Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

Spectrum of BCR-ABL kinase domain mutations in patients with chronic myeloid leukemia from India with suspected resistance to imatinib-mutations are rare and have different distributions

This article does not have an abstract

Increased ABCG2 Expression Could Be Responsible for Resistance to Imatinib Mesylate in Patients with Chronic Myeloid Leukemia Who Do Not Have Mutations in BCR-ABL Kinase Domain

Abstract Mutation in the Bcr-Abl kinase domain is one of the most common mechanism of resistance to imatinib mesylate (IM), seen in 30– 90% of patients with chronic myeloid leukemia (CML). A total of 57 patients with CML, 41 in chronic phase, 10 in accelerated phase and 6 in blast crisis, were analyzed for bcr-abl kinase domain (KD) mutations using reverse transcriptase polymerase chain reaction (RT-PCR) amplification of the bcr-abl KD followed by direct sequencing. Twelve different mutations including three novel mutations were identified in the bcr-abl KD in 18 patients. Resistance to IM was considered if the patient had rising white blood cell counts or did not achieve hematological remission at 6 months; or had rising bcr-abl levels (as determined by fluorescence in situ hybridization or real-time quantitative PCR) after the start of IM treatment. In order to evaluate other potential mechanisms of resistance in patients without mutations in the bcr-abl kinase domain, we tested the expression levels of transporter genes known to be involved in IM influx and efflux. mRNA expression levels of efflux transporters, ABCG2 and ABCB1, and influx transporter, hOCT1 were measured by real time quantitative PCR using ABL to normalize the expression levels of the same. Serially diluted cDNA made from HepG2 RNA was used to make the standard curve and amplification efficiencies of the target and the house keeping genes were similar. Each sample was analyzed in duplicate and the experiment was repeated twice. In the patients without mutations in the bcr-abl KD, significantly higher ABCG2 mRNA levels were observed compared to patients with mutations (Table). Transcript levels of ABCB1, hOCT1 or bcr-abl were not significantly different between the two groups. This study suggests that over expression of ABCG2 may be one of the mechanisms of resistance to imatinib in patients without mutations in bcr-abl. Future studies should not only compare the expression of these transporters at diagnosis (before the start of IM treatment) but also at the time of clinical resistance. This will help understand the influence of expression levels of these transporters in achieving haematological or molecular response to increased IM doses. Bcr-abl mutation positive (n=18) Bcr-abl mutation negative (n=39) p value ABCG2: median (range) 0.0126 (0.0004–0.45) 0.051 (0.0041–0.51) 0.034 ABCB1: median (range) 0.1842 (0.00349–0.51) 0.1819 (0.0463–0.68) NS hOCT1: median (range) 488 (3.4–3394) 486 (62–3059) NS BCR-ABL: median (range) 53.96 (5.73–179.1) 51.3 (2.36–129) NS</jats:p