Impact of tumor attachment to the pleura measured by a pretreatment CT image on outcome of stage I NSCLC treated with stereotactic body radiotherapy

Takaya Yamamoto, Noriyuki Kadoya, Yuko Shirata, Masashi Koto, Kiyokazu Sato, Haruo Matsushita, Toshiyuki Sugawara, Rei Umezawa, Masaki Kubozono, Yojiro Ishikawa, Maiko Kozumi, Noriyoshi Takahashi, Kengo Ito, Yu Katagiri, Ken Takeda, Keiichi Jingu

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10 Citations (Scopus)

Abstract

Background: Pleural invasion status is known to be a predictor of survival after pulmonary resection for non-small cell lung cancer. Our goal was to determine whether the length of tumor attachment to the pleura on a pretreatment CT image has prognostic value as an alternative to pleural invasion status for stage I non-small cell lung cancer treated with stereotactic body radiotherapy (SBRT). Methods: A total of 90 tumors in 87 patients (males: 68, females: 19) who received SBRT between March 2005 and September 2011 in our institution were reviewed. The median age of the patients was 78 years (range, 48-90 years). The median tumor diameter was 2.2 cm (range, 0.9-4.2 cm). The prescribed dose was typically 48 Gy in 4 fractions, 60 Gy in 8 fractions or 60 Gy in 15 fractions to the isocenter with 6 MV X-ray using 4 non-coplanar and 3 coplanar static beams. The lengths of attachment were measured using pretreatment CT images at the lung window. Cumulative incidence rates were calculated using Kaplan-Meier curves, and univariate and multivariate analyses for in-field tumor control, locoregional control (LRC), freedom from distant metastasis and freedom from progression (FFP) were performed using a Cox proportional hazards model. Results: Of the 90 tumors, 42 tumors were attached to the pleura (median, 14.7 mm; range, 4.3-36.0 mm), 21 tumors had pleural indentation and 27 tumors had no attachment. The median follow-up period for survivors was 46.1 months. The 3-year in-field control, LRC, FFP and overall survival rates were 91.2%, 75.3%, 63.8% and 68.6%, respectively. SBRT dose and tumor diameter were independently significant predictors of in-field control (p = 0.02 and p = 0.04, respectively). Broad attachment to the pleura, the length being more than 14.7 mm, was a negative independent predictor of LRC and FFP (p = 0.02 and p = 0.01, respectively). Conclusions: Pleural attachment status on a pretreatment CT image might be an important predictor of LRC and FFP.

Original languageEnglish
Article number35
JournalRadiation Oncology
Volume10
Issue number1
DOIs
Publication statusPublished - 2015 Feb 7

Keywords

  • Lung cancer
  • Pleural attachment
  • Pleural contact
  • Pleural invasion
  • Prognostic factor
  • Stereotactic radiotherapy

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging

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