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Dosimetric differences between local failure and local controlled non‐small cell lung cancer patients treated with stereotactic body radiotherapy: A matched‐pair study
Author(s) -
Zhuang Tingliang,
Woody Neil M,
Liu Han,
Cherian Sheen,
Reddy Chandana A,
Qi Peng,
Magnelli Anthony,
Djemil Toufik,
Stephans Kevin L,
Xia Ping,
Videtic Gregory MM
Publication year - 2018
Publication title -
journal of medical imaging and radiation oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 43
eISSN - 1754-9485
pISSN - 1754-9477
DOI - 10.1111/1754-9485.12706
Subject(s) - medicine , nuclear medicine , lung cancer , radiation therapy , radiation treatment planning , radiology
Abstract Introduction Concerns were raised about the accuracy of pencil beam ( PB ) calculation and potential underdosing of medically inoperable non‐small cell lung cancer ( NSCLC ) treated with stereotactic body radiation therapy ( SBRT ). From our institutional series, we designed a matched‐pair study where each local failure and controlled patient was matched based upon several clinical factors, to investigate the dose difference between the matched‐pair. Methods Eighteen pairs of NSCLC patients, treated with 50 Gy in five fractions, were selected. These patients were matched based on treatment intent, tumour size, histology and clinical follow‐up. All PB calculated clinical plans were retrospectively recalculated with a MC algorithm. The D 99 and D M ean of the gross tumour volume ( GTV ) and D 95 and D M ean of the planning tumour volume ( PTV ) from PB and Monte Carlo ( MC ) calculation were compared between local failures and controls using the Mann–Whitney test. Results The mean PB calculated D95 of PTV was 50.4 Gy for both failures and controls ( P = 0.85), indicating no planning differences between the groups. From MC calculations, the mean (±SD) of GTV D 99 , GTV D M ean , PTV D 95 , PTV D M ean were 47.6 ± 2.6/46.3 ± 2.4, 50.4 ± 2.1/49.8 ± 1.6, 44.4 ± 2.7/43.6 ± 3.1, 48.7 ± 2.4/48.2 ± 2.4 Gy for failure/controlled groups, respectively, and there was no significant difference between two groups (all P > 0.1). The dose differences between MC and PB calculations were in agreement with other literatures and there was no significant difference between two groups. Conclusions While PB algorithms may overestimate tumour doses relative to MC algorithms, our matched‐pair study did not find dose differences between local failure and local controlled cases.