Objectives: This study aimed to identify acupoint selection patterns for breast cancer-related pain using the Knowledge Discovery in Databases (KDD) method, construct a data-informed candidate acupoint prescription, and preliminarily evaluate its clinical efficacy when combined with the World Health Organization three-step analgesic ladder. Methods: Databases including China National Knowledge Infrastructure, VIP Information, WanFang, PubMed, and Web of Science were searched from inception to May 2024. An Excel-based dataset was developed to analyze acupoint frequency and meridian attribution. Acupuncture prescriptions for cancer pain without specifying cancer type were retained as potentially informative references for breast cancer-related pain. Sixty eligible patients were randomized into two groups. The control group received standard three-step analgesics, including celecoxib, tramadol sustained-release, or oxycodone sustained-release according to pain severity. The intervention group received the same regimen plus a KDD-derived acupuncture prescription consisting of bilateral Hegu (LI4), Zusanli (ST36), Neiguan (PC6), Taichong (LR3), Sanyinjiao (SP6), and Ashi points. Needles were retained for 30 minutes using balanced stimulation, five sessions per week for three weeks. Outcomes included pain intensity, breakthrough pain frequency, duration of pain relief, Karnofsky Performance Status, sleep quality, depressive symptoms, analgesic efficacy, quality of life, and safety. Results: The KDD-derived candidate prescription was associated with a higher overall response rate than analgesics alone. Patients receiving adjunctive acupuncture showed greater reductions in pain intensity and breakthrough pain episodes, as well as improvements in functional status, sleep quality, and depressive symptoms. Fewer adverse events were reported in the acupuncture group. Conclusions: This study proposes a potential acupoint combination for relieving breast cancer-related pain based on distal meridian points and local tender points. Combined acupuncture and conventional pharmacotherapy may improve analgesic outcomes, quality of life, and psychological status, with a favorable safety profile.