Original Article

Analysis of V5 Predicting Radiation Pneumonitis in Patients Received Thoracic Irradiation Treatment

Bu-Hai Wang, Xiao-Lei Wang, Jian-Qi Yang and Wei Hua
World Journal of Surgical Medical and Radiation Oncology 2014, 3:4

Abstract

Background

To examine V5 as the dosimetric predictor of radiation pneumonitis in patients received thoracic radiation therapy beside V20, V30 and MLD.

Methods

One-hundred patients receiving thoracic irradiation from 2011 to 2012 at Subei People’s Hospital were retrospectively reviewed, from which esophageal and lung cancer patients were eighty-six and fourteen, respectively. Pneumonitis was graded by using the Common Terminology Criteria for Adverse Events version 4.0. Dosimetric parameters (V5, V10, V15, V20, V25, and V30) were entered as continuous variables. A cross tabulation, an independent t-test and a receiver observer curve (ROC) were used to analyze the data.

Results

In the final, 50(50%) of total 100 patients had grade 0-1 RP, 44(44%) had grade 2 RP, 4(4%) had grade 3 RP and 2(2%) had grade 4 RP. No significant discrepancy was found between grade 0-1 and grade 2-4 in the following clinical parameters, such as age, gender, ECOG performance status and history of chemotherapy. No significant difference of RP incidence was found between Non-CT and Concurrent-CT arms (χ2 = 0.026, P > 0.1). The ROC indicated the AUC value was 0.627 for V5 (P = 0.034).

Conclusions

Those patients whose DVH parameters such as MLD, V20 and V30 were constrainted still occur RP. V5 was a statistically significant parameter associated with grade 2-4. We recommend V5 should be kept as low as possible, in addition to the conventional dosimetric factors. 50% of V5 is considered to be a threshold, the incidence of grade≥2 RP in the group with V5< 50% and ≥ 50% were 59.36% and 33.3 %( P < 0.05).

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