Lung dose-volume parameters and the risk of pneumonitis for patients treated with accelerated partial-breast irradiation using three-dimensional conformal radiotherapy.

PURPOSE: There are no data on how complication rates after accelerated partial-breast irradiation delivered by three-dimensional conformal radiotherapy are affected by treatment technique. We therefore examined the risk of pneumonitis in relation to lung dose-volume parameters. PATIENTS AND METHODS: Our prospective dose-escalation trial enrolled 198 treated patients from 2003 to 2007. Patients received 32 or 36 Gy in 4-Gy fractions, given twice daily: 29 (14%) were treated with pure photons; 149 (77%) with mixed photons and electrons; and 20 (10%) with protons. RESULTS: There were four cases of pneumonitis at 4, 4, 7, and 9 months after treatment. All were in the 36-Gy cohort and were treated with pure photons. The risk of pneumonitis for the two cohorts combined was: 17% (four of 24) for an ipsilateral lung volume (ILV) receiving 20 Gy or higher (ILV, 20 Gy) of 3% or higher (P = .0002 for comparison to ILV 20 Gy < 3%, Fisher's exact test); 20% (four of 20) for an ILV 10 Gy of 10% or higher (P = .0001); and 15% (four of 26) for an ILV 5 Gy of 20% or higher (P = .0002). CONCLUSION: The risk of pneumonitis appeared related to the ILV treated. This volume can be reduced by using mixed photons and electron when possible. We recommend that the ILV 20 Gy should be lower than 3%, the ILV 10 Gy lower than 10%, and the ILV 5 Gy lower than 20% when purely coplanar techniques are used.

A prospective study of salivary gland function in lymphoma patients receiving head and neck irradiation.

PURPOSE: To determine the radiation dose-response relationship on salivary dysfunction and quality of life (QOL) over time in patients with lymphoma receiving radiation therapy (RT) to the head and neck (H&N). METHODS AND MATERIALS: We conducted a prospective study on salivary-gland function in lymphoma patients receiving RT to the H&N. Fifteen patients were enrolled on the study. Dose-volume histograms and mean doses to the salivary glands were generated. Radiation-related toxicities and H&N-specific QOL were assessed before treatment and at prespecified time points posttreatment. Factors predicting a decrement in QOL were explored using Fisher's exact test. RESULTS: During RT, 47% of patients experienced Grade >or= 2 acute toxicity of the salivary gland, mucous membrane, or both. QOL scores improved over time, but up to one third of patients continued to have persistent oral symptoms at 2 years. At 6 months, a mean dose to at least one of the parotids of > 31 Gy was significantly associated with persistent dry mouth (100% vs. 17%, p = 0.02) and sticky saliva (100% vs. 25%, p = 0.04); a mean dose of > 11 Gy to the minor salivary glands was significantly associated with persistent sticky saliva (100% vs. 25%, p = 0.04), although the difference was no longer significant at 1 year. CONCLUSIONS: Limiting the mean parotid dose to