Estimating the impact of randomised control trial results on clinical practice: results from a survey and modelling study of androgen deprivation therapy plus radiotherapy for locally advanced prostate cancer

Background Recent trials have shown that the addition of external beam radiotherapy (EBRT) to androgen deprivation therapy (ADT) improves survival among men with locally advanced prostate cancer. Objective To examine the potential impact of these trials on changes in clinical practice and life-years saved. Design, setting, and participants A model was developed to examine the impact of changes in clinical practice in the UK. A survey of clinicians who treat men with prostate cancer in the UK and Canada was performed. Measurements Outcomes of interest were the proportion of patients treated with different approaches and the predicted number of life-years saved due to changes in clinical practice. Survey data were cross-tabulated and Pearson's χ2 tests were applied. Results and limitations The survey was completed by 193 clinicians (105 from the UK, 80 from Canada), of whom 70% were clinical/radiation oncologists, 8% were medical oncologists, and 15% were urologists. UK respondents were more likely to report a change in practice in response to the results (44% UK vs 21% Canada). Canadians were more likely to have already been using ADT plus radiotherapy (77% Canada vs 56% UK). The increase in the proportion of patients in the UK treated with ADT + EBRT could result in around 3730–5177 extra life-years at 15 yr from a cohort of 7930 men diagnosed in a single calendar year, compared to if all had been treated with ADT alone. Conclusions Trial findings have changed clinical practice, meaning that men with locally advanced prostate cancer are likely to survive longer. Patient summary Doctors in the UK have changed practice in response to evidence on the superiority of hormone therapy plus radiotherapy to hormone therapy alone. These changes will improve the survival of men with locally advanced prostate cancer. Further reductions in the use of hormone therapy alone could further improve survival

Salvage radiotherapy after radical prostatectomy: analysis of toxicity by dose-fractionation in the RADICALS-RT trial

ABSTRACT: Emerging data indicate comparable disease control and toxicity of postoperative normo-fractionation and moderate hypofractionation radiotherapy (RT) in prostate cancer. In RADICALS-RT, patients were planned for treatment with either 66Gy in 33 fractions over 6.5 weeks or 52.5Gy in 20 fractions over 4 weeks. In this non-randomized, exploratory analysis, we explore the toxicity of these two schedules in patients who had adjuvant RT. METHODS: Information on RT dose was collected in all patients. Radiation Therapy Oncology Group toxicity score was recorded every 4 months for 2 years, 6-monthly until 5 years, then annually until 15 years. Patient-reported data were collected at baseline, 1, 5, and 10 years with use of standard questionnaires including Vaizey (bowel) and International Continence Society Male Short-Form (urinary incontinence). The highest grade of event was recorded within the first 2 years, and beyond 2 years, and compared between treatment groups using the χ² test. RESULTS: 217/634 (34%) patients were planned for 52.5Gy/20f and 417/634 (66%) for 66Gy/33f. In the first two years, grade 1 - 2 cystitis was reported more frequently among the 66Gy/33f group (52.5Gy/20f: 20% vs 66Gy/33f: 30%, p=0.04). After two years, grade 1-2 cystitis was reported in 16% in the 66Gy group, and 9% in the 52.5Gy group (p=0.08). Other toxicities were similar in the two groups and very few patients had any grade 3 - 4 toxicity. Patients reported slightly higher urinary and faecal incontinence scores at one year than at baseline, but no clinically meaningful differences were reported between 52.5Gy/20f and 66Gy/33f groups. Patient reported health was similar at baseline and at one year, and similar between 52.5Gy/20f and 66Gy/33f groups. CONCLUSION: Severe toxicity is rare after prostate bed radiotherapy with either 52.5Gy/20f or 66Gy/33f. Only modest differences were recorded in toxicity or in patient reported outcomes between these two schedules

Re: Final Report of the Intergroup Randomized Study of Combined AndrogenDeprivation Therapy Plus Radiotherapy Versus Androgen-Deprivation Therapy Alone in Locally Advanced Prostate Cancer

No certain treatment recommendations were given for locally advanced or high-risk prostate cancer in the European Association of Urology (EAU) guidelines (1). In the guidelines, studies supporting surgery or radiotherapy (RT) were listed, and the readers were left alone to make their own decisions. In the present study, Mason et al. reported the impact of adding RT to androgen deprivation therapy (ADT). One thousand two hundred and five patients with T3- 4, N0/Nx, M0 prostate cancer or T1-2 disease with either PSA more than 40 μg/L or PSA 20 to 40 μg/L plus Gleason score of 8 to 10 were randomized to ADT alone (n=602) or to ADT+RT (n=603). A lower dose radiation 64 to 69 Gy was used for RT. Overall survival (OS) risk reduction was 30% for ADT+RT group (P<0.001) at a median follow-up of 8 years. Cancer-specific survival (CSS) was significantly improved by the addition of RT to ADT (HR: 0.46, 95% CI: 0.34 to 0.61; p<0.001). Patients on ADT+RT reported a higher frequency of adverse events related to bowel toxicity. However, reported frequency of ADT-related toxicities (impotence, hot flushes, urinary frequency, ischemia, and hypertension) were similar for both arms. The present study provided results of high-risk patients in a longer median follow-up time than SPCG-7 study (2). Because the study took place between 1995 and 2005, less than 70 Gy was used for RT. Even at lower radiation doses, the authors confirmed that adding RT to ADT improved both OS and cancer-specific survival (CSS) with minimal general toxicity. In the modern era, improved RT techniques may help achieve better outcomes with much higher radiation doses without increased morbidity in this group of patient

A Novel Biomarker Panel Examining Response to Gemcitabine with or without Erlotinib for Pancreatic Cancer Therapy in NCIC Clinical Trials Group PA.3.

PURPOSE:NCIC Clinical Trials Group PA.3 was a randomized control trial that demonstrated improved overall survival (OS) in patients receiving erlotinib in addition to gemcitabine for locally advanced or metastatic pancreatic cancer. Prior to therapy, patients had plasma samples drawn for future study. We sought to identify biomarkers within these samples. EXPERIMENTAL DESIGN:Using the proximity ligation assay (PLA), a probe panel was built from commercially available antibodies for 35 key proteins selected from a global genetic analysis of pancreatic cancers, and used to quantify protein levels in 20 uL of patient plasma. To determine if any of these proteins levels independently associated with OS, univariate and mulitbaraible Cox models were used. In addition, we examined the associations between biomarker expression and disease stage at diagnosis using Fisher's exact test. The correlation between Erlotinib sensitivity and each biomarkers was assessed using a test of interaction between treatment and biomarker. RESULTS AND CONCLUSION:Of the 569 eligible patients, 480 had samples available for study. Samples were randomly allocated into training (251) and validation sets (229). Among all patients, elevated levels of interleukin-8 (IL-8), carcinoembryonic antigen (CEA), hypoxia-inducible factor 1-alpha (HIF-1 alpha), and interleukin-6 were independently associated with lower OS, while IL-8, CEA, platelet-derived growth factor receptor alpha and mucin-1 were associated with metastatic disease. Patients with elevated levels of receptor tyrosine-protein kinase erbB-2 (HER2) expression had improved OS when treated with erlotinib compared to placebo. In conclusion, PLA is a powerful tool for identifying biomarkers from archived, small volume serum samples. These data may be useful to stratify patient outcomes regardless of therapeutic intervention. TRIAL REGISTRATION:ClinicalTrials.gov NCT00040183