W. Lam

Tumour genomic and microenvironmental heterogeneity for integrated prediction of 5-year biochemical recurrence of prostate cancer: a retrospective cohort study

BACKGROUNDnClinical prognostic groupings for localised prostate cancers are imprecise, with 30-50% of patients recurring after image-guided radiotherapy or radical prostatectomy. We aimed to test combined genomic and microenvironmental indices in prostate cancer to improve risk stratification and complement clinical prognostic factors.nnnMETHODSnWe used DNA-based indices alone or in combination with intra-prostatic hypoxia measurements to develop four prognostic indices in 126 low-risk to intermediate-risk patients (Toronto cohort) who will receive image-guided radiotherapy. We validated these indices in two independent cohorts of 154 (Memorial Sloan Kettering Cancer Center cohort [MSKCC] cohort) and 117 (Cambridge cohort) radical prostatectomy specimens from low-risk to high-risk patients. We applied unsupervised and supervised machine learning techniques to the copy-number profiles of 126 pre-image-guided radiotherapy diagnostic biopsies to develop prognostic signatures. Our primary endpoint was the development of a set of prognostic measures capable of stratifying patients for risk of biochemical relapse 5 years after primary treatment.nnnFINDINGSnBiochemical relapse was associated with indices of tumour hypoxia, genomic instability, and genomic subtypes based on multivariate analyses. We identified four genomic subtypes for prostate cancer, which had different 5-year biochemical relapse-free survival. Genomic instability is prognostic for relapse in both image-guided radiotherapy (multivariate analysis hazard ratio [HR] 4·5 [95% CI 2·1-9·8]; p=0·00013; area under the receiver operator curve [AUC] 0·70 [95% CI 0·65-0·76]) and radical prostatectomy (4·0 [1·6-9·7]; p=0·0024; AUC 0·57 [0·52-0·61]) patients with prostate cancer, and its effect is magnified by intratumoral hypoxia (3·8 [1·2-12]; p=0·019; AUC 0·67 [0·61-0·73]). A novel 100-loci DNA signature accurately classified treatment outcome in the MSKCC low-risk to intermediate-risk cohort (multivariate analysis HR 6·1 [95% CI 2·0-19]; p=0·0015; AUC 0·74 [95% CI 0·65-0·83]). In the independent MSKCC and Cambridge cohorts, this signature identified low-risk to high-risk patients who were most likely to fail treatment within 18 months (combined cohorts multivariate analysis HR 2·9 [95% CI 1·4-6·0]; p=0·0039; AUC 0·68 [95% CI 0·63-0·73]), and was better at predicting biochemical relapse than 23 previously published RNA signatures.nnnINTERPRETATIONnThis is the first study of cancer outcome to integrate DNA-based and microenvironment-based failure indices to predict patient outcome. Patients exhibiting these aggressive features after biopsy should be entered into treatment intensification trials.nnnFUNDINGnMovember Foundation, Prostate Cancer Canada, Ontario Institute for Cancer Research, Canadian Institute for Health Research, NIHR Cambridge Biomedical Research Centre, The University of Cambridge, Cancer Research UK, Cambridge Cancer Charity, Prostate Cancer UK, Hutchison Whampoa Limited, Terry Fox Research Institute, Princess Margaret Cancer Centre Foundation, PMH-Radiation Medicine Program Academic Enrichment Fund, Motorcycle Ride for Dad (Durham), Canadian Cancer Society.

Defining Genomic Alteration Boundaries for a Combined Small Cell and Non-small Cell Lung Carcinoma

In the rare case of a male patient presenting with a combined small cell lung carcinoma (SCLC), large cell neuroendocrine carcinoma and adenocarcinoma, we used whole genome analysis by tiling-path array comparative genomic hybridization to evaluate the clonal relationship between nodules. In two areas of SCLC distinguishable by divergent neuroendocrine marker expression (CD56 and chromogranin-A), the presence of identical genomic breakpoints and rearrangements indicated a common origin, with the presence of additional distinct genomic alterations in these two components indicating diverging clonal evolution. The absence of shared genome alteration features for the adenocarcinoma and large cell neuroendocrine carcinoma components suggested that these tumors evolved independently from the SCLC. Taken together, the array comparative genomic hybridization data demonstrate the development and evolution of three independent primary lung cancers in close proximity to each other to form a combined carcinoma. Application of whole genome analysis shows the potential utility of high resolution molecular tools in resolving the origin and delineating the clonal relationships of a tumor that contains heterogeneous histologic components leading to an ambiguous histogenesis.

Use of genetic instability to predict biochemical recurrence in intermediate-risk prostate cancer.

42 Background: Biomarkers of local and systemic recurrence are needed to individualize patient risk categories and better define treatment. We hypothesized that genomic instability, as measured by percent genome alteration (PGA), can predict for biochemical failure in intermediate- risk prostate cancer.nnnMETHODSnHigh-resolution array comparative genomic hybridization (arrayCGH) was used to identify PGA in frozen biopsies from 120 intermediate-risk prostate cancer patients. Our cohort included 39 T1c tumors, 78 T2 tumors and 2 T3 tumors. The Gleason score was 6 in 32 tumors, 7 in 82 tumors and 8-9 in 6 tumors. PSA ranged from 2.1-33 (median 8.0). Patients were treated with intensity-modulated radiotherapy (IMRT) with doses of 75.6-79.8 Gy in 1.8-2Gy fractions, or 60-66 Gy in 3 Gy fractions.. Twenty-five percent of patients also received neoadjuvant-concurrent bicalutamide (150mg po od). Biochemical failure, defined by Phoenix criteria or the initiation of salvage therapy, was observed in 35 patients after median follow-up of 5.4 years (range 0.9-8.8).nnnRESULTSnArray CGH showed variable PGA ranging from <1% to 35% (median 6.7%). PSA and the use of hormonal therapy independently influenced biochemical relapse, and formed a baseline clinical model to which PGA was added. PGA was found to be a strong predictor of biochemical relapse (p<0.0001) independent of the clinical prognostic factors (pre-treatment PSA, Gleason score and T-category). PGA was also found to be associated with unique tumour suppressor and oncogene gene loci clusters involved in genetic stability (e.g. loss of PTEN, p53, RB, NKX3.1, ATM, PARP-1 and gain of c-MYC; validated by in situ FISH).nnnCONCLUSIONSnThis is the first report to show genetic instability can independently predict for biochemical recurrence in intermediate-risk prostate cancer. Current studies are associating specific gene loci regions with clinical outcome. Our results could provide a way forward for individualized medicine for non-indolent prostate cancer based on initial daignostic biopsy material. Supported by Prostate Cancer Canada, The Terry Fox Foundation and the Canadian Cancer Society. No significant financial relationships to disclose.