Immunotherapy in Sarcoma: Current Data and Promising Strategies.

Traditionally sarcomas have been considered immunologically quiet tumours, with low tumour mutational burden (TMB) and an immunosuppressive tumour microenvironment (TME), consisting of decreased T-cell infiltration and elevated levels of H1F1α, macrophages and neutrophils.1,2 However, research has shown that a subset of sarcomas are immunologically 'hot' with either high TMB, PDL-1 expression, CD8+ T cells or presence of tertiary lymphoid structures (TLS) demonstrating sensitivity to immunotherapy.3,4 Here, we review the current evidence for immunotherapy use in bone sarcomas (BS) and soft tissue sarcomas (STS), with immune checkpoint inhibitors (ICI) and adoptive cellular therapies including engineered T-cell therapies, chimeric antigen receptor (CAR) T-cell therapies, tumour infiltrating lymphocytes (TILs) and cancer vaccines and biomarkers of response.

Seminoma and dysgerminoma: evidence for alignment of clinical trials and de-escalation of systemic chemotherapy.

Malignant germ cell tumours are a group of rare cancers whose incidence peaks in late adolescence and early adulthood. Dysgerminomas of the ovary and seminomas of the testis are analogous diseases, but seminomas have a 10-fold higher incidence. The two tumours are morphologically identical and are only differentiated by surrounding organ-specific tissue or testicular germ cell neoplasia in situ. They share genetic features including KIT and RAS mutations, amplification of chromosome 12p, and expression of pluripotency markers (NANOG (Nanog homeobox), OCT3/4 (Octamer-binding transcription factor 3/4), and SAL4 (Spalt-like trascription factor 4)). Both histologies are exquisitely sensitive to platinum chemotherapy, and the combination of bleomycin, etoposide, and cisplatin (BEP) yields survival rates greater than 90%. However, BEP causes significant, lifelong toxicity (cardiovascular, renal, respiratory, and neurological) in these young patients with an expectation of cure. Here, we comprehensively review the biological features of dysgerminoma and seminoma to demonstrate that they are biologically analogous diseases. We present available clinical trial data supporting de-escalation of chemotherapy treatment. Finally, we propose that future trials should enrol men, women, and children to benefit all patients regardless of age or sex.

Bad to the Bone: Emerging Approaches to Aggressive Bone Sarcomas.

Bone sarcomas are rare heterogeneous tumors that affect patients of all ages including children, adolescent young adults, and older adults. They include many aggressive subtypes and patient groups with poor outcomes, poor access to clinical trials, and lack of defined standard therapeutic strategies. Conventional chondrosarcoma remains a surgical disease, with no defined role for cytotoxic therapy and no approved targeted systemic therapies. Here, we discuss promising novel targets and strategies undergoing evaluation in clinical trials. Multiagent chemotherapy has greatly improved outcomes for patients with Ewing sarcoma (ES) and osteosarcoma, but management of those with high-risk or recurrent disease remains challenging and controversial. We describe the impact of international collaborative trials, such as the rEECur study, that aim to define optimal treatment strategies for those with recurrent, refractory ES, and evidence for high-dose chemotherapy with stem-cell support. We also discuss current and emerging strategies for other small round cell sarcomas, such as CIC-rearranged, BCOR-rearranged tumors, and the evaluation of emerging novel therapeutics and trial designs that may offer a new paradigm to improve survival in these aggressive tumors with notoriously bad (to the bone) outcomes.

Treatment de-escalation for stage II seminoma.

International Germ Cell Cancer Collaborative Group good-risk metastatic seminoma has cure rates of >95%. Within this risk group, patients with stage II disease exhibit the best oncological outcomes with the standard-of-care treatment strategies of radiotherapy or combination chemotherapy. However, these treatments can be associated with substantial early and late toxic effects. Therapy de-escalation aims to reduce treatment morbidity whilst preserving oncological outcomes. The evidence supporting such approaches is largely from non-randomized institutional data, and therefore this strategy is not recognized as standard of care. Current de-escalation approaches for stage II seminoma include single-agent chemotherapy, radiotherapy and surgery based on early data from clinical studies. Increased recognition of emerging data on treatment modification to reduce morbidity whilst maintaining cure rates and consideration of therapy de-escalation could improve patient survivorship outcomes.

Adjuvant and post-surgical treatment in high-grade epithelial ovarian cancer.

Cytoreductive surgery is the mainstay of treatment for high-grade epithelial ovarian cancer. Although for early stage disease outcomes following surgery alone are good, the risk of recurrence necessitates adjuvant chemotherapy for the majority of patients. Post-operative chemotherapy in advanced-stage disease, or neoadjuvant chemotherapy followed by surgery has improved progression-free survival (PFS) and overall survival (OS). However, despite the use of chemotherapy, the rate of recurrence remains high. In recent years, there has been considerable increase in knowledge regarding the biology of ovarian cancer, which has led to a journey of drug discovery, facilitating the use of novel targeted agents such as VEGF inhibitors and, more recently, PARP inhibitors in the first-line treatment of ovarian cancer. Here, we outline the current evidence-based guidance for systemic therapies in ovarian cancer and highlight the ongoing research to improve patient outcomes.

The role of MET in chemotherapy resistance.

Chemotherapy remains the mainstay of treatment in the majority of solid and haematological malignancies. Resistance to cytotoxic chemotherapy is a major clinical problem and substantial research is ongoing into potential methods of overcoming this resistance. One major target, the receptor tyrosine kinase MET, has generated increasing interest with multiple clinical trials in progress. Overexpression of MET is frequently observed in a range of different cancers and is associated with poor prognosis. Studies have shown that MET promotes resistance to targeted therapies, including those targeting EGFR, BRAF and MEK. More recently, several reports suggest that MET also contributes to cytotoxic chemotherapy resistance. Here we review the preclinical evidence of MET's role in chemotherapy resistance, the mechanisms by which this resistance is mediated and the translational relevance of MET inhibitor therapy for patients with chemotherapy resistant disease.