ABSTRACT
BACKGROUND AND PURPOSE: Spinal cord toxicity can be dreaded complication while treating head and neck cancer by conventional radiotherapy. Cord sparing approach is applied by two phase planning in conventional head neck radiotherapy. In spite of cord sparing approach spinal cord still receives considerable scatter dose. Our study aims to do the volumetric analysis of spinal cord dosimetry and to correlate with the clinical findings. MATERIALS AND METHODS: Treatment planning was done in two phases. First phase treatment fields include gross disease- both tumor and involved nodes. in the second phase, treatment field shrinkage was done to cover the gross disease sparing the spinal cord. These fields are termed as off-cord fields. 42 patients with histological proven squamous cell carcinoma of the head and neck region were analysed with two groups. In Group A, 46 Gy was given in 23 fractions, and then tumor-boost with off-cord field received 24 Gy in 12 fractions. In Group B 50 Gy was prescribed in 25 fractions initially, then off-cord field given 20 Gy in 10 fractions to analyze theoutcome. Planning Computed tomography (CT) scan was done Philips Brilliance 16 slice CT scan machine, and contouring and dose calculation were done at ASHA treatment planning software. RESULTS: Maximum dose and dose at 1 cm3, 2 cm3, and 5 cm3 were calculated. Maximum dose to cord was 52.6 Gy (range 48.1-49.7 Gy) in Group A and 54.3 Gy (range 51.48-52.33 Gy) in Group B initially. Off-cord fields received mean dose 8.07 Gy (85.85% of maximum) in Group A and 5.47 Gy (86.84% of maximum) in Group B. At the end of 6 months from the last date of radiotherapy, grade 1 spinal cord toxicity found in two patients in Group A and one patient in Group B respectively (P = 0.55). Both groups received additional dose, which are higher than the prescribed dose, but no patients show significant spinal cord toxicity after 6 month of follow-up. CONCLUSION: Spinal cord received scatter dose which much higher than the predicted dose in conventional radiotherapy of head neck cancer. Short term follow up failed to establish clinical correlation with volumetric dose of spinal cord. Two phase cord sparing head neck radiation planning if practiced should be used with caution.
ABSTRACT
CONTEXT: Metastatic bone disease is a commonly encountered problem in oncology practice. The most useful and cost effective treatment is radiotherapy (RT). Different fractionation schedule of RT can be used to treat such condition. AIMS: Assessment of pain response in patients with vertebral bone metastasis after treating them with various radiation fractionations and to compare the toxicity profile in the treatment arms. SETTINGS AND DESIGN: A prospective randomized study was designed to include total 64 patients from July 2010 to May 2011. Patients with histopathologically proven primary malignancy having symptomatic secondary deposits to vertebra were selected for the study. Patients were randomized to two arms receiving multiple fraction of RT with 30 Gy in 10 fractions and 8 Gy in single fraction RT, respectively. MATERIALS AND METHODS: Patients with age >75 years, Karnofsky Performance Status (KPS) <40, features of cord compression were excluded from study. Initial pain response was assessed using Visual Analogue Scale (VAS) and compared using the same scale at weekly interval up to 1 month after treatment completion. RESULTS: Arm A comprised of 33 patients while 31 patients were enrolled in Arm B. Baseline patient characteristics were comparable. Eleven patients were lost to follow-up. Initial pain scores were 7.23 ± 0.765 and 7.51 ± 0.55 in arm A and arm B, respectively. Pain scores reduced significantly in both the arms after 1 month (4.39 ± 1.82 in arm A; 5.25 ± 2.39 in arm B). Time of initiation of pain response was earlier in arm A (P = 0.0281), statistically significant. Mild G-I toxicity was noted in both the arms but differences in two arms were not statistically significant (P = 0.49), no interruption of treatment was required because of side effects. CONCLUSIONS: Different fractionation of radiation has same response and toxicity in treatment of vertebral bone metastasis. Single fraction RT may be safely used to treat these cases as this is more cost effective and less time consuming. Studies may be conducted to find out particular subgroup of patients to be benefitted more by either fractionation schedule; however, our study cannot comment on that issue.
