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Comparison of SUV-based Metabolic and CT Target Volumes in Esophageal Cancer Patients undergoing Radiation Therapy
I. J. Radiation Oncology d Biology d Physics
S262
Volume 72, Number 1, Supplement, 2008
median survival time (MST) was 12 months (range, 4-48 months), and the 1-year survival rate was 44%. A pretreatment CA 19-9 .1,200 U/mL (MST 13 vs. 8 months, p = 0.002), a posttreatment CA 19-9 .100 U/mL (MST 17 vs. 10 months, p = 0.0003), and a CA 19-9 decline of #40% (MST 13 vs. 10 months, p = 0.005) were the strongest and most unfavorable prognostic factors. In addition, patients with multiple unfavorable CA 19-9 levels had significantly worse outcomes than those with none. Conclusions: A CA 19-9 decline shows a correlation with a radiological response. The combination of a pretreatment CA 19-9 .1,200 U/mL, a posttreatment CA 19-9 .100 U/mL, and a CA 19-9 decline of #40% may possibly serve as a surrogate marker for poor survival in advanced PC receiving chemoradiotherapy. Author Disclosure: W. Koom, None; J. Seong, None; Y. Kim, None; H. Pyun, None; S. Song, None.
2206
Comparison of SUV-based Metabolic and CT Target Volumes in Esophageal Cancer Patients undergoing Radiation Therapy
S. Nagda, F. Vali, W. Hall, R. Hong, M. Gao, J. Sinacore, S. Lee, M. Shoup, B. Emami Loyola University Medical Center, Maywood, IL Purpose/Objective(s): The optimal metabolic target volume for use in positron emission tomography/computed tomography (PET/CT) based radiation therapy (RT) planning of esophageal cancer is unknown. We aim to compare various standardized uptake value (SUV)-based metabolic volumes and CT-based gross tumor volumes (GTV) at the level of the tumor epicenter. Materials/Methods: Twenty-two consecutive previously treated esophageal cancer patients with available FDG-PET imaging and CT-based RT plans were studied. A single patient with a pneumonitic infiltrate adjacent to the esophagus was excluded from analysis. The tumor epicenter - the region where the GTV is most clearly defined - was determined to be the axial slice containing the greatest tumor burden based on CT, endoscopy, and ultrasound. The GTV-epicenter was derived from the original GTV by reducing it superiorly and inferiorly, but not radially, to yield a 1-cm long sub-section of tumor at the epicenter. The PET scans were coregistered to the simulation CT scan. The PET volumes were delineated at various thresholds (SUV $2, $2.5, $3, $3.5; $40%, $45%, and $50% of the maximum SUV; $ liver mean SUV + 1, 2, 3, and 4 standard deviations) at the level of the GTV-epicenter. The ratio of the PET to GTV-epicenter volumes was determined. A conformality index (CI) defined as the intersection of two volumes divided by their union was calculated between the PET volumes and the GTV-epicenter. Means were analyzed by one-way ANOVA for repeated measures and further compared using paired t test for repeated measures. Results: Nineteen of 21 patients were T3N1. Average maximum SUV was 10.6 (4.1-25.4), mean GTV-epicenter was 26 cc (5-60) and PET was obtained on average, 6 days prior to simulation CT. Mean conformality indices were different (p = 0.021) and greatest for SUV 2.5 (0.46 ± 0.03) and mean liver + 4SD (0.48 ± 0.03) method. The mean PET to GTV-epicenter volume ratios ranged from 0.39 to 2.82 across all thresholds, being closest to 1 (ideal) at SUV 2.5 (1.18 ± 0.36) and liver mean + 4SD (1.09 ± 0.15) p = sig. In using the liver + 4SD method, those with SUV thresholds between 2.1-2.8 had a higher CI (0.51) than those outside of that range (0.42) (p = 0.16). Conclusions: Regardless of SUV thresholding method used i.e., absolute or relative to liver mean, a PET SUV threshold of approximately 2.5 yields the highest conformality index and best approximates the CT volume at the tumor epicenter. These findings may ultimately aid radiation oncologists in the delineation of the entire GTV in esophageal cancer patients. Author Disclosure: S. Nagda, None; F. Vali, None; W. Hall, None; R. Hong, None; M. Gao, None; J. Sinacore, None; S. Lee, None; M. Shoup, None; B. Emami, None.
2207
Radiation Therapy for Limited-stage Small-cell Esophageal Cancer 1
S. Yoshida , H. Ariga1, K. Nemoto2, Y. Ogawa1, K. Fujimoto1, K. Jingu1, C. Takahashi3, M. Kubozono4, K. Takeda1, S. Yamada1 1
Tohoku University, Sendai City, Japan, 2Yamagata University, Yamagata City, Japan, 3Osaki Citizen Hospital, Osaki City, Japan, 4Miyagi Cancer Center, Natori City, Japan Purpose/Objective(s): Small-cell esophageal carcinoma (SCEC) is rare and the prognosis for SCEC patients is poor. The treatment outcomes of limited-stage SCEC have not been studied extensively. This retrospective study investigated the treatment outcomes of 19 patients with limited-stage (Stages I-III) SCEC who had been treated with radiation therapy with or without chemotherapy. Materials/Methods: Between January 1985 and October 2007, 19 patients with limited stage, histologically proven small-cell esophageal carcinoma received radiation therapy with or without chemotherapy at Tohoku University Hospital and its affiliated hospitals. The staging workup included chest radiography, barium esophagography, endoscopic biopsy, brain, chest, and abdominal computed tomography, bone scintigraphy, and abdominal ultrasonography in all patients. The clinical stages were classified according to the Union International Contre le Cancer TNM classification system (2003). An opposing T-shaped field (including the supraclavicular region bilaterally and the entire mediastinum) was used in 9 patients, and a local field (6-8 cm wide, with a 3 cm margin at both the proximal and distal margins of the tumor) was used in 10 patients. Sixteen patients received chemotherapy concurrently with radiation therapy. A combination of cisplatin and VP-16 or cisplatin and 5-FU was used most frequently (in 7 patients each). The final follow-up was performed in October 2007. Survival times were calculated from the start of irradiation. The Kaplan-Meier method was used to calculate survival rates. The log-rank test was used to examine the prognostic factors. Results: The 1-, 2-, and 5-year overall survival rates were 45.0, 33.8, and 0%, respectively. The median survival time was 9.53 months. Distant metastasis was found in 15 patients (78.9%). Within 2 years, 88.6% of the patients had distant metastasis. The survival rates differed significantly between the 9 patients who were treated with T-shaped radiation (median survival 11.2 months) and the 10 patients who were treated with local field radiation (6.7 months) (p = 0.018). Metastasis developed earlier in patients who received local field radiation than in patients who received T-shaped radiation (p = 0.008). The survival rates differed significantly between the 11 patients who were treated with two or more courses of chemotherapy (median survival 11.2 months) and the 8 patients who were treated with 0 or 1 course of chemotherapy (median survival 6.7 months) (p = 0.023). Conclusions: Small-cell esophageal carcinoma should be regarded as a systemic disease, and two or more courses of chemotherapy should be given. Multi-institution studies are needed to obtain sufficiently large populations for investigating and optimizing local therapy for this disease. Author Disclosure: S. Yoshida, None; H. Ariga, None; K. Nemoto, None; Y. Ogawa, None; K. Fujimoto, None; K. Jingu, None; C. Takahashi, None; M. Kubozono, None; K. Takeda, None; S. Yamada, None.
S262
Volume 72, Number 1, Supplement, 2008
median survival time (MST) was 12 months (range, 4-48 months), and the 1-year survival rate was 44%. A pretreatment CA 19-9 .1,200 U/mL (MST 13 vs. 8 months, p = 0.002), a posttreatment CA 19-9 .100 U/mL (MST 17 vs. 10 months, p = 0.0003), and a CA 19-9 decline of #40% (MST 13 vs. 10 months, p = 0.005) were the strongest and most unfavorable prognostic factors. In addition, patients with multiple unfavorable CA 19-9 levels had significantly worse outcomes than those with none. Conclusions: A CA 19-9 decline shows a correlation with a radiological response. The combination of a pretreatment CA 19-9 .1,200 U/mL, a posttreatment CA 19-9 .100 U/mL, and a CA 19-9 decline of #40% may possibly serve as a surrogate marker for poor survival in advanced PC receiving chemoradiotherapy. Author Disclosure: W. Koom, None; J. Seong, None; Y. Kim, None; H. Pyun, None; S. Song, None.
2206
Comparison of SUV-based Metabolic and CT Target Volumes in Esophageal Cancer Patients undergoing Radiation Therapy
S. Nagda, F. Vali, W. Hall, R. Hong, M. Gao, J. Sinacore, S. Lee, M. Shoup, B. Emami Loyola University Medical Center, Maywood, IL Purpose/Objective(s): The optimal metabolic target volume for use in positron emission tomography/computed tomography (PET/CT) based radiation therapy (RT) planning of esophageal cancer is unknown. We aim to compare various standardized uptake value (SUV)-based metabolic volumes and CT-based gross tumor volumes (GTV) at the level of the tumor epicenter. Materials/Methods: Twenty-two consecutive previously treated esophageal cancer patients with available FDG-PET imaging and CT-based RT plans were studied. A single patient with a pneumonitic infiltrate adjacent to the esophagus was excluded from analysis. The tumor epicenter - the region where the GTV is most clearly defined - was determined to be the axial slice containing the greatest tumor burden based on CT, endoscopy, and ultrasound. The GTV-epicenter was derived from the original GTV by reducing it superiorly and inferiorly, but not radially, to yield a 1-cm long sub-section of tumor at the epicenter. The PET scans were coregistered to the simulation CT scan. The PET volumes were delineated at various thresholds (SUV $2, $2.5, $3, $3.5; $40%, $45%, and $50% of the maximum SUV; $ liver mean SUV + 1, 2, 3, and 4 standard deviations) at the level of the GTV-epicenter. The ratio of the PET to GTV-epicenter volumes was determined. A conformality index (CI) defined as the intersection of two volumes divided by their union was calculated between the PET volumes and the GTV-epicenter. Means were analyzed by one-way ANOVA for repeated measures and further compared using paired t test for repeated measures. Results: Nineteen of 21 patients were T3N1. Average maximum SUV was 10.6 (4.1-25.4), mean GTV-epicenter was 26 cc (5-60) and PET was obtained on average, 6 days prior to simulation CT. Mean conformality indices were different (p = 0.021) and greatest for SUV 2.5 (0.46 ± 0.03) and mean liver + 4SD (0.48 ± 0.03) method. The mean PET to GTV-epicenter volume ratios ranged from 0.39 to 2.82 across all thresholds, being closest to 1 (ideal) at SUV 2.5 (1.18 ± 0.36) and liver mean + 4SD (1.09 ± 0.15) p = sig. In using the liver + 4SD method, those with SUV thresholds between 2.1-2.8 had a higher CI (0.51) than those outside of that range (0.42) (p = 0.16). Conclusions: Regardless of SUV thresholding method used i.e., absolute or relative to liver mean, a PET SUV threshold of approximately 2.5 yields the highest conformality index and best approximates the CT volume at the tumor epicenter. These findings may ultimately aid radiation oncologists in the delineation of the entire GTV in esophageal cancer patients. Author Disclosure: S. Nagda, None; F. Vali, None; W. Hall, None; R. Hong, None; M. Gao, None; J. Sinacore, None; S. Lee, None; M. Shoup, None; B. Emami, None.
2207
Radiation Therapy for Limited-stage Small-cell Esophageal Cancer 1
S. Yoshida , H. Ariga1, K. Nemoto2, Y. Ogawa1, K. Fujimoto1, K. Jingu1, C. Takahashi3, M. Kubozono4, K. Takeda1, S. Yamada1 1
Tohoku University, Sendai City, Japan, 2Yamagata University, Yamagata City, Japan, 3Osaki Citizen Hospital, Osaki City, Japan, 4Miyagi Cancer Center, Natori City, Japan Purpose/Objective(s): Small-cell esophageal carcinoma (SCEC) is rare and the prognosis for SCEC patients is poor. The treatment outcomes of limited-stage SCEC have not been studied extensively. This retrospective study investigated the treatment outcomes of 19 patients with limited-stage (Stages I-III) SCEC who had been treated with radiation therapy with or without chemotherapy. Materials/Methods: Between January 1985 and October 2007, 19 patients with limited stage, histologically proven small-cell esophageal carcinoma received radiation therapy with or without chemotherapy at Tohoku University Hospital and its affiliated hospitals. The staging workup included chest radiography, barium esophagography, endoscopic biopsy, brain, chest, and abdominal computed tomography, bone scintigraphy, and abdominal ultrasonography in all patients. The clinical stages were classified according to the Union International Contre le Cancer TNM classification system (2003). An opposing T-shaped field (including the supraclavicular region bilaterally and the entire mediastinum) was used in 9 patients, and a local field (6-8 cm wide, with a 3 cm margin at both the proximal and distal margins of the tumor) was used in 10 patients. Sixteen patients received chemotherapy concurrently with radiation therapy. A combination of cisplatin and VP-16 or cisplatin and 5-FU was used most frequently (in 7 patients each). The final follow-up was performed in October 2007. Survival times were calculated from the start of irradiation. The Kaplan-Meier method was used to calculate survival rates. The log-rank test was used to examine the prognostic factors. Results: The 1-, 2-, and 5-year overall survival rates were 45.0, 33.8, and 0%, respectively. The median survival time was 9.53 months. Distant metastasis was found in 15 patients (78.9%). Within 2 years, 88.6% of the patients had distant metastasis. The survival rates differed significantly between the 9 patients who were treated with T-shaped radiation (median survival 11.2 months) and the 10 patients who were treated with local field radiation (6.7 months) (p = 0.018). Metastasis developed earlier in patients who received local field radiation than in patients who received T-shaped radiation (p = 0.008). The survival rates differed significantly between the 11 patients who were treated with two or more courses of chemotherapy (median survival 11.2 months) and the 8 patients who were treated with 0 or 1 course of chemotherapy (median survival 6.7 months) (p = 0.023). Conclusions: Small-cell esophageal carcinoma should be regarded as a systemic disease, and two or more courses of chemotherapy should be given. Multi-institution studies are needed to obtain sufficiently large populations for investigating and optimizing local therapy for this disease. Author Disclosure: S. Yoshida, None; H. Ariga, None; K. Nemoto, None; Y. Ogawa, None; K. Fujimoto, None; K. Jingu, None; C. Takahashi, None; M. Kubozono, None; K. Takeda, None; S. Yamada, None.