PURPOSE: To determine the impact of body mass index (BMI) on daily setup variations and frequency of imaging necessary for patients with endometrial cancer treated with adjuvant intensity-modulated radiotherapy (IMRT) with daily image guidance. METHODS AND MATERIALS: The daily shifts from a total of 782 orthogonal kilovoltage images from 30 patients who received pelvic IMRT between July 2008 and August 2010 were analyzed. The BMI, mean daily shifts, and random and systematic errors in each translational and rotational direction were calculated for each patient. Margin recipes were generated based on BMI. Linear regression and spearman rank correlation analysis were performed. To simulate a less-than-daily IGRT protocol, the average shift of the first five fractions was applied to subsequent setups without IGRT for assessing the impact on setup error and margin requirements. RESULTS: Median BMI was 32.9 (range, 23-62). Of the 30 patients, 16.7% (n = 5) were normal weight (BMI <25); 23.3% (n = 7) were overweight (BMI ≥ 25 to <30); 26.7% (n = 8) were mildly obese (BMI ≥ 30 to <35); and 33.3% (n = 10) were moderately to severely obese (BMI ≥ 35). On linear regression, mean absolute vertical, longitudinal, and lateral shifts positively correlated with BMI (p = 0.0127, p = 0.0037, and p < 0.0001, respectively). Systematic errors in the longitudinal and vertical direction were found to be positively correlated with BMI category (p < 0.0001 for both). IGRT for the first five fractions, followed by correction of the mean error for all subsequent fractions, led to a substantial reduction in setup error and resultant margin requirement overall compared with no IGRT. CONCLUSIONS: Daily shifts, systematic errors, and margin requirements were greatest in obese patients. For women who are normal or overweight, a planning target margin margin of 7 to 10 mm may be sufficient without IGRT, but for patients who are moderately or severely obese, this is insufficient.
PURPOSE: To determine the impact of body mass index (BMI) on daily setup variations and frequency of imaging necessary for patients with endometrial cancer treated with adjuvant intensity-modulated radiotherapy (IMRT) with daily image guidance. METHODS AND MATERIALS: The daily shifts from a total of 782 orthogonal kilovoltage images from 30 patients who received pelvic IMRT between July 2008 and August 2010 were analyzed. The BMI, mean daily shifts, and random and systematic errors in each translational and rotational direction were calculated for each patient. Margin recipes were generated based on BMI. Linear regression and spearman rank correlation analysis were performed. To simulate a less-than-daily IGRT protocol, the average shift of the first five fractions was applied to subsequent setups without IGRT for assessing the impact on setup error and margin requirements. RESULTS: Median BMI was 32.9 (range, 23-62). Of the 30 patients, 16.7% (n = 5) were normal weight (BMI <25); 23.3% (n = 7) were overweight (BMI ≥ 25 to <30); 26.7% (n = 8) were mildly obese (BMI ≥ 30 to <35); and 33.3% (n = 10) were moderately to severely obese (BMI ≥ 35). On linear regression, mean absolute vertical, longitudinal, and lateral shifts positively correlated with BMI (p = 0.0127, p = 0.0037, and p < 0.0001, respectively). Systematic errors in the longitudinal and vertical direction were found to be positively correlated with BMI category (p < 0.0001 for both). IGRT for the first five fractions, followed by correction of the mean error for all subsequent fractions, led to a substantial reduction in setup error and resultant margin requirement overall compared with no IGRT. CONCLUSIONS: Daily shifts, systematic errors, and margin requirements were greatest in obesepatients. For women who are normal or overweight, a planning target margin margin of 7 to 10 mm may be sufficient without IGRT, but for patients who are moderately or severely obese, this is insufficient.
Authors: P Pérez-Segura; J E Palacio; L Vázquez; S Monereo; R de Las Peñas; P Martínez de Icaya; C Grávalos; A Lecube; A Blasco; J M García-Almeida; I Barneto; A Goday Journal: Clin Transl Oncol Date: 2017-01-10 Impact factor: 3.405
Authors: A Smits; J McGrane; A Lopes; E Kent; R Bekkers; L Massuger; N Simpson; K Galaal Journal: Int J Clin Oncol Date: 2017-06-15 Impact factor: 3.402
Authors: Angeles Alvarez Secord; Vic Hasselblad; Vivian E Von Gruenigen; Paola A Gehrig; Susan C Modesitt; Victoria Bae-Jump; Laura J Havrilesky Journal: Gynecol Oncol Date: 2015-10-31 Impact factor: 5.482