Nasal cavity reirradiation: a challenging case for comparison between proton therapy and volumetric modulated arc therapy.

BACKGROUND

The aim of this case report is to report on a dosimetric comparison between volumetric modulated arc therapy (RapidArc technique and active scanning proton therapy (single-field (SFO) and multifield (MFO) techniques) in a case of nasal cavity cancer recurrence.

CASE REPORT: A 72-year-old man, who received adjuvant radiotherapy for a carcinoma of the nasal cavity, experienced an unresectable local recurrence in the previous surgical bed. Hence, the patient was evaluated for reirradiation by comparing different modalities, with a total prescribed dose of 50 Gy in standard fractionation. RA plan was revealed to be equivalent to the MFO plan in terms of target dose coverage and conformity index. SFO plan was not able to respect a maximum dose of 9 Gy to nervous structures, in contrast to RA and MFO plans.

CONCLUSIONS

In this challenging scenario, although a clear preference would be given to the MFO proton plan, the RA plan was revealed to be adequate for the clinical goal of target coverage and sparing of organs at risk.