Grey areas and evidence gaps in the management of rectal cancer as revealed by comparing recommendations from clinical guidelines Publication date: January 2020 Source: Cancer Treatment Reviews, Volume 82 Author(s): G. Bregni, T. Akin Telli, S. Camera, C. Baratelli, L. Shaza, A. Deleporte, L. Moretti, M.A. Bali, G. Liberale, A. Hendlisz, F. Sclafani Abstract Background While the management of nonmetastatic and oligometastatic rectal cancer has rapidly evolved over the last few decades, many grey areas and highly debated topics remain that foster significant variation in clinical practice. We aimed to identify controversial points and evidence gaps in this disease setting by systematically comparing recommendations from national and international clinical guidelines. Methods Twenty-six clinical questions reflecting practical challenges in the routine management of nonmetastatic and oligometastatic rectal cancer patients were selected. Recommendations from the ESMO, NCCN, JSCCR, Australian and Ontario guidelines were extrapolated and compared using a 4-tier classification system (i.e., identical/very similar, similar, slightly different, different). Overall agreement between guidelines (i.e., substantial/complete disagreement, partial disagreement, partial agreement, substantial/complete agreement) was assessed for each clinical question and compared against the highest level of available evidence by using the χ2 statistic test. Results Guidelines were in substantial/complete agreement, partial agreement, partial disagreement, and substantial/complete disagreement for 8 (30.8%), 2 (7.7%), 7 (26.9%), and 9 (34.6%) clinical questions, respectively. High level of evidence supported clinical recommendations in 3/10 cases (30%) where guidelines were in agreement and in 10/16 cases (62.5%) where guidelines were in disagreement (χ2 = 2.6, p = 0.106). Agreement was frequently reached for questions regarding diagnosis, staging, and radiology/pathology pro-forma reporting, while disagreement characterised most of the treatment-related topics. Conclusions Substantial variation exists across clinical guidelines in the recommendations for the management of nonmetastatic and oligometastatic rectal cancer. This variation is only partly explained by the lack of supporting, high-level evidence.

Primary and acquired resistance mechanisms to immune checkpoint inhibition in Hodgkin lymphoma Publication date: January 2020 Source: Cancer Treatment Reviews, Volume 82 Author(s): Johanna Veldman, Lydia Visser, Anke van den Berg, Arjan Diepstra Abstract Hodgkin lymphoma is a B cell derived malignancy characterized by a low number of tumor cells within an environment consisting of inflammatory cells. Recently, immune checkpoint blockade targeting the PD-1-PD-L1 axis has shown to be a great success in relapsed and refractory Hodgkin lymphoma patients. However, complete responses are scarce and median progression-free survival is limited to around 11–15 months. Efficiency of PD-1 blockade in HL might be dependent on CD4+ T cells, but also tumor associated macrophages (TAMs) and NK cells are implicated. The aim of this review is to highlight currently known prominent immune evasion strategies and discuss their possible contribution to primary or acquired resistance to immune checkpoint blockade in Hodgkin lymphoma. These include T cell dependent mechanisms such as shaping of the inflammatory infiltrate, lack of presentation of antigens and neoantigens and production of molecules involved in suppression of T cell functionality such as other immune checkpoints, indoleamine 2,3-dioxygenase and adenosine. Moreover, the role of NK cells and TAMs in efficient PD-1 blockade will be discussed. Targeting these mechanisms in parallel to PD-1 may potentially increase efficiency of PD-1 blockade therapy.

Multiple myeloma: Role of autologous transplantation Publication date: January 2020 Source: Cancer Treatment Reviews, Volume 82 Author(s): Ioannis Ntanasis-Stathopoulos, Maria Gavriatopoulou, Efstathios Kastritis, Evangelos Terpos, Meletios A. Dimopoulos Abstract Autologous stem cell transplantation (ASCT) has been the mainstay of multiple myeloma (MM) treatment for approximately 30 years. Although the continuous introduction of novel agents in the armamentarium against MM has questioned its value, ASCT remains a backbone treatment for fit MM patients. However, there is no unanimous approach for several aspects including the positioning of ASCT in the therapeutic algorithm either upfront or following the first relapse, the need for single or tandem ASCT, as well as the role of ASCT as salvage therapy. Furthermore, the anti-CD38 monoclonal antibodies along with the next generation proteasome inhibitors and immunomodulatory drugs provide a platform for optimizing the induction and consolidation/maintenance regimens. In this review, we present current data pertaining to all aspects of ASCT in MM, whereas we highlight the open issues that should be addressed in the design of future clinical trials in the field.

Androgen receptor plasticity and its implications for prostate cancer therapy Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Oliver Snow, Nada Lallous, Kriti Singh, Nathan Lack, Paul Rennie, Artem Cherkasov Abstract Acquired resistance to a drug treatment is a common problem across many cancers including prostate cancer (PCa) - one of the major factors for male mortality. The androgen receptor (AR) continues to be the main therapeutic PCa target and despite the success of modern targeted therapies such as enzalutamide, resistance to these drugs eventually develops. The AR has found many ways to adapt to treatments including overexpression and production of functional, constitutively active splice variants. However, of particular importance are point mutations in the ligand binding domain of the protein that convert anti-androgens into potent AR agonists. This mechanism appears to be especially prevalent with the AR in spite of some distant similarities to other hormone nuclear receptors. Despite the AR being one of the most studied and attended targets in cancer, those gain-of-function mutations in the receptor remain a significant challenge for the development of PCa therapies. This drives the need to fully characterize such mutations and to consistently screen PCa patients for their occurrence to prevent adverse reactions to anti-androgen drugs. Novel treatments should also be developed to overcome this resistance mechanism and more attention should be given to the possibility of similar occurrences in other cancers.

Molecular insight of regorafenib treatment for colorectal cancer Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Hiroyuki Arai, Francesca Battaglin, Jingyuan Wang, Jae Ho Lo, Shivani Soni, Wu Zhang, Heinz-Josef Lenz Abstract Regorafenib is a multi-targeting kinase inhibitor approved for the treatment of metastatic colorectal cancer patients in refractory to standard chemotherapy. Similarly to sorafenib, this agent was originally developed as a RAF1 inhibitor. However, the kinase inhibitory profile is distinct from sorafenib. A broad-spectrum of kinase inhibition induces wide-range drug sensitivity, irrespective of mutation status of major oncogenes. This agent’s main therapeutic effects are anti-angiogenesis and the remodeling of tumor microenvironment through several mechanisms of action. The dual blockade of VEGF receptors and TIE2 can lead to both additive anti-angiogenesis effects and the suggestive unique regulation of vessel stability. Additionally, it inhibits molecular escape pathways to VEGF inhibition (e.g., FGF, PIGF, and PDGF signaling), enabling its continuous antiangiogenic effect even in tumors resistant to VEGF inhibitors. Furthermore, regorafenib has the important effect of enhancing anti-tumor immunity via macrophage modulation. Based on this concept, clinical trials have been recently launched for the development of a combination strategy with immune checkpoint inhibitors. Contrary to regorafenib induced clinical benefits and advances in the novel strategy, currently no predictive biomarkers have been identified. In the present review, we revisit and summarize regorafenib’s unique mechanisms of action. The review could highlight molecular insights and provide some perspective for the search of predictive biomarkers used in metastatic colorectal cancer patients treated with regorafenib.

New therapeutic targets in pancreatic cancer Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Eleonora Lai, Marco Puzzoni, Pina Ziranu, Andrea Pretta, Valentino Impera, Stefano Mariani, Nicole Liscia, Paolo Soro, Francesca Musio, Mara Persano, Clelia Donisi, Simona Tolu, Francesca Balconi, Annagrazia Pireddu, Laura Demurtas, Valeria Pusceddu, Silvia Camera, Francesco Sclafani, Mario Scartozzi Abstract Pancreatic ductal adenocarcinoma (PDAC) is associated with poor survival. Of all newly diagnosed patients, only about 20% can benefit from a potentially curative surgical resection, the remaining 80% presenting with unresectable locally advanced (LAPC) or metastatic (MPC) disease. Currently, there are limited therapeutic options for LAPC and MPC patients. Furthermore, despite intensive research efforts to better understand the molecular bases of PDAC and the biological relevance of its tumor microenvironment, treatments still largely consist of classical cytotoxic chemotherapy agents. Several studies of genetic and epigenetic sequencing have demonstrated the existence of 4 molecular PDAC subtypes, with heterogeneous genetic characteristics and different biological behaviour: squamous, pancreatic progenitor, immunogenic and aberrantly differentiated endocrine exocrine (ADEX). These distinct subtypes derive from alterations at multiple levels. Apart from the DNA repair pathway, however, none of these has so far been validated as a clinically relevant therapeutic target. Also, PDAC is unique from an immunological perspective and many studies have recently tried to elucidate the role of intratumoral effector T-cells, RAS oncogene, immunosuppressive leukocytes and desmoplastic reaction in maintaining the immunological homeostasis of this disease. However, there still remains much to be learned about the mechanisms whereby the pancreatic immune microenvironment promotes immune escape of cancer cells. Furthermore, while therapies targeting the stroma as well as immunotherapies hold promise for the future, these are not yet standard of care. This review aims to outline the state-of-the-art of LAPC and MPC treatment, highlighting data on the target therapies failure and current ongoing clinical trials on new promising therapeutic strategies.

RET fusions in solid tumors Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Andrew Y. Li, Michael G. McCusker, Alessandro Russo, Katherine A. Scilla, Allison Gittens, Katherine Arensmeyer, Ranee Mehra, Vincenzo Adamo, Christian Rolfo Abstract The RET proto-oncogene has been well-studied. RET is involved in many different physiological and developmental functions. When altered, RET mutations influence disease in a variety of organ systems from Hirschsprung’s disease and multiple endocrine neoplasia 2 (MEN2) to papillary thyroid carcinoma (PTC) and non-small cell lung cancer (NSCLC). Changes in RET expression have been discovered in 30–70% of invasive breast cancers and 50–60% of pancreatic ductal adenocarcinomas in addition to colorectal adenocarcinoma, melanoma, small cell lung cancer, neuroblastoma, and small intestine neuroendocrine tumors. RET mutations have been associated with tumor proliferation, invasion, and migration. RET fusions or rearrangements are somatic juxtapositions of 5′ sequences from other genes with 3′ RET sequences encoding tyrosine kinase. RET rearrangements occur in approximately 2.5–73% of sporadic PTC and 1–3% of NSCLC patients. The most common RET fusions are CDCC6-RET and NCOA4-RET in PTC and KIF5B-RET in NSCLC. Tyrosine kinase inhibitors are drugs that target kinases such as RET in RET-driven (RET-mutation or RET-fusion-positive) disease. Multikinase inhibitors (MKI) target various kinases and other receptors. Several MKIs are FDA-approved for cancer therapy (sunitinib, sorafenib, vandetanib, cabozantinib, regorafenib, ponatinib, lenvatinib, alectinib) and non-oncologic disease (nintedanib). Selective RET inhibitor drugs LOXO-292 (selpercatinib) and BLU-667 (pralsetinib) are also undergoing phase I/II and I clinical trials, respectively, with preliminary results demonstrating partial response and low incidence of serious adverse events. RET fusions provide a viable therapeutic target for oncologic treatment, and further study is warranted into the prevalence and pathogenesis of RET fusions as well as development of current and new tyrosine kinase inhibitors.

Trametinib in the treatment of multiple malignancies harboring MEK1 mutations Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Tong Lian, Changying Li, Haitao Wang Abstract The aberrant activation of RAS-derived mitogen-activated protein kinase (MAPK) signaling pathway plays a prominent role in tumorigenesis of an array of malignancies. The reasons are usually the upstream activated mutations including mitogen-activated protein kinase kinase 1/2 (MEK1/2). As oncogenic mutations, MEK1 mutations have been observed in a variety of malignancies including melanoma, histiocytic neoplasms, colorectal cancer and lung cancer. Presently, the use of trametinib, a highly selective MEK1/2 inhibitor, was limited to BRAF mutations, according to the approvals of FDA. Therefore, we consider that this is a question worth studying that whether malignancies with MEK1 mutations are sensitive to the treatment of trametinib. This review discussed the function of MEK1 mutations, retrieved the frequency and distribution of MEK1 mutations in various malignancies, and reviewed the basic experiments and clinical case reports on trametinib in the treatment of cell lines or patients with MEK1 mutations. Most studies have demonstrated that trametinib was effective to cells or tumor patients harboring MEK1 mutations, which suggest that the MEK1 mutations might be potential indications of trametinib therapy. In addition, it was also reported that resistance was observed in the treatment of trametinib, suggesting that different MEK1 mutations may have different response to trametinib, and further studies are necessary to distinguish that which MEK1 mutations are appropriate for the treatment with trametinib and which are not.

Should we favour the use of 5 × 5 preoperative radiation in rectal cancer Publication date: December 2019 Source: Cancer Treatment Reviews, Volume 81 Author(s): Clare Kane, Rob Glynne-Jones Abstract The management of patients with “locally advanced rectal cancer” (LARC) is evolving from the original aim of reducing local recurrence. Current practice recognises the importance of surgical technique, high-quality preoperative imaging, and integration of neoadjuvant systemic chemotherapy. Contemporary protocols focus on improving survival and avoiding radical surgery with organ preservation strategies. Both short course preoperative radiotherapy (SCPRT) with immediate surgery and long-course chemoradiation (LCCRT) are standard neoadjuvant strategies, both demonstrating similar efficacy in preventing local recurrence, distant metastases and improving disease-free survival (DFS). SCPRT is highly cost-effective with high compliance rates, hence is gaining traction in Europe and East Asia, partly because of inherent flexibility in timing and the ability to add neoadjuvant systemic chemotherapy as there is a delay to surgery. SCPRT is currently not being exploited to its full extent – particularly in the USA where uptake is approximately 1% of neoadjuvant treatments for rectal cancer. We analyse the use of induction, concurrent and consolidation chemotherapy with SCPRT in a total neoadjuvant therapy (TNT) approach.

Chimeric antigen receptor T (CAR-T) cell immunotherapy for sarcomas: from mechanisms to potential clinical applications Publication date: Available online 25 November 2019 Source: Cancer Treatment Reviews Author(s): Pichaya Thanindratarn, Dylan C. Dean, Scott D. Nelson, Francis J. Hornicek, Zhenfeng Duan Abstract Survival rates for sarcoma patients have plateaued in the past few decades and remain especially grim for those with recurrent or metastatic disease. This has prompted investigation into novel immunotherapies for sarcomas, especially after their recent and well-recognized successes in other cancers. One such modality, the Chimeric Antigen Receptor (CAR) T Cell therapy, has shown promising results in treating B-cell lymphoma and acute lymphoblastic leukemia. This novel therapy functions by fusing a specific antibody derived single-chain variable fragment (scFv) with a T-cell which recognizes a specific tumor-associated antigen (TAA). Several sarcoma-associated antigens (SAA) amenable to CAR-T cell treatment have recently emerged with encouraging results. These include human epidermal growth factor receptor 2 (HER2), disialoganglioside (GD2), interleukin 11 Receptor Subunit Alpha (IL-11RA), fibroblast activation protein (FAP), B7-H3, CD44v6, insulin-like growth factor 1 receptor (IGF-1R), and tyrosine kinase orphan-like receptor 1 (ROR1). Given the limitations of current medical therapies, novel treatment strategies are urgently needed. As a sarcoma treatment modality, CAR-T cell therapy is highly promising and continues to draw interest especially as new clinical trials emerge. Here we review recent breakthrough CAR-T cell studies in sarcoma, the targets which define them, and approaches to minimizing host cytotoxicity.