Byung-Sik Nah

Metabolic Response of Lymph Nodes Immediately After RT Is Related With Survival Outcome of Patients With Pelvic Node-Positive Cervical Cancer Using Consecutive [18F]fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography

PURPOSE To evaluate the metabolic response of uterine cervix and pelvic lymph nodes (LNs) using consecutive 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) immediately after RT and to correlate survival outcome with the metabolic response. METHODS AND MATERIALS We retrospectively reviewed 48 patients with cervical cancer who had positive pelvic LNs by preradiation therapy (pre-RT) PET/CT. All patients underwent PET/CT scans immediately after RT (inter-RT PET/CT) after median 63 Gy to the gross LNs. The metabolic response of the LNs was assessed quantitatively and semiquantitatively by measurement of the maximal standardized uptake value (SUVmax). RESULTS Classifying the metabolic response of all nodal lesions, 37 patients (77%) had LNs with complete metabolic response on the inter-RT PET/CT (LNCMRi), and 11 patients had a non-LNCMRi, including 4 patients with progressive metabolic disease. The overall 3-year survival rates were 83% for the patients with LNCMRi and 73% for the non-LNCMRi group (P=.038). The disease-free survival for patients with LNCMRi were significantly better than that for the non-LNCMRi group (71% vs 18%, respectively, P<.001). The 3-year distant metastasis-free survival rates were 79% for the patients with LNCMRi and 27% for the non-LNCMRi group (P<.001). There were no statistically significant differences in overall survival (76% vs 86%, respectively, P=.954) and disease-free survival rates (58% vs 61%, respectively, P=.818) between the CMR of primary cervical tumor and the non-CMR groups. CONCLUSIONS The results showed a significant correlation between survival outcome and the interim metabolic response of pelvic LNs. CMR of nodal lesion on inter-RT PET/CT had excellent overall survival, disease-free survival and distant metastasis-free survival rates. This suggested that PET/CT immediately after RT can be a useful tool for the evaluation of the interim response of the LNs and identify a subset of patients with a high risk of recurrence and poor survival in patients with cervical cancer with initial positive LNs.

The metabolic response using 18F-fluorodeoxyglucose-positron emission tomography/computed tomography and the change in the carcinoembryonic antigen level for predicting response to pre-operative chemoradiotherapy in patients with rectal cancer.

BACKGROUND AND PURPOSE To predict tumor regression in pre-operative chemoradiotherapy (CRT) using (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) and serum carcinoembryonic antigen (CEA) in patients with rectal cancer. MATERIALS AND METHODS The metabolic response of the tumor was assessed by determining the maximal standardized uptake value (SUV(max)), absolute difference (ΔSUV(max)), and SUV reduction ratio (SRR) on pre- and post-CRT PET/CT scans. The serum CEA, absolute difference (ΔCEA), and the CEA reduction ratio (CRR) were also determined. A receiver-operating characteristic (ROC) curve was generated. RESULTS Of all seventy two patients, mean pre- and post-CRT SUV(max) was 14.9 and 5.8, respectively. The mean pre- and post-CRT CEA level was 15.5 ng/ml and 5.4 ng/ml, respectively. Forty-three patients (59.8%) were classified as responders (Dworaks tumor regression grade 3-4) and 36 patients (50%) achieved tumor down-staging. ROC analysis showed that both post-CRT SUV(max) and SRR were predictive factors for responders (p=0.03 and p=0.02, respectively). A threshold of post-CRT SUV(max) was 5.4 and that of SRR was 53.1%. Pre-CRT SUV(max), ΔSUV(max), and all parameters in regard to CEA were not significant in ROC analysis. CONCLUSIONS The post-CRT SUV(max) and SRR are potential factors for predicting tumor response in pre-operative CRT. The patients with lower post-CRT SUV(max) and higher SRR could be expected to achieve maximum tumor regression after pre-operative CRT in this study.

VEGF as a Predictor for Response to Definitive Chemoradiotherapy and COX-2 as a Prognosticator for Survival in Esophageal Squamous Cell Carcinoma

We investigated the patterns of pretreatment expression of the epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) by immunohistochemical staining and determined their correlation with treatment response and survival in 44 patients with esophageal squamous cell carcinoma (ESCC) treated with definitive concurrent chemoradiotherapy (CCRT). The definitive CCRT consisted of a median dose of 54 Gy (range: 40.0-68.4 Gy) and two cycles of concurrent administration of mostly 5-fluorouracil + cisplatinum. High expression of EGFR, VEGF, and COX-2 was found in 79.5%, 31.8%, and 38.6%, respectively. The Cox regression analysis for overall survival (OS) showed that both the treatment response and COX-2 expression were significant. The 3-yr OS rates of patients that achieved a complete response and those that did not were 46.7% and 5.3%, respectively (P = 0.006). The logistic regression analysis for treatment response with various parameters showed that only a high expression of VEGF was significantly associated with a complete response. Unlike other well-known studies, higher expression of VEGF was significantly correlated with a complete response to CCRT in this study. However, higher expression of COX-2 was significantly associated with shorter survival. These results suggest that VEGF might be a predictive factor for treatment response and COX-2 a prognostic factor for OS in patients with ESCC after definitive CCRT.

Concurrent chemoradiotherapy with cisplatin and fluorouracil for locally advanced hypopharyngeal carcinoma

Conclusions. The concurrent administration of cisplatin and fluorouracil (CCRT) during radiotherapy after induction chemotherapy had better results than induction chemotherapy followed by radiotherapy alone (CT+RT) for overall survival, laryngeal preservation, and locoregional control in patients with locally advanced hyopharyngeal cancer. Objectives. To report treatment results comparing CCRT with CT+RT in locally advanced hypopharyngeal cancer. Patients and methods. Sixty-six consecutive patients treated with curative intent were analyzed retrospectively. Thirty-eight patients were treated with induction chemotherapy followed by definitive RT, and 28 patients with induction chemotherapy followed by concurrent chemoradiotherapy. All patients had more than three cycles of continuous infusion of cisplatin and 5-fluorouracil every 3 weeks. The median dose of irradiation was 70 Gy in the CT+RT group and 68.4 Gy in the CCRT group, respectively. Results. The overall 5-year survival rates were 24% for the CT+RT group and 42% for the CCRT group (p=0.031). The 3-year pharyngolaryngectomy-free survival rates were 32% for the CT+RT group and 63% for the CCRT group (p=0.032). The 3-year locoregional control rate for CCRT was significantly better than that for the CT+RT (52% vs 23%, p=0.004). Acute hematologic toxicity appeared in 39% of the CT+RT patients and 75% of the CCRT patients.

Results of Curative Radiation Therapy with or without Chemotherapy for Stage III Unresectable Non-Small Cell Lung Cancer

PURPOSE We retrospectively analyzed the patients who received curative radiotherapy for unresectable stage III NSCLC to investigate the impact of chemotherapy. MATERIALS AND METHODS From 1998 to 2001, the records of 224 patients who completed curative radiotherapy for NSCLC were reviewed. There were 210 males and 14 females, and their median age was 64 years (range 38 approximately 83). 54 patients had stage IIIA disease and 170 patients had stage IIIB disease. Conventional radiotherapy was given and the radiation dose ranged from 50 approximately 70 Gy with a median of 60 Gy, and chemotherapy was combined for 116 patients (52%). RESULTS The median survival, the 2-year, and 5-year actuarial survival rates of all 224 patients were 15 months, 30%, and 7%, respectively. The median survival of the patients with stage IIIA and IIIB disease were 21 months and 13 months, respectively (p=0.14). The median survival of patients who received chemoradiation was 18 months compared to 14 months for the patients who received RT alone (p=0.02). Among the chemoradiation group of patients, the median survival time of the patients who received 1 to 3 cycles of chemotherapy was 16 months and that for the patients who received more than 3 cycles was 22 months (p=0.07). We evaluated the effects of the timing of chemoradiation in 57 patients who received more than 3 cycles of chemotherapy. The median survival of the patients with the concurrent sequence was 25 months and that for the patients with the sequential chemotherapy was 19 months (p=0.81). CONCLUSIONS For advanced stage III non-small cell lung cancer patients who completed the curative radiotherapy, the addition of chemotherapy improved the survival compared to the patients who received radiotherapy alone.

Assessment of Tumor Regression by Consecutive Pelvic Magnetic Resonance Imaging and Dose Modification during High-Dose-Rate Brachytherapy for Carcinoma of the Uterine Cervix

PURPOSE To assess tumor regression, as determined by pelvic magnetic resonance imaging (MRI), and evaluate the efficacies and toxicities of the interim brachytherapy (BT) modification method, according to tumor regression during multi-fractionated high-dose-rate (HDR) BT for uterine cervical cancer. MATERIALS AND METHODS Consecutive MRI studies were performed pre-radiotherapy (RT), pre-BT and during interfraction of BT (inter-BT) in 69 patients with cervical cancer. External beam radiotherapy (EBRT) was performed, using a 10 MV X-ray, in daily fraction of 1.8 Gy with 4-fields, 5 d/wk. Radiation was delivered up to 50.4 Gy, with midline shielding at around 30.6 Gy. Of all 69 patients, 50 received modified interim BT after checking the inter-BT MRI. The BT was delivered in two sessions; the first was composed of several 5 Gy fractions to point A, twice weekly, using three channel applicators. According to the three measured orthogonal diameters of the regressed tumor, based on inter-BT MR images, the initial BT plan was modified, with the second session consisting of a few fractions of less than 5 Gy to point A, using a cervical cylinder applicator. RESULTS The numbers of patients in FIGO stages Ib, IIa, IIb and IIIb+IVa were 19 (27.5%), 18 (26.1%), 27 (39.2%) and 5 (7.2%), respectively. Our treatment characteristics were comparable to those from the literatures with respect to the biologically effective dose (BED) to point A, rectum and bladder as reference points. In the regression analysis a significant correlation was observed between tumor regression and the cumulative dose to point A on the follow-up MRI. Nearly 80% regression of the initial tumor volume occurred after 30.6 Gy of EBRT, and this increased to 90% after an additional 25 Gy in 5 fractions of BT, which corresponds to 73.6 Gy of cumulative BED(10) to point A. The median total fraction number, and those at the first and second sessions of BT were 8 (5 approximately 10), 5 (3 approximately 7) and 3 (1 approximately 5), respectively. The median follow-up time was 53 months (range, 9 approximately 66 months). The 4-year disease-free survival rate of all patients was 86.8%. Six (8.7%) patients developed pelvic failures, but major late complications developed in only two (2.9%). CONCLUSION Our study shows that effective tumor control, equivalent survival and low rates of major complications can be achieved by modifying the fraction size during BT according to tumor regression, as determined by consecutive MR images. We recommend checking the follow-up MRI at a cumulative BED(10) of around 65 Gy to point A, with the initial BT modified at a final booster BT session.

SU-GG-T-142: Organ Motional Effect On the Dose Distribution in Intensity Modulated Radiation Therapy

Purpose: The respiratory organ motional effect on the dosimetric accuracy in IMRT was analyzed and the function of RPM gating system in reducing the organ motional effect was evaluated with the respiration simulating phantom. Method and Materials: The phantom system which can simulate respiratory organ motion was manufactured. Total 4 IMRT plans for livercancer were evaluated in the 3 cases of situation that were a static status, a no‐gated free‐breathing motion and a gated radiotherapy with RPM system. The motional range was set 1.6 cm considering the real movement of tumor in the fluoroscopic images and respiratory movement cycle was fixed to 5 sec. The dosimetric accuracy of all the fields of IMRT plan was analyzed with MapCHECK (SunNuclear, USA) device laid on the moving table of the phantom. The comparison analysis between a dose distribution in plan and a real one in treatment was done with a coronal dose distribution in the depth of diode detector arrays in the MapCHECK. The decision of pass in each measurement points was verified by a gamma evaluation in the criteria of 3 mm distance and 3% dose.Results: The average pass rates in each motional status are 98.4% at static case, 49.9% at motional case and 97.9% at gated IMRT case. These data shows that the RPM gated radiation therapy decreased a large amount of dosimetric error due to the organ motional effect in IMRT.Conclusion: The considerable dosimetric error due to organ motion was occurred even in the motional range (1.6 cm) of normal breathing condition. This organ motional error could be reduced with a RPM gating system and the gated radiation therapy with a proper gated phase should be performed for the IMRT of abdominal lesions which are moved by a respiration.

Evaluation on the Functions of Setup Error Correction in the On-Board Imager (OBI) System

On-Board Imager (OBI) System which is attached to the both sides of the linear accelerator is considered as a proper tool to deliver the Image Guided Radiation Therapy (IGRT). In this study, the accuracy of the setup error correction using the OBI system is evaluated. The evaluated OBI system was the part of the Clinac iX (Varian, USA) and the accuracy of setup error correction was analyzed using the phantom provided by Varian for the quality assurance of the OBI system. In the treatment room, the phantom was located with different positions compared with the one in a test plan with a combined random shift variation in the direction of longitudinal, vertical, and lateral of couch. Additionally, the couch rotational variation was also considered. The shift variation was limited to the value of 2 cm in each direction and 2 degree was the maximum value in the rotational variation. The operation for the setup error correction in the OBI system was performed by the dosimetrist and therapist who do not know the real variation of the phantom setup location in the treatment room for the blind test. The total number of tests for the shift variations was 20 and five cases were analyzed for the couch rotational variation. The average of absolute correction errors in the case of shift variations only were 0.70 mm (longitudinal), 0.70 mm (lateral) and 0.85 mm (vertical). When the rotation was also varied combined with the shift variations, the average values were 2.8 mm (longitudinal), 3.2 mm (lateral), 2.6 mm (vertical) and 0.4 degree. The function of setup error correction in the OBI system of Clinac iX showed the verification of the accuracy in the cases of shift variations but could not be evaluated as a proper accuracy in the correction of the rotational variations.