Adaptive time management for patients who have non-small cell lung cancer and underwent definitive radiotherapy: a dosimetric study of different gap duration scenarios

Abstract

Purpose

The purpose of this study was to evaluate the tumor control probability (TCP), normal tissue complication probability (NTCP) and adaptive time management (ATM) in patients who had non-small cell lung cancer (NSCLC) and underwent radiotherapy with same gap length at different treatment weeks.

Material and Methods

Twenty patients’ definitive radiotherapy treatments, completed in 6.5 weeks, were evaluated retrospectively. Three different scenarios with gaps in 5 fractions at different weeks of treatment (2nd, 4th, and 6th week) were planned. Three ATM models (biologically effective dose (C_BED), time-dose-fractionation (C_TDF) and in-house developed (C_InH)) were calculated for each scenario. TCP and NTCP were calculated and compared with the dose-volume histogram (DVH) of each model.

Results

TCP was accepted as 100% in uninterrupted treatments. When treatment was interrupted and not compensated with ATM, the highest TCP difference was determined as 23.46% in the 4th week (p<.001). Based on comparisons of ATM models, the lowest TCP decrease was found in C_InH. Increasing the fraction size by C_InH and C_BED provided more TCP improvement than increasing the number of fractions by C_TDF.

Conclusion

The treatment gap to be given in the middle of the treatment is more challenging in terms of tumor control. Adaptive approaches that maintain overall treatment time while increasing fractional dose offer increased TCP.

Keywords:

• Adaptive time management
• treatment interruption
• non-small cell lung cancer
• radiotherapy

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Aysun Inal

Aysun Inal (PhD) is a Senior Medical Physicist of University of Health Sciences Antalya Training and Research Hospital, Department of Radiation Oncology, Antalya and a Health Physicist at ATL health and imaging services company, Ankara

Evrim Duman

Evrim Duman (MD) is a Radiation Oncologist of University of Health Sciences Antalya Training and Research Hospital, Department of Radiation Oncology, Antalya