Author of

• 12544

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  P3.08 - Poster Session 3 - Radiotherapy (ID 199)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Radiation Oncology + Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12559

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    P3.08-015 - Dosimetric factors associated with weight loss during radiotherapy treatment for non-small cell lung cancer (ID 2033)

    09:30 - 09:30  |  Author(s): M. Krishnasamy
    • Abstract

    Background
    Thoracic radiotherapy is associated with significant acute toxicities including oesophagitis, anorexia and fatigue which can impact on the ability to achieve adequate nutritional intake, subsequently leading to weight loss and malnutrition. Malnutrition during cancer treatment is associated with poorer patient and treatment outcomes. Understanding factors associated with weight loss assists with the early identification and intervention of patients at nutritional risk. This study aimed to identify radiotherapy dosimetric factors associated with clinically significant weight loss (greater than or equal to 5%) in patients receiving treatment for non-small cell lung cancer (NSCLC).

    Methods
    A retrospective analysis of an existing cohort of 54 NSCLC patients treated with concurrent chemoradiotherapy for whom oesophageal dose distributions had previously been calculated. Weight change was calculated at any time point from the start up to 90 days from radiotherapy commencement to determine those with clinically significant weight loss. Chi-squared tests, Pearson correlation, Mann-Whitney U-test and logistic regression were used to examine associations.

    Results
    Four patients for whom weight was not available at the start or end of treatment were excluded leaving 50 patients for analysis. The prevalence of clinically significant weight loss was 22% (median weight loss 9.1%, range 5.9 – 22.1). Dosimetric factors associated with clinically significant weight loss were maximum dose to the oesophagus (z= -1.99, p=.046), absolute oesophageal length receiving 40Gy (r=.32, p=.03), 50Gy (r=.36, p=.01) and 60Gy (r=.45, p=.001) to the partial circumference, relative oesophageal length receiving 50Gy (r=.32, p=.02) and 60Gy(r=.44, p=.001) to the partial circumference. The odds of a patient receiving 40Gy (median length 10.6cm), 50Gy (median length 10.2cm) or 60Gy (median length 7.2cm) to the partial oesophagus experiencing clinically significant weight loss were 1.18 (95%CI 1.01,1.37, p=.04), 1.20 (95%CI 1.03,1.41, p=.02) and 1.32 (95%CI 1.09,1.60, p=.005) greater, respectively, than those with less oesophagus in the treatment field. Nine (82%) of the eleven patients who had clinically significant weight loss received a dose of 60Gy to at least 5cm of the partial circumference of the oesophagus.

    Conclusion
    The strongest dosimetric association with clinically significant weight loss was absolute oesophageal length receiving 60Gy to the partial circumference. A previous study identified an association between concurrent chemotherapy and late stage disease (stage III or IV) and clinically significant weight loss. Findings from both studies have been used to develop a model, currently undergoing validation, to assist clinicians in predicting NSCLC radiotherapy patients at high nutritional risk.