Novel 10-fraction Breast Irradiation in Prone and Supine Position: Technical, Dosimetric and Clinical Evaluation

Characterization of Respiration-Induced Motion in Prone Versus Supine Patient Positioning for Thoracic Radiation Therapy

Purpose

Variations in the breathing characteristics, both on short term (intrafraction) and long term (interfraction) time scales, may adversely affect the radiation therapy process at all stages when treating lung tumors. Prone position has been shown to improve consistency (ie, reduced intrafraction variability) and reproducibility (ie, reduced interfraction variability) of the respiratory pattern with respect to breathing amplitude and period as a result of natural abdominal compression, with no active involvement required from the patient. The next natural step in investigating breathing-induced changes is to evaluate motion amplitude changes between prone and supine targets or organs at risk, which is the purpose of the present study.

Methods and Materials

Patients with lung cancer received repeat helical 4-dimensional computed tomography scans, one prone and one supine, during the same radiation therapy simulation session. In the maximum-inhale and maximum-exhale phases, all thoracic structures were delineated by an expert radiation oncologist. Geometric centroid trajectories of delineated structures were compared between patient orientations. Motion amplitude was measured as the magnitude of difference in structure centroid position between inhale and exhale.

Results

Amplitude of organ motion was larger when the patient was in the prone position compared with supine for all structures except the lower left lobe and left lung as a whole. Across all 12 patients, significant differences in mean motion amplitude between orientations were identified for the right lung (3.0 mm, P = .01), T2 (0.5 mm, P = .01) and T12 (2.1 mm, P < .001) vertebrae, the middle third of the esophagus (4.0 mm, P = .03), and the lung tumor (1.7 mm, P = .02).

Conclusions

Respiration-induced thoracic organ motion was quantified in the prone position and compared with that of the supine position for 12 patients with thoracic lesions. The prone position induced larger organ motion compared with supine, particularly for the lung tumor, likely requiring increases in planning margins compared with supine.

Hypofractionated Radiation Therapy for Breast Cancer: Long-Term Results in a Series of 85 Patients

Purpose

Whole-breast irradiation after conservative surgery is the standard treatment for early breast cancer. The purpose of this study is to report the late toxicity, cosmetic result, and disease control in a group of patients treated with hypofractionated radiotherapy (RT) comparing results with retrospective data of a control group who underwent conventional RT.

Methods

From 2006 to 2008, 85 patients were treated with hypofractionated schedule to dose of 45 Gy, 2.25 Gy/fr, followed by a boost. We evaluated late toxicity, cosmetic result, and disease control. The data were compared to a control group of 70 patients who underwent conventional RT before 2006.

Results

At 8 years of follow-up, the cumulative incidence of late skin toxicity was 6.2 in the hypofractionated RT group and 7.5 in the standard RT group (p = 0.94). The cumulative incidence of late subcutaneous tissue toxicity was 11.6 in the hypofractionated RT group and 18.7 in the standard RT group (p = 0.23). Cosmetic outcome was rated as excellent or good in 84/85 patients of the hypofractionated RT group and in 68/70 patients of the conventional RT group (p = 0.7). No statistically significant differences were found in terms of local control (p = 0.05), disease-free survival (p = 0.06), or overall survival (p = 0.17) between the 2 groups.

Conclusions

The present analysis, focused on long-term effects, disease control, and survival, confirms, in a daily practice setting, the low incidence of skin atrophy and fibrosis, the satisfactory cosmetic outcome, and the high grade of local and distant disease control with hypofractionated schedule.

Hypofractionated irradiation of infra-supraclavicular lymph nodes after axillary dissection in patients with breast cancer post-conservative surgery: impact on late toxicity

Background

The aim of the present work was to analyse the impact of mild hypofractionated radiotherapy (RT) of infra-supraclavicular lymph nodes after axillary dissection on late toxicity.

Methods

From 2007 to 2012, 100 females affected by breast cancer (pT1- T4, pN1-3, pMx) were treated with conservative surgery, Axillary Node Dissection (AND) and loco-regional radiotherapy (whole breast plus infra-supraclavicular fossa). Axillary lymph nodes metastases were confirmed in all women. The median age at diagnosis was 60 years (range 34–83). Tumors were classified according to molecular characteristics: luminal-A 59 pts (59 %), luminal-B 24 pts (24 %), basal-like 10 pts (10 %), Her-2 like 7 pts (7 %). 82 pts (82 %) received hormonal therapy, 9 pts (9 %) neo-adjuvant chemotherapy, 81pts (81 %) adjuvant chemotherapy. All patients received a mild hypofractionated RT: 46 Gy in 20 fractions 4 times a week to whole breast and infra-supraclavicular fossa plus an additional weekly dose of 1,2 Gy to the lumpectomy area. The disease control and treatment related toxicity were analysed in follow-up visits. The extent of lymphedema was analysed by experts in Oncological Rehabilitation.

Results

Within a median follow-up of 50 months (range 19–82), 6 (6 %) pts died, 1 pt (1 %) had local progression disease, 2 pts (2 %) developed distant metastasis and 1 subject (1 %) presented both. In all patients the acute toxicity was mainly represented by erythema and patchy moist desquamation. At the end of radiotherapy 27 pts (27 %) presented lymphedema, but only 10 cases (10 %) seemed to be correlated to radiotherapy. None of the patients showed a severe damage to the brachial plexus, and the described cases of paresthesias could not definitely be attributed to RT. We did not observe symptomatic pneumonitis.

Conclusions

Irradiation of infra-supraclavicular nodes with a mild hypofractionated schedule can be a safe and effective treatment without evidence of a significant increase of lymphedema appearance radiotherapy related.