Radiotherapy for solitary extramedullary plasmacytoma in the head-and-neck region: A dose greater than 45 Gy to the target volume improves the local control

Purpose: Our aim was to determine the dose to the clinical target volume (CTV) required for solitary extramedullary plasmacytoma (EMP) in the head and neck (HN).

Methods and Materials: Seventeen patients (15 Stage I and 2 Stage II) were treated for HN EMP at our institution between 1979 and 2003. The mean International Commission on Radiation Units (ICRU) dose prescribed to the CTV was 52.6 Gy (range, 40–65 Gy) over 24 fractions (range: 20–30). The Stage II patients received neck irradiation doses of 40 and 60 Gy. A mean dose of 36.4 Gy was used for 5 Stage I patients who received elective neck irradiation. Dose administrated to the CTV was evaluated from dosimetric data or from planning films when dosimetric data were not available. Two groups of patients were distinguished: CTV covered with a dose greater than 40 Gy and CTV covered with a dose greater than 45 Gy.

Results: The 5-year local control was 72.8%. It was 100% for patients who received dose to the CTV ≤ 45 Gy vs. 50% for dose to the CTV <45 Gy (p = 0.034). The prognostic factor for 5-year disease-specific survival (81.6%) was local control (p = 0.058). The prognostic factors for disease-free survival (64.1%) were monoclonal immunoglobulin secretion (p = 0.008) and a CTV dose ≤ 45 Gy (p = 0.056)

Conclusions: Local control of EMP in the HN seems to be improved when the dose to the CTV is ≤ 45 Gy. A minimum dose of 45 Gy should be recommended to the CTV.

Keywords:  Extramedullary plasmacytoma , Head and neck , Radiation therapy , Treatment