Is a total dose of 54 Gy with radiochemotherapy sufficient for treatment of intermediate-risk volumes in nasopharyngeal cancer?

BACKGROUND: The mainstay treatment of nasopharyngeal cancer (NPC) is radiation therapy (RT). The doses and volumes may differ from center to center. Most studies and guidelines recommend a total dose of 60 Gy for elective nodal and peritumoral volume treatment. This retrospective analysis aimed to analyze whether a dose reduction to 54 Gy to this volume would be associated with a higher risk of recurrence. METHODS: A total of 111 patients treated by intensity-modulated radiotherapy (IMRT) and concurrent chemotherapy were retrospectively analyzed. The recurrent tumor volume was classified as "in field" if 95% of the recurrent volume was inside the 95% isodose, as "marginal" if 20-95% of the recurrence was inside the 95% isodose, or as "outside" if less than 20% of the recurrence was inside the 95% isodose. RESULTS: Median follow-up was 67 months (range 6-142). The 2­ and 5­year overall survival (OS) rates were 88.6% and 70%, respectively. The 2­year locoregional control (LRC), disease-free survival (DFS), and distant metastasis-free survival (DMFS) were 93.3%, 89.3%, and 87.4%, and the 5­year LRC, DFS, and DMFS were 86.8%, 74%, and 81.1%, respectively. Ten patients (9%) had a local and or regional recurrence. Half of the patients with locoregional failure had in-field recurrences. For primary tumor, there was no recurrence in the volume of 54 Gy. For regional lymph node volume, recurrence was detected in two (1.8%) patients in the volume of 54 Gy. CONCLUSION: These retrospective data suggest that a dose reduction may be possible for intermediate-risk volumes, especially for the primary site.

Interobserver agreement between interpretations of acute changes after lung stereotactic body radiotherapy.

PURPOSE: Stereotactic body radiation therapy (SBRT) is an effective treatment modality for inoperable early-stage lung cancer or metastatic lung lesions. Post-SBRT, acute radiological lung changes sometimes mimic tumor progression, so over-investigation may be applied. We aimed to reveal the interobserver agreement among physicians regarding acute radiographic changes on CT of the thorax obtained shortly after SBRT MATERIALS AND METHODS: Radiologic images of 20 lesions treated with SBRT were evaluated for acute lung changes. Two physicians, one senior and one junior, from diagnostic radiology, radiation oncology, nuclear medicine, and chest disease departments reviewed these images. The final interpretations were categorized as stable, regression/consolidation, progressive disease, and SBRT-related changes. The evaluations of the physicians were compared with the experienced reference radiation oncologist. The gold standard was accepted as the reference physician's final score. Unweighted Cohen's kappa (κ) coefficient was used for assessing interobserver agreement between physicians. RESULTS: The evaluations of the physicians were compared with the reference radiation oncologist. The strongest coherence coefficient was found with the senior radiation oncologist (κ: 0.72). The kappa coefficients between the junior radiation oncologist, junior nuclear medicine physician, and the reference physician were 0.61 and 0.55, respectively. The disciplines with the lowest kappa coefficients were junior chest disease and senior radiologist, and the kappa values were 0.37 and 0.44, respectively. CONCLUSION: Disciplines dealing with lung cancer treatment may not be aware of the various radiologic changes after SBRT or inexperienced in interpreting them from recurrence. Therefore, physicians must have detailed radiotherapy information such as planning target volume (PTV), dose/fractionation, etc. In addition, final evaluations should be performed in the multidisciplinary team dealing with the treatment of the patient.