Relationship Between V5 Volume And Acute RP In Elderly Patients With Non-operative NSCLC

Objective:To investigate the relationship between V5 volume size and acute moderate-severe radiation pneumonia in elderly patients with nonoperative non-small cell lung cancer after intensity modulated conformal radiotherapy.Methods:Using retrospective research methods,52 elderly non-surgical NSCLC patients from the Department of Thoracic Radiology of Hunan Cancer Hospital from September 2017 to September 2019 were selected.All patients received the first radical IMRT radiotherapy and successfully completed the radiotherapy plan and were followed up to 3 months after the end of radiotherapy.Their clinical data(age,gender,treatment plan,pathological type,CT images before and after treatment,etc.)and dose volume were collected The indicators in the histogram(DVH)mainly include the double lung V5,V10,V15,V20,V30 and the aVerage lung dose(MLD)index.The diagnostic criteria of RP were eValuated according to the classification criteria of the American Radiation Oncology Group(RTOG).Taking RP = 2 as the study end point,the enrolled patients were diVided into pneumonia group(RP ? 2)and control group(RP ? 1).SPSS 25.0 statistical software was used for statistical analysis,pearson chi-square test was used to analyze the composition ratio relationship of general data between the two groups of data,and single factor correlation was used to analyze the relationship between general clinical factors and moderate-to-seVere radiation pneumonitis.Logistic stepwise regression analysis was used to analyze continuous numerical Variables.P value <0.05 was considered statistically significant.The receivers operating characteristic curve(ROC)analysis was used for meaningful indicators to further find their suitable predictive critical indicators.Results:(1)In 52 patients,there were 40 patients had RP,the probability was 76.9%,21 patients had grade 1 RP,the incidence rate was 40.4%,8 patients had grade 2 RP,the incidence rate was 15.4%,11 patients had grade 3 RP,the incidence rate was 21.2%,no grade 4 and 5 RP and death cases,33 patients had ?1 RP,the incidence rate was 63.5%,19 patients had more than 2 RP,the incidence rate was 36.5%.(2)There was no statistical difference in the composition ratio of general clinical factors such as sex,age,treatment,smoking history,PS score,clinical type,pathological type,tumor stage and so on between the control group and pneumonia group(P?0.05).(3)Univariate correlation analysis revealed no significant correlation between general clinical factors such as sex,age,treatment,smoking history,PS score,clinical type,pathological type,tumor stage,and acute moderate-severe RP.(4)Among the dose parameters of DVH,V5 was predicted to be an independent influencing factor of moderate-to-severe RP in elderly nonsurgical NSCLC patients,P = 0.026.Statistical analysis of other dose volumes and average lung dose did not suggest that the difference was statistically significant(P ? 0.05).(5)ROC analysis was used to analyze the relevant factors of ?2 grade RP,that is,ROC curve analysis of the volume of V5,and the area under the receiver operating curve of V5 was found to be AUC = 0.603,P = 0.025,the difference was statistically significant.Add the sensitivity and specificity corresponding to V5 of each patient.When the sensitivity is 0.588 and the specificity is 0.778,the sum of the two is the largest,the maximum is 1.366,and the corresponding V5 value is 54%.When comparing V5 <54% and V5 ? 54%,the total number was 34 cases and 18 cases respectively.Among them,there were 9 cases and 10 cases of patients with ?2 grade RP,and the incidence rates were 26.47% and 55.56%,respectively.Conclusion:The elderly non-surgical NSCLC patients who underwent IMRT treatment,V5 were shown to be associated with acute moderate-tosevere RP in the case of controlled V20?V30?MLD within safe rang.V5 may be a predictor of the occurrence of RP above level 2,which should be paid attention to.