Patient population

Medical and radiotherapy planning records of consecutive patients with NSCLC (July 2013–December 2017) treated with curative intent radiotherapy at a tertiary cancer center were retrieved. Treatment plans of 202 patients, of whom 93 had required IMRT, were analyzed. The final treatment plan for these patients had been evaluated and approved using standard planning criteria which are presented in Table 1.^9–12 Eclipse treatment planning system (v. 10.0.42 till September 2017, and v. 15.1.52.01 subsequently, Varian Medical Systems, Palo Alto, CA) was used to generate all the plans. The authors have described the typical planning process used for generating complex 3DCRT and for IMRT (including volumetric arc therapy) plans for lung cancers in an earlier publication.¹³ For all cases, the treatment plan evaluation and approval were done by senior medical physicists and senior clinical oncologists with more than 10 years of experience. Until mid-2014, for all patients, the planning process started with the development of a 3DCRT plan. If the planners failed to create a 3DCRT plan that achieved all of the objective criteria, they would attempt complex multifield and multisegment 3DCRT, before deciding on changing to an IMRT plan. As can be expected, for several cases, significant time would have been spent in iterating a 3DCRT plan before the decision for planning IMRT would be taken. Subsequently, as the team gained more experience senior physicists estimated whether IMRT was needed upfront.

Institutional plan evaluation criteria

PTV, planning target volume.