Purpose: Breast cancer survivors represent a unique group of patients who need complex and continuous care after their cancer treatment. These patients often see several providers in various specialties. This study aimed to analyze how traditional Chinese medicine (TCM) integration within care networks of patients with breast cancer might be related to health care costs and patient outcomes under the National Health Insurance program in Taiwan. Methods: We enrolled all patients who underwent definitive mastectomy for newly diagnosed breast cancer between 2007 and 2015. We analyzed the presence of TCM physicians and the patient-sharing relationship between TCM physicians and other physicians during the first year after mastectomy. The outcomes included all-cause mortality, avoidable hospitalization, and medical expenditures. Results: There were 68,987 patients with breast cancer, with a median age of 53 years. After propensity score matching, patients whose TCM doctors had the highest connectedness with other physicians had the lowest odds of avoidable hospitalization (adjusted odds ratio 0.86; 95% confidence interval [CI], 0.78–0.96) and lowest hazard of mortality (adjusted hazard ratio, 0.82; 95% CI, 0.72–0.93), followed by those with TCM doctors with medium connectedness, then low connectedness, and lastly those patients with no TCM doctor in their care network. Conclusions: A dose-response pattern was observed regarding the relationship between TCM doctor’s connectedness with other physicians within a patient’s care network and patient outcomes. Implications for cancer survivors: The findings demonstrated that stronger connectedness between TCM and other physicians could help improve the health outcomes of breast cancer survivors.