Masahide Saito, Keiichi Jingu, Naoki Tohyama, Hikaru Nemoto, Takayuki Kanai, Masahiko Kurooka, Seiichi Ota, Rei Umezawa, Yoshiyuki Katsuta, Kazuya Takeda, Masaki Matsuda, Tetsuro Tamamoto, Ryoji Shinohara, Akihisa Wakita, Hiroshi Onishi
Under these benchmark study conditions, target delineation accuracy and plan quality under a single full-time radiation oncologist supported by structured remote/part-time peer review and mandatory planning assistance were comparable to Japan's two-oncologist standard, supporting the feasibility of this structured model for widening IMRT access.
PURPOSE: To determine whether intensity-modulated radiation therapy (IMRT) plan quality under a proposed facility standard of one full-time radiation oncologist supported by structured remote or part-time peer review and mandatory planning assistance is comparable to Japan's current standard requiring two full-time radiation oncologists.
MATERIALS AND METHODS: In this multicenter, pair-matched, prospective trial, 41 institutional pairs were enrolled and 36 completed per protocol. Within each pair, one institution had two full-time radiation oncologists (Group A) and the other had one full-time radiation oncologist (Group B), with mandated remote or part-time peer review and planning-assistant involvement at the single-oncologist site. Common cases (prostate cancer; nasopharyngeal carcinoma [NPC] with whole-neck [WNI] or local boost [LBI] irradiation) and consensus reference contours were provided. Primary endpoints were target delineation accuracy versus the reference contour (dice similarity coefficient, DSC) and plan quality (plan quality metric, PQM; 0-100).
RESULTS: Differences in DSC (Group B - A) were 0.00 (95% CI - 0.02 to 0.02) for prostate cancer, - 0.02 (- 0.06 to 0.02) for NPC-WNI, and - 0.04 (- 0.09 to 0.02) for NPC-LBI. PQM differences were 2.01 (- 2.05 to 6.07), - 3.51 (- 8.65 to 1.62), and - 2.52 (- 6.52 to 1.49), respectively. All differences fell within the pre-specified comparability margins, with no significant between-group differences.
CONCLUSION: Under these benchmark study conditions, target delineation accuracy and plan quality under a single full-time radiation oncologist supported by structured remote/part-time peer review and mandatory planning assistance were comparable to Japan's two-oncologist standard, supporting the feasibility of this structured model for widening IMRT access.