A Systematic Review of Phase II/III Trials of Hypofractionated versus Conventionally Fractionated Radiation Therapy...

This systematic review evaluated whether curative intent hypofractionated radiation therapy improved survival (primary endpoint) as compared to standard conventionally fractionated radiation therapy for stage III non-small cell lung cancer (NSCLC) patients. Toxicity was also examined as a secondary endpoint.

Electronic bibliographic databases were searched from 1 January 1990 to 31 March 2024. Phase II and phase III trials were included to assess survival (primary outcome) and toxicity (secondary outcome) for newly diagnosed stage III NSCLC patients.

Eight phase II trials (n = 349 participants), 3 randomized phase II trials (n = 382 participants), and 5 randomized phase III trials (n = 811 participants), for a total of 1542 participants, were identified. The published trials were heterogeneous, with a wide variety of dose prescriptions. A wide range of survivals (median survival 13.6 months-42.5 months) and toxicities such as grade 3 or higher esophagitis (0-42%) and grade 3 or higher pneumonitis (0-18%) were reported.

There is no level 1 evidence to date that suggests that any hypofractionated regimen (dose escalated or not) improves survival as compared to conventionally fractionated radiation. The published phase III trials have been powered for superiority (not equivalence) for the hypofractionated arm. Toxicity with hypofractionated regimens may be similar to conventionally fractionated regimens when normal tissue radiotherapy constraints are kept within tolerance limits. It is unclear how the use of systemic therapy may negatively affect radiation toxicity with hypofractionated radiation therapy.