OBJECTIVES: Although recent therapeutic advances in aBC have been made, little is known about patient and caregiver perceptions of different systemic anticancer treatments. To further explore this, we conducted an SML study to assess patient and caregiver perceptions of chemotherapy and immunotherapy (IO) for aBC using social media–posted data.

METHODS: This retrospective, real-world study evaluated written public posts on geolocated social media in Eu5 (France, Germany, Spain, Italy, and the UK) posted from October 2017 to October 2022. Natural language processing methods were used to filter out irrelevant content and identify posts from patients and caregivers. Posts mentioning any line of chemotherapy or IO were qualitatively analyzed by 2 researchers to classify treatment perceptions (positive, negative, mixed, or without perception).

RESULTS: 1,670 posts from 1,396 users discussing aBC in 98 public online sources were identified (699 posts from 546 patients, 971 posts from 850 caregivers). Half of patients were male (272 [49.8%]) and most caregivers were female (474 [55.8%]); average age was 52.8 and 35.2 years, respectively. Among posts mentioning chemotherapy (n=553), 58.6% did not express any opinion; in posts that did, negative perceptions (23.2%) were more commonly reported than positive (9.2%). Perceived chemotherapy benefits, as identified in 69 posts, were effectiveness (35.4%), tumor reduction (14.5%), and treatment tolerance (13.0%). In posts mentioning IO and expressing an opinion (n=52/115), 21.7% expressed a positive perception and 9.6% negative. Among those mentioning perceived benefits of IO (n=20/52), 50% cited its effectiveness.

CONCLUSIONS: This qualitative study provides valuable insights on how to improve aBC treatment experience among patients and caregivers. Strengthening support for patients receiving chemotherapy may help them and their caregivers manage side effects and improve their perceptions. This could enable more patients to achieve disease control and become eligible to receive avelumab first-line maintenance treatment to obtain survival benefits.