Exploring the Relationship of Radiation Dose Exposed to the Length of Esophagus and Weight Loss in Patients with Lung Cancer.

PURPOSE

We investigate whether esophageal dose-length parameters (L) can robustly predict significant weight loss-≥5% weight loss during radiation therapy (RT) compared with the weight before RT-in patients with lung cancer treated with definitive intent.

METHODS AND MATERIALS

Patients with lung cancer treated with conventionally fractionated RT between 2010 and 2018 were retrospectively identified. L and L, the length of full- and partial-circumferential esophagus receiving greater than a threshold dose in Gy, respectively, were created. Multivariate logistic regression examined the associations between individual L and weight loss after adjusting for clinical parameters and correcting for multiple comparisons. Ridge logistic regression examined the relative importance of L compared with dose-volume (V), mean dose (D), and clinical parameters in determining weight loss. Univariate logistic regression examined the unadjusted probability of weight loss for important L parameters.

RESULTS

Among the 214 patients identified, median age was 66.9 years (range, 31.5-88.9 years), 50.5% (n = 108) were male, 68.2% (n = 146) had stage III lung cancer, median RT dose was 63 Gy (range, 60-66 Gy), and 88.3% (n = 189) received concurrent chemotherapy. Esophagus lengths receiving high full-circumferential (L-L) and high partial-circumferential doses (L) were associated with significant weight loss (P ≤ .05). L and L reached near significance (P = .06 and .053, respectively). L > L > L were the most important dose parameters in determining weight loss compared with other L, V, and D parameters.

CONCLUSIONS

Esophageal L parameters are an efficient way of interpreting complex dose parameters in relation to weight loss toxicity among patients with lung cancer receiving definitive RT.