Palliative surgery is commonly performed in cancer centers worldwide. Yet, there is little agreement on the definition of palliative surgery or its relevant outcomes. This systematic review sought to characterize the definitions of palliative surgery and outcomes for patients with cancer undergoing thoraco-abdominal procedures. Following PRISMA guidelines, we conducted a search using PubMed, EMBASE and CINAHL databases to identify English-language publications between August 1, 2005, and December 31, 2023 reporting palliative thoraco-abdominal procedures for patients with cancer. Definitions of palliative surgery were coded and analyzed using an inductive approach. Outcomes were classified according to an outcome measures hierarchy. Among 92 articles met inclusion criteria and four themes emerged in how palliative surgery was defined throughout the literature: prognosis (incurable cancer diagnosis), purpose (intent to treat symptoms or improve quality of life), procedure type (specific operative interventions), or persistent disease following surgery (incomplete cytoreduction). Survival (90%) and perioperative complications/morbidity (72%) were the most commonly reported outcomes, whereas symptom relief, quality of life, and sustainability of success were infrequently reported. Definitions of palliative surgery vary across studies of patients with cancer undergoing thoracic or abdominal procedures and measured outcomes often do not align with the intent of surgery.