Soft tissue sarcomas (STS) are rare solid tumors of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Guidelines for STS provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as intra-abdominal/retroperitoneal STS, gastrointestinal stromal tumors, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis, staging, and treatment of STS of the extremities, superficial trunk, or head and neck; outlines treatment recommendations by disease stage; and reviews the evidence to support the guidelines recommendations.

Natural killer (NK) cells play a major role in cancer immunotherapies that involve tumor-antigen targeting by monoclonal antibodies (mAbs). NK cells express a variety of activating and inhibitory receptors that serve to regulate the function and activity of the cells. In the context of targeting cells, NK cells can be “specifically activated” through certain Fc receptors that are expressed on their cell surface. NK cells can express FcγRIIIA and/or FcγRIIC, which can bind to the Fc portion of immunoglobulins, transmitting activating signals within NK cells. Once activated through Fc receptors by antibodies bound to target cells, NK cells are able to lyse target cells without priming, and secrete cytokines like interferon gamma to recruit adaptive immune cells. This antibody-dependent cell-mediated cytotoxicity (ADCC) of tumor cells is utilized in the treatment of various cancers overexpressing unique antigens, such as neuroblastoma, breast cancer, B cell lymphoma, and others. NK cells also express a family of receptors called killer immunoglobulin-like receptors (KIRs), which regulate the function and response of NK cells toward target cells through their interaction with their cognate ligands that are expressed on tumor cells. Genetic polymorphisms in KIR and KIR-ligands, as well as FcγRs may influence NK cell responsiveness in conjunction with mAb immunotherapies. This review focuses on current therapeutic mAbs, different strategies to augment the anti-tumor efficacy of ADCC, and genotypic factors that may influence patient responses to antibody-dependent immunotherapies.

Interest in combining radiotherapy and immune checkpoint therapy is growing rapidly. In this study, we explored a novel combination of this type to augment anti-tumor immune responses in preclinical murine models of melanoma, neuroblastoma, and head and neck squamous cell carcinoma. Cooperative effects were observed with local radiotherapy and intratumoral injection of tumor-specific antibodies, arising in part from enhanced antibody-dependent cell-mediated cytotoxicity (ADCC). We could improve this response by combining radiation with intratumoral injection of an IL-2-linked tumor-specific antibody (termed here an immunocytokine), resulting in complete regression of established tumors in most animals associated with a tumor-specific memory T cell response. Given the T cell response elicited by combined local radiation and intratumoral immunocytokine, we tested the potential benefit of adding this treatment to immune checkpoint blockade. In mice bearing large primary tumors or disseminated metastases, the triple-combination of intratumoral immunocytokine, radiation, and systemic anti-CTLA-4 improved primary tumor response and animal survival compared to combinations of any two of these three interventions. Taken together, our results show how combining radiation and intratumoral immunocytokine in murine tumor models can eradicate large tumors and metastases, eliciting an in situ vaccination effect that can be leveraged further by T cell checkpoint blockade, with immediate implications for clinical evaluation.

Neoantigens induced by random mutations and specific to an individual's cancer are the most important tumor antigens recognized by T cells. Among immunologically “cold” tumors, limited recognition of tumor neoantigens results in the absence of a de novo antitumor immune response. These “cold” tumors present a clinical challenge as they are poorly responsive to most immunotherapies, including immune checkpoint inhibitors (ICIs). Radiation therapy (RT) can enhance immune recognition of “cold” tumors, resulting in a more diversified antitumor T‐cell response, yet RT alone rarely results in a systemic antitumor immune response. Therefore, a multifunctional bacterial membrane‐coated nanoparticle (BNP) composed of an immune activating PC7A/CpG polyplex core coated with bacterial membrane and imide groups to enhance antigen retrieval is developed. This BNP can capture cancer neoantigens following RT, enhance their uptake in dendritic cells (DCs), and facilitate their cross presentation to stimulate an antitumor T‐cell response. In mice bearing syngeneic melanoma or neuroblastoma, treatment with BNP+RT results in activation of DCs and effector T cells, marked tumor regression, and tumor‐specific antitumor immune memory. This BNP facilitates in situ immune recognition of a radiated tumor, enabling a novel personalized approach to cancer immunotherapy using off‐the‐shelf therapeutics.

Molecular and cellular effects of radiotherapy on tumor microenvironment (TME) can help prime and propagate antitumor immunity. We hypothesized that delivering radiation to all tumor sites could augment response to immunotherapies. We tested an approach to enhance response to immune checkpoint inhibitors (ICIs) by using targeted radionuclide therapy (TRT) to deliver radiation semiselectively to tumors. NM600, an alkylphosphocholine analog that preferentially accumulates in most tumor types, chelates a radioisotope and semiselectively delivers it to the TME for therapeutic or diagnostic applications. Using serial 86Y-NM600 positron emission tomography (PET) imaging, we estimated the dosimetry of 90Y-NM600 in immunologically cold syngeneic murine models that do not respond to ICIs alone. We observed strong therapeutic efficacy and reported optimal dose (2.5 to 5 gray) and sequence for 90Y-NM600 in combination with ICIs. After combined treatment, 45 to 66% of mice exhibited complete response and tumor-specific T cell memory, compared to 0% with 90Y-NM600 or ICI alone. This required expression of STING in tumor cells. Combined TRT and ICI activated production of proinflammatory cytokines in the TME, promoted tumor infiltration by and clonal expansion of CD8+ T cells, and reduced metastases. In mice bearing multiple tumors, combining TRT with moderate-dose (12 gray) external beam radiotherapy (EBRT) targeting a single tumor augmented response to ICIs compared to combination of ICIs with either TRT or EBRT alone. The safety of TRT was confirmed in a companion canine study. Low-dose TRT represents a translatable approach to promote response to ICIs for many tumor types, regardless of location.