| Part 1. Relative predictors for GI toxicity in pancreatic cancer patients undergoing TOMO hypofractioned radiationObjectiveTo identify clinical and dosimetric predictors correlated with GI toxicity in patients treated with TOMO hypofractioned radiation for pancreatic cancer.MethodsFrom January 2014 to January 2015, review the medical datas of 68 patients with pancreatic adenocarcinoma undergoing TOMO from Air Force General Hospital. All of the patients underwent simulated radiation treatment in the supine position with their arms up, and fixed with a thermoplastic body cast. Contrast CT scans were performed and ranged from the top of the liver to the upper edge of the ilium. Based on CT image,doctors contoured IGTV, GTV, CTV, ITV, PTV and OAR, with reference to MRI and PET-CT. It was required that 95% isodose line covered 100% of PTV and Dmax no more than 107% prescribed dose.110% isodose line no more than 3% of PTV. The dose delivered to the PTV, CTV, and GTV-IGTV of the primary pancreatic lesions was 50,60, and 70-80 Gy in 15-20 fractions, respectively.5 fractions per week. GI toxicity was scored using the CTCAE version 4.0. Estimate the severity and rate of GI toxicity from the radiation began and analysis the dosimetric and clinical predictors correlated with GI toxicity in patients undergoing TOMO hypofractioned radiation for pancreatic cancer.All data were computed using SPSS (version 20.0). Chi-square test was emplyed to analyze the count data. Spearman correlation analysis was conducted to assess prognostic influence of physical and clinical factors. Logistic regression models was conducted to assess predictors related with GI toxicity. The performances of the different DVH parameters to predict GI toxicity were assessed by constructing the ROC curve.Results1.Characteristic of GI toxicity:The median follow-up was 9 months (range,4-16 months). The median time to late grade Ⅱ GI toxicity was 3 months (range,3-9 months).61(89%) patients had acute GI toxicity.18 (26%) had grade Ⅱ acute GI toxicity and1(1%) had grade Ⅲ(Gastrointestinal hemorrhage) acute GI toxicity. whereas 37 (54%) patients developed late GI toxicity.17 (25%) had grade Ⅱ late GI toxicity and 1 (1%) had grade Ⅲ(Gastrointestinal hemorrhage) late GI toxicity. No patient had grade Ⅳ or higher GI toxicity.2.Spearman correlation analysis for factors associated with GI toxicity:On UVA, the volume, Dmean, D1-D10, V5-V40, and aV5-aV45 of duodenum were all correlated significantly with≥grade Ⅱ GI toxicity (P<0.05). On MVA,only the aV45 of the duodenum was an independent risk factor for≥grade Ⅱ GI toxicity (P<0.05). The ROC analysis was conducted with significant dosimetric predictors, which showed that the aV45 of the duodenum was the best predictor for grade Ⅱ or higher GI toxicity (Wald=4.643, P=0.031).The ROC analysis also showed that an aV45 of 0.5 cm3 was the optimal threshold to forecast grade Ⅱ or higher GI toxicity for the entire cohort. The grade Ⅱ or higher GI toxicity rate was 11.76%(2/17) versus 56.86%(29/51)for an aV45 ≤0.5 cm3 and an aV45>0.5 cm3, respectively (P=0.001, x 2= 10.454)ConclusionaV45 of duodenum is an independent factor in the occurrence of hypofractioned radiation related GI toxicity. aV45 of duodenum is very important in the forecast of the occurrence of GI toxicity in pancreatic cancer patients treated with TOMO hypofractioned radiation.Part 2. Predictive factors on GI toxicity based on endoscopy after TOMO hypofractioned radiation for pancreatic adenocarcinoma patientsObjectiveTo observe the endoscopic findings of GI toxicity in pancreatic cancer patients undergoing TOMO hypofractioned radiation and to identify clinical and dosimetric predictors correlated with GI toxicity.MethodsAnalysis the endoscopy before and after radiation of 23 pancreatic cancer patients received TOMO hypofractioned radiation treatment. All of the patients underwent simulated radiation treatment in the supine position with their arms up, and fixed using a thermoplastic body cast. Contrast CT scans were performed and ranged from the top of the liver to the upper edge of the ilium. Based on CT image,doctors contoured IGTV, GTV, CTV, ITV, PTV and OAR, with reference to MRI and PET-CT. It was required that 95% isodose line covered 100% of PTV and Dmax no more than 107% prescribed dose.110% isodose line no more than 3% of PTV. The dose delivered to the PTV, CTV, and GTV-IGTV of the primary pancreatic lesions was 50,60, and 70-80 Gy in 15-20 fractions, respectively.5 fractions per week. GI toxicity was scored using the CTCAE version 4.0 and criteria of GI toxicity in endoscopy. Estimate the severity and rate of GI toxicity from the radiation began and analysis the dosimetric and clinical predictors correlated with GI toxicity in patients undergoing TOMO hypofractioned radiation for pancreatic cancer. All data were computed using SPSS (version 20.0). Spearman correlation analysis was conducted to assess prognostic influence of physical and clinical factors. Logistic regression models was conducted to assess predictors related with GI toxicity.Results1. Characteristics of radiation acute GI toxicity based on CTCAE:11(43%) patients had acute GI toxicity.3(13%) patients experienced grade Ⅰ GI toxicity:nausea(n=1), vomiting (n=1),bloating(n=1).6(26%) patients experienced grade Ⅱ GI toxicity: nausea(n=3), vomiting (n=2), appetite descent(n=1).1(4%) patient experienced grade Ⅲ GI toxicity:nausea(n=1). no patient experienced grade IV or higher GI toxicity.2. Characteristics of radiation acute GI toxicity based on endoscopy:Grade Ⅰ gastric toxicity were found in 10 (43%) patients, no patient experienced grade Ⅰ duodenal toxicity. Grade Ⅱ gastric and duodenal toxicity were found in 2 (9%) and 3 (13%) patients, respectively; Grade Ⅲ gastric and duodenal toxicity were found in 3 (13.04%) and 1 (4.34%) patients, respectively; Grade Ⅳ gastric and duodenal toxicity based on endoscopy were found in 8 (34.78%) patients.11 patients have no radiation induced duodenal toxicity.3. Statistical results for predictors correlated with≥ grade Ⅱ toxicity based on endoscopy:On UVA, only Dmax of the duodenum was significantly related with≥ grade Ⅱ GI toxicity (P<0.05). On MVA, the statistical results showed no statistically significant between clinical、dosimetric predicitors and≥ grade Ⅱ GI toxicity (P> 0.05).4. Statistical results for predictors correlated with≥ grade Ⅲ GI toxicity based on endoscopy:On UVA, the Dmax, D1, D3, aV45 of the duodenum were significantly related with≥grade III toxicity (P<0.05). On MVA, the statistical results showed no statistically significant between clinical、dosimetric predicitors and≥ grade Ⅲ GI toxicity (P> 0.05).5. Statistical results for predictors correlated with≥grade IV GI toxicity based on endoscopy:On UVA, the Dmax, D1, D3, aV40,aV45 of the duodenum were significantly related with≥grade IV GI toxicity (P<0.05). On MVA, the statistical results showed no statistically significant between clinical、dosimetric predicitors and ≥grade IV GI toxicity (P>0.05).ConclusionThere was no correlation between subjective symptoms、clinical and dose-volume parameters and GI toxicity based on endoscopy after TOMO hypofractioned radiation treatment for pancreatic cancer and it is worth of a step further research. |
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