Objective  To analyze the natural history of patients with peritoneal carcinomatosis and to explore independent prognostic factors associated with it.

  Methods  From August 2015 to April 2022, independent prognostic factors were screened from the complete survival data of 135 patients of Beijing Shijitan Hospital, Capital Medical University with peritoneal carcinomatosis using univariate and multivariate analyses.

  Results  The median overall survival in the 135 patients with peritoneal carcinomatosis was 12.2 months (95% confidence interval CI:10.6–13.8). Univariate survival analysis determined 10 factors as prognostically significant: patient age (P=0.002), the Karnofsky performance status (KPS) (P<0.001), malnutrition (P<0.001), TNM stage (P<0.001), primary tumor site (P<0.001), surgery (P<0.001), chemotherapy (P<0.001), radiotherapy (P=0.028), traditional Chinese medicine (P=0.007), and cerebral infarction (P<0.001). Multivariate survival analysis identified five independent prognostic factors: the KPS (hazard ratio HR=4.986, 95%CI: 2.540–9.787, P<0.001), malnutrition (HR=3.164, 95%CI: 1.704–5.877, P=0.001), TNM stage (HR=2.632, 95%CI: 1.344–5.157, P=0.017), surgery (HR=2.110, 95%CI: 1.170–3.804, P=0.013), and traditional Chinese medicine (HR=1.882, 95%CI: 1.043–3.396, P=0.036).

  Conclusions  The prognosis of patients with peritoneal carcinomatosis is poor. Enhancing the performance status of patients and incorporating traditional Chinese medicine into a holistic treatment plan may be key factors in improving clinical outcomes.