Side effects or toxicities are frequent, undesirable companions of almost all forms of non-surgical cancer therapy. It is unusual for patients to complete treatment with radiation or chemotherapy without experiencing at least one form of therapy-associated tissue injury or systemic side effect. Often, toxicities do not occur as solitary events; rather, they result in clusters of symptoms that share a common biological aetiology. Like any disease, cancer treatment-related toxicities (CTRTs) vary in their severity. But, in contrast to most diseases in which incidence is described as being present or absent, the current approach to CTRT typically limits reporting to severe cases only. Not only does this dilute the frequency with which CTRTs occur, but it also undermines our ability to determine the full burden of their impact and to accurately assess the cost effectiveness of potential toxicity interventions. In this article, we report the results of a directed literature review for the years 2000-2012, in which we studied and compared three tissue-based toxicities (nausea and vomiting, diarrhoea, and oral mucositis) and one systemic toxicity (fatigue). Our results confirm the heavy burden of resource use and cost associated with CTRTs. The inclusion of fatigue in our analysis provided an opportunity to compare and contrast a toxicity in which there are both acute and chronic consequences. Our findings also demonstrate a number of challenges to, and opportunities for, future study. Among the most obvious are the lack of provider consistency in diagnosis and grading, especially when there is no global agreement on severity scales. Compounding this inconsistency is the disconnect between healthcare providers and patients that exists when describing toxicity severity and impact. In many cases, cancer can be thought of as a chronic disease that requires prolonged but episodic treatment once the acute disease is eradicated. This change reflects increasing treatment successes, but it also implies that the burden of CTRTs will be expanded and prolonged. Creation of hierarchical attribution of costs in the presence of simultaneous CTRTs, accurate coding, and consistent tracking tools for toxicities will be imperative for effective appraisal of the costs associated with cancer treatment regimen toxicities.