BACKGROUND: Online discussion forums allow individuals who otherwise may be strangers to create a community where they can seek and share information. Patients with bone sarcomas and their support networks use discussion forums dedicated to cancer support. There is a paucity of published reports regarding the care experience of patients with bone sarcomas because studies on online discussion groups have primarily focused on some of the more common cancers, including breast and prostate cancer. Understanding commonly discussed themes among patients with bone sarcomas would allow treating physicians to have a better understanding of patient concerns when providing patient education and counseling. QUESTION/PURPOSE: We performed this study to review posts from bone sarcoma internet discussion boards to establish common themes related to the care experience of patients with sarcomas. METHODS: Online discussion forums were identified using the search term "sarcoma discussion forum." After identifying 12 websites, we excluded closed forum groups, websites with missing or invalid links to forums, and nonpublic forums, such as groups on Facebook. These websites include profiles and photos that are personal, and sufficient author anonymity could not be achieved for this study. Posts written between January 1, 2012, and May 1, 2022, posted on five discussion boards were reviewed and collected until we reached a point of data saturation in which we agreed that the collection of additional posts would not reveal new themes. Discussion threads were filtered to identify posts pertaining to the most common bone sarcomas: chondrosarcoma, Ewing sarcoma, and osteosarcoma. Grounded theory-the methodology of repeated analyses of qualitative data to identify recurring themes or concepts-was used to analyze posts. Caregiver posts were delineated from patient posts and categorized separately for subgroup analysis. Grounded theory, although a qualitative method, endeavors to integrate the strengths inherent in quantitative methods with qualitative approaches. Grounded theory categorizes words, language, and the meanings these imply and seeks to organize and reduce the data gathered into themes or essences, which, in turn, can be fed into descriptions, models, or theories. Our analysis used three reviews of text to assign and group codes based on repeating ideas or concepts. The first review (open coding) aims to assign codes based on the verbatim text included by the author to capture the specific thoughts and ideas of the post. The second review (axial coding) aims to consolidate the ideas of posts by applying broader concepts to each post. The third and final review (selective coding) aims to further consolidate the themes of each post by trying to embody the main message contained in a post. A total of 570 posts from 139 threads were collected and analyzed using grounded theory. Twenty-five axial codes and four selective codes were created. We defined data saturation by the absence of a new open code in the analysis of a block of 50 posts to ensure that signals of saturation were not accepted too early in the analysis. RESULTS: The four selective codes included emotional aspects or connecting with others, information support: diagnosis, information support: treatment, and information support: recovery. Of these four codes, emotional aspects and connecting with others was the most prevalent theme (78% [445 of 570] of posts) followed by information support: treatment (49% [282 of 570] of posts). Information support: diagnosis and information support: recovery were each captured in 15% of posts. CONCLUSION: Analysis of posts reveals that the two most common themes involve seeking out emotional support and information about the experiences of others with various treatment modalities. Although most of the posts we assessed contained experiential information and emotional support rather than directed medical advice, future studies should assess the accuracy of information shared among online sarcoma forums. CLINICAL RELEVANCE: Physicians caring for patients with sarcomas should not only address patient concerns related to medical care, but also provide emotional support directly and assist patients by providing resources to peer support outlets, including online discussion forums. Although we cannot ascertain the proportion of patients who use online sites given the anonymity of posts included, these findings suggest common experiential themes across patients with sarcomas outside their doctors' offices. It is important that providers be aware of reputable forums to provide as resources for their patients. The Musculoskeletal Tumor Society may further benefit from endorsing one or more of these forums and providing physician oversight to monitor misinformation.