Objective:To investigate the influencing factors of breakthrough cancer pain (BTcP) in patients with advanced pancreatic cancer.Methods:According to the inclusion and exclusion criteria, patients with advanced pancreatic cancer who were diagnosed and followed up by outpatient service in the 909th Hospital of the Joint Logistic Support Force from January 2019 to December 2020 were prospectively selected as the study subjects. According to whether breakthrough cancer pain occurred, all patients were divided into observation group (breakthrough cancer pain) and control group (no breakthrough cancer pain). The relevant clinical data of the included patients including age, gender, presence or absence of vomit, constipation, sleep disruption, frequency of basic pain every week, with or without regular medication, heavy physical labor, with or without vascular invasion, bone metastasis, abdominal metastasis and lung metastasis, as well as whether surgery, radiotherapy or chemotherapy were collected and the data of evaluation indicators during follow-up were recorded. Digital pain score (NRS) and visual analog score (VAS) were used as pain evaluation score. Univariate and logistic regression were used to analyze the related influencing factors of breakthrough cancer pain. Receiver operating characteristic curve (ROC) was drawn, and area under curve (AUC), sensitivity and specificity were calculated to analyze the predictive value for breakthrough cancer pain.Results:A total of 173 patients were included in the study, with 49 cases in the observation group and 124 cases in the control group. Univariate analysis showed that aged ≥50 years old, constipation, sleep disruption, frequency of basic pain ≥3 times, irregular medication, heavy physical labor, bone metastasis, lung metastasis, radiochemotherapy, high NRS score and high VAS score were the influencing factors for breakthrough cancer pain (all P value <0.05). Multivariate analysis showed that irregular medication ( OR=1.879, 95% CI 2.473-4.757, P=0.002), basal pain ≥3 times ( OR=2.067, 95% CI 1.364-6.825, P=0.004), bone metastasis ( OR=2.756, 95% CI 1.153-5.846, P<0.001), NRS score ( OR=3.787, 95% CI 2.647-5.958, P<0.001), VAS score ( OR=2.684, 95% CI 1.545-7.878, P<0.001), were the risk factors for breakthrough cancer pain. The AUC of NRS score for predicting the occurrence of breakthrough cancer pain was 0.665 (95% CI0.573-0.757, P=0.001), and the cut-off value was 2.5 score with a sensitivity of 61.2% and a specificity of 77.1%. The AUC for predicting breakthrough cancer pain by VAS score was 0.608 (95% CI0.515-0.701, P=0.028), and the cut-off value was 2.5 score with a sensitivity of 67.9% and a specificity of 63.7%. The AUC of NRS+ VAS score for predicting breakthrough cancer pain was 0.692 (95% CI0.604-0.780), and the cut-off value was 4.5 score with a sensitivity of 81.6% and a specificity of 79.8%. Conclusions:Patients with advanced pancreatic cancer have a high incidence of breakthrough cancer pain, which was related to a variety of factors. NRS combined with VAS score can effectively predict the occurrence of breakthrough cancer pain.