Establishment of a prediction model for severe acute radiation enteritis associated with cervical cancer radiotherapy

Abstract

Background: Cervical cancer is one of the most common gynecological malignant tumors. Radiation enteritis (RE) leads to radiotherapy intolerance or termination of radiotherapy, which negatively impacts the therapeutic effect and seriously affects the quality of life of patients. If the incidence of RE in patients can be predicted in advance, and targeted clinical preventive treatment can be carried out, the side effects of radiotherapy in cervical cancer patients can be significantly reduced. Furthermore, accurate prediction of RE is essential for the selection of individualized radiation dose and the optimization of the radiotherapy plan.

Aim: To analyze the relationships between severe acute RE (SARE) of cervical cancer radiotherapy and clinical factors and dose-volume parameters retrospectively.

Methods: We included 50 cervical cancer patients who received volumetric modulated arc therapy (VMAT) from September 2017 to June 2018 in the Department of Radiotherapy at The First Affiliated Hospital Soochow University. Clinical and dose-volume histogram factors of patients were collected. Logistic regression analysis was used to evaluate the predictive value of each factor for SARE. A nomogram to predict SARE was developed (SARE scoring system ≥ 3 points) based on the multiple regression coefficients; validity was verified by an internal verification method.

Results: Gastrointestinal and hematological toxicity of cervical cancer VMAT gradually increased with radiotherapy and reached the peak at the end of radiotherapy. The main adverse reactions were diarrhea, abdominal pain, colitis, anal swelling, and blood in the stool. There was no significant difference in the incidence of gastrointestinal toxicity between the radical and postoperative adjuvant radiotherapy groups (P > 0.05). There were significant differences in the small intestine V₂₀, V₃₀, V₄₀, and rectal V₄₀ between adjuvant radiotherapy and radical radiotherapy after surgery (P < 0.05). Univariate and multivariate analyses revealed anal bulge rating (OR: 14.779, 95%CI: 1.281-170.547, P = 0.031) and disease activity index (DAI) score (OR: 53.928, 95%CI: 3.822-760.948, P = 0.003) as independent predictors of SARE.

Conclusion: Anal bulge rating (> 0.500 grade) and DAI score (> 2.165 points) can predict SARE. The nomogram shows potential value in clinical practice.

Keywords: Cervical cancer; Intensity-modulated radiotherapy; Nomogram; Predictor; Radiation enteritis.

Figure 1

Disease activity index score during volumetric modulated arc therapy in 50 patients with cervical cancer.

Figure 2

Development and validation of the nomogram. A: Kendall’s rank correlation analyses among factors with P < 0.05 in univariate logistic regression; B: Nomogram predicting the occurrence of severe acute radiation enteritis (SARE). For each individual patient, two lines are drawn upward to determine the points received from the two variables in the nomogram; the sum of these points is located on the “Total Points” line, and a line is drawn downward to determine the likelihood of this patient to have SARE; C: Receiver operating characteristic curves of anal bulge rating. Disease activity index score vs the predictive model; D: Calibration curves of the nomogram predicting the occurrence of SARE. The x-axis and y-axis indicate the predicted and actual probabilities of having SARE, respectively; E: Decision curves of the nomogram predicting the occurrence of SARE. The x-axis shows the threshold probabilities. The y-axis measures the net benefit, which was calculated by adding the true positives and subtracting the false positives. NOMO: Nodal modulator; AUC: Area under the receiver operating characteristic curve; DAI: Disease activity index.