), 1% genitourinary (GU), 0% fatigue; late grade 3+: 1% GI, 1% GU. Ninety-six percent were biopsy negative post-treatment. The 5-year BC was 98%. CONCLUSIONS This novel technique employing standard linear accelerators to deliver an extreme hypofractionated schedule of radiotherapy is feasible, well tolerated and shows excellent pathologic and biochemical control.

Assessing the role of volumetric modulated arc therapy (VMAT) relative to IMRT and helical tomotherapy in the management of localized, locally advanced, and post-operative prostate cancer.

PURPOSE To quantify differences in treatment delivery efficiency and dosimetry between step-and-shoot intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT) for prostate treatment. METHODS AND MATERIALS Twenty-five prostate cancer patients were selected retrospectively for this planning study. Treatment plans were generated for: prostate alone (n = 5), prostate + seminal vesicles (n = 5), prostate + seminal vesicles + pelvic lymph nodes (n = 5), prostate bed (n = 5), and prostate bed + pelvic lymph nodes (n = 5). Target coverage, dose homogeneity, integral dose, monitor units (MU), and sparing of organs at risk (OAR) were compared across techniques. Time required to deliver each plan was measured. RESULTS The dosimetric quality of IMRT, VMAT, and HT plans were comparable for target coverage (planning target volume V95%, clinical target volume V100% all >98.7%) and sparing of organs at risk (OAR) for all treatment groups. Although HT resulted in a slightly higher integral dose and mean doses to the OAR, it yielded a lower maximum dose to all OAR examined. VMAT resulted in reductions in treatment times over IMRT (mean = 75%) and HT (mean = 70%). VMAT required 15-38% fewer monitor units than IMRT over all treatment volumes, with the reduction per fraction ranging from 100-423 MU from the smallest to largest volumes. CONCLUSIONS VMAT improves efficiency of delivery for equivalent dosimetric quality as IMRT and HT across various prostate cancer treatment volumes in the intact and postoperative settings.

Is single fraction 15 Gy the preferred high dose-rate brachytherapy boost dose for prostate cancer?

BACKGROUND AND PURPOSE High dose-rate (HDR) brachytherapy is most commonly administered as a boost in two or more fractions combined with external beam radiotherapy (EBRT). Our purpose is to compare outcomes with a single fraction HDR boost to that with a standard fractionated boost in intermediate risk prostate cancer. MATERIALS AND METHODS Results of two sequential phase II clinical trials are compared. The Single Fraction protocol consists of 15 Gy HDR in one fraction followed by 37.5 Gy EBRT in 15 fractions over 3 weeks; the Standard Fractionation protocol consisted of two HDR fractions each of 10 Gy, 1 week apart, followed by 45 Gy EBRT in 25 fractions. Patients had intermediate risk disease, and were well balanced for prognostic factors. Patients were followed prospectively for efficacy, toxicity and health-related quality of life (Expanded Prostate Index Composite). Efficacy was assessed biochemically using the Phoenix definition, and by biopsy at 2 years. RESULTS The Single Fraction protocol accrued 123 patients and the Standard Fractionation protocol, 60. With a median follow-up of 45 and 72 months, respectively, the biochemical disease-free survival was 95.1% and 97.9% in the Single and Standard Fractionation trials (p=0.3528). Two-year prostate biopsy was positive in only 4% and 8%, respectively. There was no difference in late urinary or rectal toxicity rates, or in health-related quality of life between the two protocols. CONCLUSIONS The Single Fraction HDR protocol results in high disease control rate and low toxicity similar to our previous protocol using two HDR insertions, with significant savings in resources. While mature results with longer follow-up are awaited, a single 15 Gy may be considered as a standard fractionation regimen in combination with EBRT for men with intermediate risk disease.

Single-Fraction High-Dose-Rate Brachytherapy and Hypofractionated External Beam Radiotherapy for Men With Intermediate-Risk Prostate Cancer: Analysis of Short- and Medium-Term Toxicity and Quality of Life

PURPOSE To determine the short- and medium-term effects of a single high-dose-rate brachytherapy fraction of 15 Gy and hypofractionated external beam radiation therapy for prostate cancer. METHODS AND MATERIALS Eligible patients had localized prostate cancer with a Gleason score of 7 and a prostate-specific antigen (PSA) concentration of <20 ng/ml or a Gleason score of 6 with a PSA concentration of 10 to 20 ng/ml. Patients received high-dose-rate brachytherapy as a single 15-Gy dose, followed by external beam radiation therapy at 37.5 Gy in 15 fractions, and were followed prospectively for toxicity (using Common Terminology Criteria for Adverse Events version 3.0), urinary symptoms (using the International Prostate Symptom Score [IPSS]), erectile function (with the International Index of Erectile Function [IIEF]), and health-related quality of life (with the Expanded Prostate Cancer Index Composite [EPIC]). Clinical examinations and PSA measurements were performed at every visit, and prostate biopsies were repeated at 2 years. The trial accrued 125 patients, with a median follow-up of 1.14 years. RESULTS Acute grade 2 and 3 genitourinary toxicity occurred in 62% and 1.6% of patients, respectively, and acute grade 2 gastrointestinal toxicity occurred in 6.5% of patients. No grade 3 late toxicity has occurred: 47% of patients had grade 2 genitourinary and 10% of patients had grade 2 gastrointestinal toxicity. Median IPSSs rose from 5 at baseline to 12 at 1 month and returned to 7 at 3 months. Of the total number of patients who were initially potent (IIEF, >21), 8% of patients developed mild to moderate dysfunction, and 27% of patients developed severe erectile dysfunction. Baseline EPIC bowel, urinary, and sexual bother scores decreased by 9, 7, and 19 points, respectively, at 1 year. No patient has experienced biochemical failure, and 16 of the first 17 biopsy results showed no malignancy. CONCLUSIONS Treatment is well tolerated in the short and medium term, with low toxicity and encouraging early indicators of disease control.

Randomized Trial of a Hypofractionated Radiation Regimen for the Treatment of Localized Prostate Cancer

Purpose Men with localized prostate cancer often are treated with external radiotherapy (RT) over 8 to 9 weeks. Hypofractionated RT is given over a shorter time with larger doses per treatment than standard RT. We hypothesized that hypofractionation versus conventional fractionation is similar in efficacy without increased toxicity. Patients and Methods We conducted a multicenter randomized noninferiority trial in intermediate-risk prostate cancer (T1 to 2a, Gleason score ≤ 6, and prostate-specific antigen [PSA] 10.1 to 20 ng/mL; T2b to 2c, Gleason ≤ 6, and PSA ≤ 20 ng/mL; or T1 to 2, Gleason = 7, and PSA ≤ 20 ng/mL). Patients were allocated to conventional RT of 78 Gy in 39 fractions over 8 weeks or to hypofractionated RT of 60 Gy in 20 fractions over 4 weeks. Androgen deprivation was not permitted with therapy. The primary outcome was biochemical-clinical failure (BCF) defined by any of the following: PSA failure (nadir + 2), hormonal intervention, clinical local or distant failure, or death as a result of prostate cancer. The noninferiority margin was 7.5% (hazard ratio, < 1.32). Results Median follow-up was 6.0 years. One hundred nine of 608 patients in the hypofractionated arm versus 117 of 598 in the standard arm experienced BCF. Most of the events were PSA failures. The 5-year BCF disease-free survival was 85% in both arms (hazard ratio [short v standard], 0.96; 90% CI, 0.77 to 1.2). Ten deaths as a result of prostate cancer occurred in the short arm and 12 in the standard arm. No significant differences were detected between arms for grade ≥ 3 late genitourinary and GI toxicity. Conclusion The hypofractionated RT regimen used in this trial was not inferior to conventional RT and was not associated with increased late toxicity. Hypofractionated RT is more convenient for patients and should be considered for intermediate-risk prostate cancer.

Fuels and chemicals from sewage sludge: 2. The production of alkanes and alkenes by the pyrolysis of triglycerides over activated alumina

Abstract Triolein, canola oil, trilaurin and coconut oil were pyrolysed over activated alumina at 450°C and atmospheric pressure. The liquid products were hydrocarbon mixtures which contained both alkanes and alkenes. I.r. spectra confirmed the absence of carbonyl groups in all the pyrolysed products. Decoupled 13 C n.m.r. supported this as well as showing the presence of thermodynamically unfavourable terminal double bonds. These were probably formed by a gamma hydrogen transfer mechanism in which the glycerol moiety together with the ester carbonyl group was lost. There were 14.3, 17.1, 10.1 and 13.4 carbon atoms per double bond, respectively in the liquid products of tiolein, canola oil, trilaurin and coconut oil pyrolysis. Gas chromatography showed some cracking of the hydrocarbon chains with a preference for C6 and C7 products from triolein and canola oil pyrolysis and C9 and C11 products from trilaurin and coconut oil pyrolysis, but otherwise a uniform distribution across the C6 to C16 mass range. These results are significant for the pyrolysis of the lipid fraction which can be isolated by the solvent extraction of sewage sludge, as well as to the pyrolysis of wastes from food processing industries.

Health-Related Quality of Life After Single-Fraction High-Dose-Rate Brachytherapy and Hypofractionated External Beam Radiotherapy for Prostate Cancer

PURPOSE To investigate the change in health-related quality of life for men after high-dose-rate brachytherapy and external beam radiotherapy for prostate cancer and the factors associated with this change. METHODS AND MATERIALS Eligible patients had clinically localized intermediate-risk prostate cancer. The patients received high-dose-rate brachytherapy as a single 15-Gy implant, followed by external beam radiotherapy to 37.5 Gy in 15 fractions. The patients were monitored prospectively for toxicity (Common Terminology Criteria for Adverse Events, version 3.0) and health-related quality of life (Expanded Prostate Cancer Index Composite [EPIC]). The proportion of patients developing a clinically significant difference in the EPIC domain score (minimally important difference of >0.5 standard deviation) was determined and correlated with the baseline clinical and dosimetric factors. The study accrued 125 patients, with a median follow-up of 24 months. RESULTS By 24 months, 23% had Grade 2 urinary toxicity and only 5% had Grade 2 bowel toxicity, with no Grade 3 toxicity. The proportion of patients reporting a significant decrease in EPIC urinary, bowel, sexual, and hormonal domain scores was 53%, 51%, 45%, and 40% at 12 months and 57%, 65%, 51%, and 30% at 24 months, respectively. The proportion with a >1 standard deviation decrease in the EPIC urinary, bowel, sexual, and hormonal domain scores was 38%, 36%, 24%, and 20% at 12 months and 46%, 48%, 19%, and 8% at 24 months, respectively. On multivariate analysis, the dose to 10% of the urethra was associated with a decreasing EPIC urinary domain score (p = .0089) and, less strongly (p = .0312) with a decreasing hormonal domain score. No association was found between the prostate volume, bladder dose, or high-dose volume and urinary health-related quality of life. A high baseline International Index of Erectile Function score was associated (p = .0019) with a decreasing sexual domain score. The optimal maximal dose to 10% of the urethra cutpoint for urinary health-related quality of life was 120% of the prescription dose. CONCLUSION EPIC was a more sensitive tool for detecting the effects on function and bother than were the generic toxicity scales. The urethral dose had the strongest association with a deteriorating urinary quality of life.

Prospective Assessment of Gastrointestinal and Genitourinary Toxicity of Salvage Radiotherapy for Patients With Prostate-Specific Antigen Relapse or Local Recurrence After Radical Prostatectomy

PURPOSE To assess the acute and late gastrointestinal (GI) and genitourinary (GU) toxicity of salvage radiotherapy (RT). METHODS AND MATERIALS A total of 75 patients with prostate-specific antigen relapse or clinically isolated local recurrence after radical prostatectomy were accrued between 1998 and 2002 for a Phase II study to evaluate the efficacy of salvage RT plus 2-year androgen suppression. Acute and late GI and GU toxicity was prospectively assessed using the National Cancer Institute Expanded Common Toxicity Criteria Version 2. For acute toxicity, prevalence was examined. For late toxicity, cumulative incidences of Grade 2 or higher and Grade 3 toxicity were calculated. RESULTS Median age was 67 years at the time of salvage RT. Median time from radical prostatectomy to RT was 36.2 months. Median follow-up was 45.1 months. Seventy-five patients were available for acute toxicity analysis, and 72 for late toxicity. Twelve percent and 40% had preexisting GI and GU dysfunction before RT, respectively. Sixty-eight percent, 21%, and 5% experienced Grade 1, 2, and 3 acute GI or GU toxicity, respectively. Cumulative incidences of Grade 2 or higher late GI and GU toxicity at 36 months were 8.7% and 22.6%, and Grade 3 late GI and GU toxicity, 1.6% and 2.8%, respectively. None had Grade 4 late toxicity. The severity of acute GU toxicity (Grade < 2 vs. >/= 2) was a significant predictor factor for Grade 2 or higher late GU toxicity after adjusting for preexisting GU dysfunction. CONCLUSION Salvage RT generally was well tolerated. Grade 3 or higher late GI or GU toxicity was uncommon.

EFFICACY OF SALVAGE RADIOTHERAPY PLUS 2-YEAR ANDROGEN SUPPRESSION FOR POSTRADICAL PROSTATECTOMY PATIENTS WITH PSA RELAPSE

PURPOSE To determine the efficacy of a combined approach of radiotherapy (RT) plus 2-year androgen suppression (AS) as salvage treatment for prostate-specific antigen (PSA) relapse after radical prostatectomy (RP). METHODS AND MATERIALS Seventy-five patients with PSA relapse after RP were treated with salvage RT plus 2-year AS, as per a pilot, prospective study. AS started within 1 month after completion of salvage RT and consisted of nilutamide for 4 weeks and buserelin acetate depot subcutaneously every 2 months for 2 years. Relapse-free rate including freedom from PSA relapse was estimated using the Kaplan-Meier method. PSA relapse was defined as a PSA rise above 0.2 ng/mL with two consecutive increases over a minimum of 3 months. A Cox regression analysis was performed to evaluate prognostic factors for relapse. RESULTS Median age of the cohort was 63 years at the time of salvage RT. Median follow-up from salvage RT was 6.4 years. All achieved initially complete PSA response (< 0.2) with the protocol treatment. Relapse-free rate including the freedom from PSA relapse was 91.5% at 5 years and 78.6% at 7 years. Overall survival rate was 93.2% at both 5 and 7 years. On Cox regression analysis, pT3 stage and PSA relapse less than 2 years after RP were significant prognostic factors for relapse. CONCLUSION The combined treatment of salvage RT plus 2-year AS yielded an encouraging result for patients with PSA relapse after RP and needs a confirmatory study.