Planning Target Volumes Determine Weight Loss in Highly Conformal Radiation Therapy in Head and Neck Cancers – A Validation Study

Clinical Oncology xxx (2014) 1 Contents lists available at ScienceDirect

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Letter

Planning Target Volumes Determine Weight Loss in Highly Conformal Radiation Therapy in Head and Neck Cancers e A Validation Study Sir d We recently published our experience in determining the factors predicting for weight loss in a series of 103 patients treated with highly conformal radiotherapy or chemoradiotherapy (CRT) for head and neck cancer [1]. We found that the planning target volumes (PTV) as well as the use of CRT were independent predictive factors for weight loss of >5% from baseline. In order to validate our published findings, we similarly analysed a new consecutive cohort of 85 patients with the same inclusion criteria. The patient population was similar except for a higher incidence of N2/3 disease and slightly higher mean PTV volumes. The mean weight loss was 4.7% (range e14.95% to þ9.1%, standard deviation 5.0%). The incidence of weight loss of more than 5% was 29/85 patients (34.1%) and more than 10% in 14/85 patients (16.5%). A nasogastric tube was required in 35/85 patients (41.2%). We tested the PTV thresholds derived in the earlier report. Patients with a total PTV > 615 cm3 had significantly higher weight loss than those with a smaller PTV (6.0% versus 3.2%, P ¼ 0.009). Those with a prescription dose PTV > 235 cm3 also had more weight loss, although this did not reach statistical significance (5.3% versus 3.6%, P ¼ 0.1). Patients receiving CRT had significantly more weight loss than those receiving radiotherapy alone (6.0% versus 2.3%, P ¼ 0.001). We had proposed a simple risk stratification system to categorise patients based on these parameters. Using the same system in the validation cohort, we confirmed a significant difference in the incidence of weight loss >5% between risk groups (Table 1). The proportion of patients with a weight loss >5% in each group was also in alignment with the previous cohort.

Table 1 A simple risk stratification system Factors present

Weight loss >5%

Neither CRT nor large PTVs* Either CRT or large PTVs Both CRT and large PTVs P value

1/8 (12.5%) 14/33 (42.4%) 28/44 (63.6%) 0.014

CRT, chemoradiotherapy; PTV, planning target volume; prescPTV, prescription dose PTV. 3 * Large PTV defined as prescPTV > 235 cm or total PTV > 3 615 cm .

We believe that this simple system can be used in clinical practice to stratify patients for closer monitoring and timely nutritional interventions. S.K. Gupta*, I. Mallick*, R. Rayy, R.K. Shrimali*, R. Achari*, S. Chatterjee* * Department of Radiation Oncology, Tata Medical Center, Kolkata, India y Department of Clinical Nutrition, Tata Medical Center, Kolkata, India

Reference [1] Mallick I, Gupta SK, Ray R, et al. Predictors of weight loss during conformal radiotherapy for head and neck cancers d how important are planning target volumes? Clin Oncol 2013;25:557e563.

0936-6555/$36.00 Ó 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.clon.2014.05.008

Please cite this article in press as: Gupta SK, et al., Planning Target Volumes Determine Weight Loss in Highly Conformal Radiation Therapy in Head and Neck Cancers e A Validation Study, Clinical Oncology (2014), http://dx.doi.org/10.1016/j.clon.2014.05.008