The use of androgen deprivation therapy and second-line anti-androgens in prostate cancer has led to the emergence of tumors employing multiple androgen receptor (AR)-dependent and AR-independent mechanisms to resist AR-targeted therapies in castration-resistant prostate cancer (CRPC). While the AR signaling axis remains the cornerstone for therapeutic development in CRPC, a clearer understanding of the heterogeneous biology of CRPC tumors is needed for innovative treatment strategies. In this review, we discuss the characteristics of CRPC tumors that lack AR activity and the temporal and spatial considerations for the conversion of an AR-dependent to an AR-independent tumor type. We describe the more prevalent treatment-emergent phenotypes arising in the CRPC disease continuum, including amphicrine, AR-low, double-negative, neuroendocrine and small cell phenotypes. We discuss the association between the loss of AR activity and tumor plasticity with a focus on the roles of transcription factors like SOX2, DNA methylation, alternative splicing, and the activity of epigenetic modifiers like EZH2, BRD4, LSD1, and the nBAF complex in conversion to a neuroendocrine or small cell phenotype in CRPC. We hypothesize that only a subset of CRPC tumors have the propensity for tumor plasticity and conversion to the neuroendocrine phenotype and outline how we might target these plastic and emergent phenotypes in CRPC. In conclusion, we assess the current and future avenues for treatment and determine that the heterogeneity of CRPCs lacking AR activity will require diverse treatment approaches.
Mark P Labrecque, Joshi J Alumkal, Ilsa M Coleman, Peter S Nelson, and Colm Morrissey
Maria L Sandoval, Ammoren Dohm, and Kosj Yamoah
The current standard for the management of locally advanced and early stage metastatic prostate cancer relies on a backbone of androgen deprivation therapy (ADT) combined with radiotherapy (RT), a regimen that at a glance appears relatively straightforward. The emergence of newer diagnostic, genomic and imaging modalities have allowed for better disease risk-stratification and opened avenues for the development of more patient-centered treatment strategies. This review aims to highlight the central role of RT as part of a multi-modal approach and discuss established and emerging data for the management of locally advanced disease, biochemical recurrence, and oligometastatic disease, as well as the use of immunotherapies and radio-isotopes. This review will also briefly discuss ongoing clinical trials that provide new insights into the paradigm shift in the management of locally advanced prostate cancer.
Cristina Gurizzan, Manuel Zamparini, Marco Volante, Valeria Tovazzi, Vito Amoroso, Francesca Consoli, Fausto Petrelli, Salvatore Grisanti, Paolo Bossi, and Alfredo Berruti
Intrathyroidal thymic carcinoma (ITC) is a rare thyroid tumor that resembles thymic carcinoma, for which there are no recommendations on diagnostic and therapeutic approaches. We performed a pooled analysis of published ITC cases to describe the natural history of this disease and identify prognostic factors. We performed a systematic review of histopathological-confirmed ITC cases published in the literature in English. The following keywords were used: 'intrathyroidal thymic carcinoma', 'carcinoma showing thymus-like differentiation', 'CASTLE tumor', 'thyroid carcinoma showing thymus like differentiation'. Fifty eligible publications were identified, providing data from 132 patients, plus a case diagnosed at our institution. Median disease-free survival (DFS) of this patient series was 144 months (range 91–197), while median overall survival (OS) was not reached. Upfront surgery was performed in 97% of patients and 24% of them experienced disease recurrence after a median of 19 months (range 13–25). Complaining of major symptoms, as a sign of more advanced local stage, was the only prognostic factor significantly associated with a higher risk of death at multivariate analysis (HR 4.903, 95% CI: 1.092–22.008, P = 0.038). Postoperative radiation therapy was not associated with prognosis, while not enough data were available to assess the efficacy of chemotherapy. ITC is a rather indolent disease and ITC patients have a relatively good prognosis. Surgery is the mainstay of therapy. Survival outcome of patients depends on tumor burden and complete surgical resection. Postoperative radiation effect seems to be negligible. Data on the efficacy of chemotherapy in advanced patients are lacking.
Nely Díaz-Mejía, David García-Illescas, Rafael Morales-Barrera, Cristina Suarez, Jacques Planas, Xavier Maldonado, Joan Carles, and Joaquin Mateo
Poly (ADP-ribose) polymerase (PARP) inhibitors have antitumor activity in advanced prostate cancer associated with loss of homologous recombination repair (HRR) function. About 20% of all patients with advanced prostate cancer present germline or tumor mutations in HRR-related genes, the most common being BRCA2, mutated in approximately 10% of all advanced prostate cancers. Challenges related to sample availability, tumor heterogeneity and access to NGS technology need to be addressed for a successful implementation of genomic stratification in routine clinical practice. The recent regulatory approvals of PARP inhibitors olaparib and rucaparib represent the first molecular biomarker-guided drugs for men with prostate cancer. While these findings represent a significant advance in the field of precision medicine and prostate cancer, there are still many unsolved questions on the optimal use of PARP inhibitors in this disease. Several clinical trials have shown that different mutations in various genes are associated with distinct magnitudes of sensitivity to PARP inhibitors, with BRCA2 mutations associating with more frequent and durable responses, questioning the benefit for subset of patients with mutations in other HRR-associated genes. In this review, we scrutinize the clinical development of different PARP inhibitors for the treatment of advanced prostate cancer, and we discuss how the study of additional biomarkers and the design of rational drug combinations can maximize patient benefit from this drug class.
Sten Myrehaug, David L Chan, Victor Rodriguez-Freixinos, Hans Chung, Julie Hallet, Calvin Law, Chirag Patel, Laurent Milot, John Hudson, Hanbo Chen, and Simron Singh
Liver metastases are common in patients with neuroendocrine tumours. For patients, management must balance disease control with consideration of toxicity, given limited treatment options. Everolimus has demonstrated effectiveness in neuroendocrine neoplasms. Given emerging data of a synergistic effect with radiation therapy, we evaluated combined everolimus and radiation for neuroendocrine liver metastases. This single-arm, single-centre prospective pilot study evaluated the safety and efficacy of combined everolimus and radiotherapy for well-differentiated neuroendocrine liver metastases. Patients with unresectable liver metastases received everolimus for 30 days, followed by concurrent everolimus and liver radiotherapy, then a further 14 days of everolimus. Tolerability was evaluated using the CTCAE v.4.03. Individual metastasis response rate and local control were measured by RECIST v1.1. Overall survival, progression-free survival and freedom from a change in systemic therapy were estimated by the Kaplan–Meier method. Forty metastases were treated in 14 patients. No grade 3 or higher toxicities were identified in the concurrent treatment phase; one patient developed grade 3 toxicity in the post-radiation phase. Overall response rate was 38%. One- and 2-year local control were 97% and 71%. Median progression-free survival was 12 months. One- and 2-year overall survival were 100% and 92%. In conclusion, combined everolimus and radiation are well-tolerated for neuroendocrine liver metastases and are associated with excellent local control. The approach of selective local ablation of oligometastatic or oligoprogressive disease warrants further evaluation in this patient population.
Anela Blazevic, Martijn P A Starmans, Tessa Brabander, Roy S Dwarkasing, Renza A H van Gils, Johannes Hofland, Gaston J H Franssen, Richard A Feelders, Wiro J Niessen, Stefan Klein, and Wouter W de Herder
Metastatic mesenteric masses of small intestinal neuroendocrine tumors (SI-NETs) are known to often cause intestinal complications. The aim of this study was to identify patients at risk to develop these complications based on routinely acquired CT scans using a standardized set of clinical criteria and radiomics. Retrospectively, CT scans of SI-NET patients with a mesenteric mass were included and systematically evaluated by five clinicians. For the radiomics approach, 1128 features were extracted from segmentations of the mesenteric mass and mesentery, after which radiomics models were created using a combination of machine learning approaches. The performances were compared to a multidisciplinary tumor board (MTB). The dataset included 68 patients (32 asymptomatic, 36 symptomatic). The clinicians had AUCs between 0.62 and 0.85 and showed poor agreement. The best radiomics model had a mean AUC of 0.77. The MTB had a sensitivity of 0.64 and specificity of 0.68. We conclude that systematic clinical evaluation of SI-NETs to predict intestinal complications had a similar performance than an expert MTB, but poor inter-observer agreement. Radiomics showed a similar performance and is objective, and thus is a promising tool to correctly identify these patients. However, further validation is needed before the transition to clinical practice.
Marc Diedisheim, Solène Dermine, Anne Jouinot, Amandine Septier, Sébastien Gaujoux, Bertrand Dousset, Guillaume Cadiot, Etienne Larger, Jérôme Bertherat, Raphael Scharfmann, Benoit Terris, Romain Coriat, and Guillaume Assié
Duodenopancreatic neuroendocrine tumors (DPNETs) aggressiveness is heterogeneous. Tumor grade and extension are commonly used for prognostic determination. Yet, grade classes are empirically defined, with regular updates changing the definition of classes. Genomic screening may provide more objective classes and reflect tumor biology. The aim of this study was to provide a transcriptome classification of DPNETs. We included 66 DPNETs, covering the entire clinical spectrum of the disease in terms of secretion, grade, and stage. Three distinct molecular groups were identified, associated with distinct outcomes (log-rank P < 0.01): (i) better-outcome DPNETs with pancreatic beta-cell signature. This group was mainly composed of well-differentiated, grade 1 insulinomas; (ii) poor-outcome DPNETs with pancreatic alpha-cell and hepatic signature. This group included all neuroendocrine carcinomas and grade 3 DPNETs, but also some grade 1 and grade 2 DPNETs and (iii) intermediate-outcome DPNETs with pancreatic exocrine and progenitor signature. This group included grade 1 and grade 2 DPNETs, with some insulinomas. Fibrinogen gene FGA expression was one of the topmost expressed liver genes. FGA expression was associated with disease-free survival (HR = 1.13, P = 0.005) and could be validated on two independent cohorts. This original pathophysiologic insight provides new prognostic classification perspectives.
Wafa Bouleftour, Karima Boussoualim, Sandrine Sotton, Cecile Vassal, Thierry Thomas, Nicolas Magne, and Aline Guillot
Prostate cancer (Pca) is the most commonly diagnosed cancer affecting men in France. Before the age of 75 years old, 1 in 8 French men will have Pca. Androgen deprivation therapies (ADT) remain the standard of care. Such therapies induce significant bone loss. The bone-remodelling cycle depends on the androgen synthesis signalling pathways. Furthermore, age-specific hormonal decline plays a key role in the decrease in bone mass. As a result, the older the patients, the more likely they are to have osteoporosis if they are treated with hormone therapy. Their risk of osteoporotic fracture has an impact on their quality of life and their capacity of independent living. In recent years, newer hormone therapies (acetate abiraterone, enzalutamide, apalutamide and darolutamide) have proved efficient in metastatic castration-resistant Pca (mCRPC) patients as well as in hormone naïve patients, and actually in nonmetastatic diagnosis. The combination of these treatments with ADT highly inhibit androgen production pathways. They are prescribed to aged patients undergoing bone density loss after first-generation antiandrogen treatment. Specific recommendations for bone health management in Pca patients are currently lacking. To date, bone mineral density in patients treated with second-generation hormone therapy has never been assessed in a prospective study. This review aims at reviewing what is known about the impact of second-generation hormonotherapy on bone microenvironment.
Alastair H Davies and Amina Zoubeidi
The first case of prostate cancer was identified by histological examination by Adams, a surgeon at The London Hospital, in 1853. In his report, Adams noted that the condition was 'a very rare disease'. Now, over 150 years later, with increased life expectancy and screening, prostate cancer has become one of the most common cancers in men. In the United States alone, nearly 200,000 men are diagnosed with prostate cancer annually and about 33,000 succumb to their disease. Fifty years ago, men were typically diagnosed with prostate cancer in their seventies with disease that had metastasized to the bone and/or soft tissue. Diagnosis at such an advanced stage was a death sentence, with patients dying within 2 years. The pioneering work of Charles Huggins in the 1940s found that metastatic prostate cancer responds to androgen deprivation therapy (ADT), ushering in the rational use of hormone therapies that have irrevocably changed the course of prostate cancer disease management. Medical castration was the first effective systemic targeted therapy for any cancer and, to this day, androgen ablation remains the mainstay of prostate cancer therapy.
Himisha Beltran and Francesca Demichelis
Lineage plasticity and histologic transformation to small cell neuroendocrine prostate cancer (NEPC) is an increasingly recognized mechanism of treatment resistance in advanced prostate cancer. This is associated with aggressive clinical features and poor prognosis. Recent work has identified genomic, epigenomic, and transcriptome changes that distinguish NEPC from prostate adenocarcinoma, pointing to new mechanisms and therapeutic targets. Treatment-related NEPC arises clonally from prostate adenocarcinoma during the course of disease progression, retaining early genomic events and acquiring new molecular features that lead to tumor proliferation independent of androgen receptor activity, and ultimately demonstrating a lineage switch from a luminal prostate cancer phenotype to a small cell neuroendocrine carcinoma. Identifying the subset of prostate tumors most vulnerable to lineage plasticity and developing strategies for earlier detection and intervention for patients with NEPC may ultimately improve prognosis. Clinical trials focused on drug targeting of the lineage plasticity process and/or NEPC will require careful patient selection. Here, we review emerging targets and discuss biomarker considerations that may be informative for the design of future clinical studies.