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Purpose: Assuming F-18-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET)/computed tomography (CT) to be more accurate in representing the true disease extent than CT alone, we prospectively designed this study to evaluate how the addition of FDG-PET influences CT-based radiotherapy planning for locally recurrent nasopharyngeal carcinoma., Patients and Methods: All patients underwent FDG-PET/CT simulation scans. For each patient, the gross tumor volume (GTV) was separately delineated with or without the addition of PET information and defined as GTV PET/CT and GTV CT, respectively. Corresponding planning target volumes (PTV) were generated for the GTV CT (PTV(CT)) and GTV PET/CT (PTV PET/CT). Three-dimensional conformal radiotherapy plans were separately created for PTV CT and PTV PET/CT. To assess the potential geographic miss of the PET/CT-based disease in CT-based treatment planning, the size and location of the GTV PET/CT, PTV(PET/CT), and PTV(CT) were analyzed, and the three-dimensional conformal radiotherapy plans created using the PTV CT were evaluated with the GTV PET/CT and PTV PET/CT information., Results: A total of 43 patients were enrolled in this study. Distant metastasis was found in 4 patients with the addition of the PET information. The 39 patients without distant metastasis proceeded to three-dimensional conformal radiotherapy planning. Inadequate coverage of the GTV PET/CT and PTV PET/CT by the PTV CT occurred in 7 (18%) and 20 (51%) patients, respectively. This resulted in <95% of the GTV(PET/CT) and PTV PET/CT receiving >or=95% of the prescribed dose in 4 (10%) and 13 (33%) patients, respectively., Conclusions: The addition of FDG-PET information might influence CT-based radiotherapy planning for locally recurrent nasopharyngeal carcinoma by altering the definition of the target volume, with the potential to avoid a geographic miss of true disease.

Objective: To explore the clinical value of (18)F-fluorodeoxyglucose positron emission tomography ((18)FDG-PET) in three-dimensional conformal radiotherapy (3D-CRT) for locally residual and recurrent nasopharyngeal carcinoma (NPC)., Methods: Between July 1998 and October 2000, 36 patients with recurrent or residual NPC confirmed by biopsy after initial radiotherapy underwent treatment with 3D-CRT. CT simulation was performed and (18)FDG-PET carried out for delineating the gross tumor volume (GTV) in all the patients. The radiotherapy was designed by 3D treatment planning system and dose-volume histogram (DVH) was used to verify and optimize the radiation plan. Acute and late radiation injuries, survival rates and GTV delineated by CT and (18)FDG-PET were observed in all the cases after the treatment., Results: In comparison with CT simulation, (18)FDG-PET delineated similar GTV in 36.1% (13/36) cases, larger and smaller GTV in 16.7% (6/36) and 47.2% (17/36) of the cases, respectively. After 3D-CRT, 97.2%, 75.0%, and 58.3% of the patients were free of evidence of 1-, 2-, and 3-year local failure, respectively, and the 1-, 2-, and 3-year survival rate of the patients were 94.4%, 86.1%, and 72.0%. The 1-, 2-, 3-year tumor-free survival rates were 85.7%, 76.6%, and 56.1% respectively. Acute xerostomia, nasopharyngitis and oropharyngitis were the most common complications in relation to the radiation, but all within acceptable range of grades 1 or 2. The lesions resulting from the radiation included hearing loss, trismus, dysphagia, chronic sinusitis, and cranial neuropathy, with the incidences of 5.6% (2/36), 25.0% (9/36), 8.3% (3/36), 33.3% (12/36), and 13.9% (5/36) respectively., Conclusions: 3D-CRT combined with (18)FDG-PET for delineation of GTV is effective and feasible in the treatment of locally residual or recurrent nasopharyngeal carcinoma after initial radiotherapy, producing good responses without serious complications.

Purpose: To assess the dosimetric and clinical results of three-dimensional conformal radiotherapy (3D CRT) for locally recurrent nasopharyngeal carcinoma (NPC)., Methods: A total of 86 patients with locally recurrent NPC were retreated with 3D CRT. The median prescribed dose was 68 Gy with 2 Gy per fractionation. Dosimetric quality was evaluated with dose distribution in planning target volume (PTV) and specified organs at risk (OAR), dose conformity index (CI) and dose homogeneity index (HI). The actuarial rate of local failure-free (LFF), overall survival (OS) and major late toxicities (MLT) were estimated with Kaplan-Meier method. Multivariate analysis for prognosis was performed using the Cox regression proportional hazards model., Results: The mean dose to PTV averaged 66.8 Gy, and the dose to specified OAR was acceptable. The average value of CI and HI was 0.59 and 9.1%. The 5-year actuarial rate of LFF and OS was 71 and 40%, respectively. The 5-year actuarial incidence of MLT>or=Grade 3 and >or=Grade 4 were 100 and 49%, respectively. The major prognostic factors were T stage and the size of gross tumor volume (GTV). Advanced T stage and large GTV volume were associated with poor LFF and OS and high risk of MLT., Conclusion: The dosimetric quality of 3D CRT for locally recurrent NPC is generally excellent. A relatively high local control was achieved with this technique. However, the incidence of late toxicities were not found to decrease as originally expected. Early diagnosis of the recurrence and reasonable definition of the target volume are crucial to achieve a better outcome.

Objective: To evaluate the effects of 3-dimensional conformal radiation therapy combined with chemotherapy for rectal cancer of postoperative local recurrence., Methods: Fifty-six rectal cancer patients of postoperative local recurrence were treated with 3-dimensional conformal radiotherapy (66 approximately 68 Gy in 2 Gy daily fraction) combined with chemotherapy (5-Fu 0.75, Days 1 - 5 and Days 29 - 33; Cisplatin 40 mg, Days 1 - 3 and Days 29 - 31). Acute and late radioreactions and survival rates were observed. Kaplan-Meier method was used for survival analysis., Results: The 1, 2, 3 years local control rate was 87.5%, 66.1%, 38.2%, respectively. The 1, 2, 3 years disease-free survival and overall were 82.7%, 56.6%, 30.1% and 88.3%, 66.8%, 44.2%, respectively. The median survival was 25.3 months. Acute small enteritis were the most common but acceptable radioreactions Grade 1 approximately 2. No late radioreactions occurred., Conclusions: 3-dimensional conformal radiotherapy combined with chemotherapy can be considered as an effective and feasible approach to cancer patients of postoperative local recurrence.

Objective: To explore the significance of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18FDG-PET) in the diagnosis of the recurrence or fibrosis of nasopharyngeal carcinoma at the parapharyngeal space after radiotherapy., Methods: Thirty-two patients having received radiotherapy for nasopharyngeal carcinoma at the parapharyngeal space underwent 18FDG-PET in parallel with CT and magnetic resonance imaging (MRI) examinations to detect the recurrence or fibrosis of the tumors after the treatment, when the latter two examinations had failed to yield definite results. After all the imaging examinations, CT-guided puncture biopsy was performed in each case to observe the sensitivity, specificity and accuracy of the examinations., Results: The sensitivity, specificity and accuracy were 79.16%, 75.00%, and 78.13% respectively for CT examination, and were 83.33%, 87.50%, and 84.38% for MRI. 18FDG-PET had the best sensitivity, specificity and accuracy in detecting tumor recurrence, which were 95.83%, 87.50%, and 93.75% respectively., Conclusion: 18FDG-PET can be considered in cases of suspected recurrence of nasopharyngeal carcinoma at the parapharyngeal space after radiotherapy, and CT and MRI examinations either used alone or in combination may also reach definite diagnosis with the help of CT-guided biopsy.

Objective: To evaluate the feasibility of reirradiation for recurrent nasopharyngeal carcinoma (NPC) using three-dimensional conformal radiotherapy (3-D CRT) and to assess its short-term therapeutic effects and the lesions in association with radiation exposure., Methods: Between July 1998 and October 2000, 42 NPC patients with recurrence after their initial radiotherapy received retreatment with 3-D CRT. The radiotherapy was designed by 3-D treatment planning system and dose-volume histogram (DVH) was used to verify and optimize the radiation plan. Multileaf collimation technique and immobilization devices to fix the position of the head were used to achieve validity and accuracy of radiotherapy. The planning target volume (PTV) encompassed 7~10 mm safety margin, with a median volume of PTV of 47.6 cm3 (27.9 to 61.8 cm3), and 5 to 7 static conformal portals were delivered with coplanar or non-coplanar irradiation technique. The prescription dose-fractionation-time was 60-70 Gy/24-28 F/5-5.5 weeks, with the median follow-up time after 3-D CRT of 24 months (ranging from 10 to 38 months)., Results: No evidence of local failure was found in 85.7 % of the cases after 3-D CRT and the 2-year survival rate was 73.8 %. The lesions resulting from the radiation included hearing loss, trismus, dysphagia, chronic sinusitis, and cranial neuropathy, at a rate of 7.1 %, 35.7 %, 7.1 %, 28.6 %, and 21.4 % respectively., Conclusion: 3-D CRT is effective and feasible to treatment of recurrent NPC after initial radiotherapy, producing good responses without serious complications. The long-term survival and possible specific injury, however, need to be further investigated.