Computed Tomographic Evaluation of Posttreatment Soft-Tissue Changes by Using a Lymphedema Scoring System in Patients with Oral Cancer

Masaya Akashi, Shun Teraoka, Yasumasa Kakei, Junya Kusumoto, Takumi Hasegawa, Tsutomu Minamikawa, Kazunobu Hashikawa, and Takahide Komori. LYMPHATIC RESEARCH AND BIOLOGY Volume 00, Number 00, 2017

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Computed Tomographic Evaluation of Posttreatment Soft-Tissue Changes by Using a Lymphedema Scoring System in Patients with Oral Cancer

Masaya Akashi, Shun Teraoka, Yasumasa Kakei, Junya Kusumoto, Takumi Hasegawa, Tsutomu Minamikawa, Kazunobu Hashikawa, and Takahide Komori. LYMPHATIC RESEARCH AND BIOLOGY Volume 00, Number 00, 2017

Background: This study aimed to evaluate posttreatment soft-tissue changes in patients with oral cancer with computed tomography (CT). To accomplish that purpose, a scoring system was established, referring to the criteria of lower leg lymphedema (LE).

Methods and Results: One hundred and six necks in 95 patients who underwent oral oncologic surgery with neck dissection (ND) were analyzed retrospectively using routine follow-up CT images. A two-point scoring system to evaluate soft-tissue changes (so-called ‘‘LE score’’) was established as follows: Necks with a ‘‘honeycombing’’ appearance were assigned 1 point. Necks with ‘‘taller than wide’’ fat lobules were assigned 1 point. Necks with neither appearance were assigned 0 points. Comparisons between patients with LE score ‡1 and LE score=0 at 6 months postoperatively were performed using the Fisher exact test for discrete variables and the Mann–Whitney U test for continuous variables. Univariate predictors associated with posttreatment changes (i.e.,LEscore‡1at6monthspostoperatively)wereenteredintoamultivariatelogisticregressionanalysis.Values of p<0.05 were considered to indicate statistical significance. The occurrence of the posttreatment soft-tissue changes was 32%. Multivariate logistic regression analysis showed that postoperative radiation therapy (RT) and bilateral ND were potential risk factors of posttreatment soft-tissue changes on CT images.

Conclusions: Sequential evaluation of ‘‘honeycombing’’ and the ‘‘taller than wide’’ appearances on routine follow-up CT revealed the persistence of posttreatment soft-tissue changes in patients who underwent oral cancer treatment, and those potential risk factors were postoperative RT and bilateral ND.

Main findings

  • Two independent clinicians assessed the CT images in consensus. The evaluated the same CT features (e.g., ‘‘honeycombing appearance’’ and ‘‘taller than wide’’ appearances of the fat lobules).
  • Necks in which the ‘‘honeycombing’’ appearance was observed on CT images were assigned 1 point. Necks in which the ‘‘taller than wide’’ fat lobules were observed on CT images were assigned 1 point.
  • This study showed that the scoring system using CT could reflect the state of posttreatment soft-tissue changes on the basis of the potential risk factors (postoperative RT and bilateral ND). In oral cancer patients, the percentage of posttreatment changes (i.e., LE score ‡1) at 6 months postoperatively was only 32%, and none of patients without the potential risk factors had posttreatment changes on CT images at 18 months postoperatively.
  • The two-point scoring system used in this study is useful for identifying post therapeutic tissue changes that are probably due to inflammation, fibrosis, and external LE. Sequential evaluation of ‘‘honeycombing’’ and the ‘‘taller than wide’’ appearances on routine follow-up CT showed that the incidence of posttreatment soft-tissue changes was 32% in patients who underwent oral cancer treatment, and those potential risk factors were postoperative RT and bilateral ND.
  • Further study is needed to analyze the relation between patients’ symptoms and the abnormal CT findings (‘‘honeycombing’’ and ‘‘taller than wide’’ appearances).