Three-dimensional conformal breast irradiation in the prone position

Prone Breast Radiotherapy in a Patient with Early Stage Breast Cancer and a Large Pendulous Breast

In women with large and pendulous breasts postoperative radiotherapy in the supine position could represent a technical challenge because of the resulting dose inhomogeneity and the large amount of lung and heart receiving a high percentage of the prescribed dose. Breast-conserving surgery is therefore relatively contraindicated in these patients. Alternative positions for radiation therapy treatment have been proposed, and prone breast irradiation in particular has been recognized as a useful alternative to conventional treatment in the supine position. We report the case of a large-breasted patient treated in prone position in our radiation therapy division.

Prospective study of postoperative whole breast radiotherapy for Japanese large-breasted women: a clinical and dosimetric comparisons between supine and prone positions and a dose measurement using a breast phantom

BACKGROUND

This prospective study aimed to compare dose volume histograms (DVH) of the breasts and organs at risk (OARs) of whole breast radiotherapy in the supine and prone positions, and frequency and severity of acute and late toxicities were analyzed.

METHODS

Early-stage breast cancer patients with large breasts (Japanese bra size C or larger, or the widest measurements of the bust ≥ 95 cm) undergoing partial mastectomy participated in this study. CT-based treatment plans were made in each position, and various dosimetric parameters for the breast and OARs were calculated to compare the supine and prone radiotherapy plans. The actual treatment was delivered in the position regarded as better.

RESULTS

From 2009 to 2010, 22 patients were prospectively accrued. Median follow-up period was 58 months. The homogeneity index and lung doses were significantly lower in the prone position (P = 0.008, P < 0.0001 and P < 0.0001, respectively). Cardiac dose showed no significant differences between two positions. By comparing two plans, the prone position was chosen in 77 % of the patients. In the prone position, ≥ grade 2 acute dermatitis were seen in 47 % of patients treated, whereas 20 % of the patients treated in the supine position had grade 2 and no cases of grade 3, although without a statistical significance of the rates of ≥ grade 2 acute dermatitis between the two positions (P = 0.28). The actual dose measurement using a breast phantom revealed significantly higher surface dose of the breast treated in the prone position than that in the supine position.

CONCLUSIONS

Breast irradiation in the prone position improves PTV homogeneity and lowers doses to the OARs in the Japanese large-breast patients. However meticulous positioning of the breast in the prone board avoiding the bolus effect is necessary to prevent acute dermatitis.

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

Background

The aim of this study was to evaluate retrospectively the planned dose distribution and acute toxicity of adjuvant hypofractionated whole breast radiotherapy (RT) delivered in the prone vs. supine position.

Methods

Twenty-four patients were enrolled; 12 underwent adjuvant RT with a supine setup and 12 with a prone setup. We included patients according to breast volume (≥500 mL), disease stage (≤pT2/pN1), and clinical/biological features. Patients received a regimen of 35 Gy in 10 fractions for 2.5 weeks, and a concomitant boost of 3/4 Gy in 1 fraction/week. Target coverage was assessed by volume, V90, V95, V100, V103 and V105. Heart, LADCA and ipsilateral lung doses were evaluated according to volume, maximum dose, mean dose, V14, V10 and V5. We evaluated acute skin toxicity during RT, at the end of treatment, and after 1 month according to RTOG scales.

Results

Radiobiological equivalence was warranted with satisfactory BED values: considering α/β = 4 for breast cancer, the 10-fraction schedule equaled 74 or 77 Gy depending on the boost dose (3 Gy vs. 4 Gy, respectively). Toxicity was low and similar for supine and prone treatments. Dose sparing was significant in the ipsilateral lung in the prone position (median Dmax: 28.7 Gy vs. 38.4 Gy; median Dmean: 0.8 Gy vs. 6.3 Gy; median V14:0.6% vs. 13.5%; median V5: 0 vs. 19.3%, p<0.001).

Conclusions

This novel 10-fraction schedule is feasible and well tolerated; the prone position allows better saving of OARs, with a statistically significant value for the ipsilateral lung.

Cardiac dose sparing and avoidance techniques in breast cancer radiotherapy

Breast cancer radiotherapy represents an essential component in the overall management of both early stage and locally advanced breast cancer. As the number of breast cancer survivors has increased, chronic sequelae of breast cancer radiotherapy become more important. While recently published data suggest a potential for an increase in cardiac events with radiotherapy, these studies do not consider the impact of newer radiotherapy techniques commonly utilized. Therefore, the purpose of this review is to evaluate cardiac dose sparing techniques in breast cancer radiotherapy. Current options for cardiac protection/avoidance include (1) maneuvers that displace the heart from the field such as coordinating the breathing cycle or through prone patient positioning, (2) technological advances such as intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT), and (3) techniques that treat a smaller volume around the lumpectomy cavity such as accelerated partial breast irradiation (APBI), or intraoperative radiotherapy (IORT). While these techniques have shown promise dosimetrically, limited data on late cardiac events exist due to the difficulties of long-term follow up. Future studies are required to validate the efficacy of cardiac dose sparing techniques and may use surrogates for cardiac events such as biomarkers or perfusion imaging.

A phase I/II study piloting accelerated partial breast irradiation using CT-guided intensity modulated radiation therapy in the prone position

BACKGROUND AND PURPOSE

External beam accelerated partial breast irradiation (EB-aPBI) is noninvasive with broader potential applicability than aPBI using brachytherapy. However, it has inherent challenges in daily reproducibility. Image-guide radiotherapy (IGRT) can improve daily reproducibility, allowing smaller treatment margins. Our institution proposed IG-IMRT in the prone position to evaluate dose homogeneity, conformality, normal tissue avoidance, and reliable targeting for EB-aPBI. We report preliminary results and toxicity from a phase I/II study evaluating the feasibility of EB-aPBI in the prone position using IG-IMRT.

MATERIALS AND METHODS

Twenty post-menopausal women with node-negative breast cancer, excised tumors <3.0 cm, negative sentinel lymph node biopsy, and surgical clips demarcating the lumpectomy cavity underwent prone EB-aPBI using IG-IMRT on an IRB-approved phase I/II study. All patients underwent CT planning in the prone position. The lumpectomy cavity PTV represented a 2.0 cm expansion. 38.5 Gy was delivered in 10 fractions over 5 days, such that 95% of the prescribed dose covered >99% of the PTV. Dose constraints for the whole breast, lungs and heart were met.

RESULTS

The median patient age was 61.5. Mean tumor size was 1.0 cm. 35% of patients had DCIS. Median PTV was 243 cc (108-530) and median breast reference volume was 1698 cc (647-3627). Average daily shifts for IGRT were (0.6, -4.6, 1.7 mm) with standard deviations of (6.3, 6.5, 6.4mm). Acute toxicity was G1 erythema in 80%, and G2 erythema, G2 fatigue, and G2 breast pain each occurred in 1 patient. With a median follow-up of 18.9 months (12-35), 40% of patients have G1 fibrosis and 30% have G1 hyperpigmentation. 95% of patients have good to excellent cosmesis. There have been no recurrences.

CONCLUSIONS

These data demonstrate that EB-aPBI in the prone position using IG-IMRT is well tolerated, yields good dosimetric conformality, and results in promising early toxicity profiles.

Virtual navigator 3D panoramic for breast examination

Breast examination both for screening and second level of investigation has spread worldwide, due to increased breast cancer awareness. Thus, different diagnostic imaging technologies emerged in breast application. Ultrasound (US), a real-time examination, non-invasive, cost effective, ideal also for repetitive follow-up and able to give information about anatomy, hemodynamics and tissue stiffness, plays an important role in breast diagnostics. The present work describes the innovative three-dimensional (3D) Panoramic (Pan) tool of Virtual Navigator technology for real-time fusion imaging of breast 3D US volumes with bi-dimensional US scans. A Motion Control Sensor enables the correction of the examined subject's movements. Data about fusion precision and system performances will be presented regarding tests in vitro, in ex-vivo and in vivo.

Prone whole-breast irradiation using three-dimensional conformal radiotherapy in women undergoing breast conservation for early disease yields high rates of excellent to good cosmetic outcomes in patients with large and/or pendulous breasts

PURPOSE

To report our institution's experience using prone positioning for three-dimensional conformal radiotherapy (3D-CRT) to deliver post-lumpectomy whole breast irradiation (WBI) in a cohort of women with large and/or pendulous breasts, to determine the rate of acute and late toxicities and, more specifically, cosmetic outcomes. We hypothesized that using 3D-CRT for WBI in the prone position would reduce or eliminate patient and breast size as negative prognostic indicators for toxicities associated with WBI.

METHODS AND MATERIALS

From 1998 to 2006, 110 cases were treated with prone WBI using 3D-CRT. The lumpectomy, breast target volumes, heart, and lung were contoured on all computed tomography scans. A dose of 45-50 Gy was prescribed to the breast volume using standard fractionation schemes. The planning goals were ≥95% of prescription to 95% of the breast volume, and 100% of boost dose to 95% of lumpectomy planning target volume. Toxicities and cosmesis were prospectively scored using the Common Terminology Criteria for Adverse Effects Version 3.0 and the Harvard Scale. The median follow-up was 40 months.

RESULTS

The median body mass index (BMI) was 33.6 kg/m(2), and median breast volume was 1396 cm(3). The worst toxicity encountered during radiation was Grade 3 dermatitis in 5% of our patient population. Moist desquamation occurred in 16% of patients, with only 2% of patients with moist desquamation outside the inframammary/axillary folds. Eleven percent of patients had Grade ≥2 late toxicities, including Grade 3 induration/fibrosis in 2%. Excellent to good cosmesis was achieved in 89%. Higher BMI was associated with moist desquamation and breast pain, but BMI and breast volume did not impact fibrosis or excellent to good cosmesis.

CONCLUSION

In patients with higher BMI and/or large-pendulous breasts, delivering prone WBI using 3D-CRT results in favorable toxicity profiles and high excellent to good cosmesis rates. Higher BMI was associated with moist desquamation, but prone positioning removed BMI and breast size as factors for poorer cosmetic outcomes. This series adds to the growing literature demonstrating that prone WBI may be advantageous in select patients.

Accelerated Intensity-Modulated Radiotherapy to Breast in Prone Position: Dosimetric Results

PURPOSE

To report the physics and dosimetry results of a trial of accelerated intensity-modulated radiotherapy to the whole breast with a concomitant boost to the tumor bed in patients treated in the prone position.

METHODS AND MATERIALS

Patients underwent computed tomography planning and treatment in the prone position on a dedicated treatment platform. The platform has an open aperture on the side to allow for the index breast to fall away from the chest wall. Noncontrast computed tomography images were acquired at 2.5- or 3.75-mm-thick intervals, from the level of the mandible to below the diaphragm. A dose of 40.5 Gy was delivered to the entire breast at 2.7-Gy fractions in 15 fractions. An additional dose of 0.5 Gy was delivered as a concomitant boost to the lumpectomy site, with a 1-cm margin, using inverse planning, for a total dose of 48 Gy in 15 fractions. No more than 10% of the heart and lung volume was allowed to receive >18 and >20 Gy, respectively.

RESULTS

Between September 2003 and August 2005, 91 patients were enrolled in the study. The median volume of heart that received > or =18 Gy was 0.5%, with a maximal value of 4.7%. The median volume of ipsilateral lung that received > or =20 Gy was 0.8%, with a maximum of 7.2%.

CONCLUSION

This technique for whole breast radiotherapy is feasible and enables an accelerated regimen in the prone position while sparing the lung and heart.

Long-term Clinical Outcomes of Whole-Breast Irradiation Delivered in the Prone Position

PURPOSE

The aim of this study was to evaluate retrospectively the effectiveness and toxicity of post-lumpectomy whole-breast radiation therapy delivered with prone positioning.

METHODS AND MATERIALS

Between September 1992 and August 2004, 245 women with 248 early-stage invasive or in situ breast cancers were treated using a prone breast board. Photon fields treated the whole breast to 46 to 50.4 Gy with standard fractionation. The target volume was clinically palpable breast tissue; no attempt was made to irradiate chest wall lymphatics. Tumor bed boosts were delivered in 85% of cases. Adjuvant chemotherapy and hormonal therapy were administered to 42% and 62% of patients, respectively.

RESULTS

After a median follow-up of 4.9 years, the 5 year actuarial true local and elsewhere ipsilateral breast tumor recurrence rates were 4.8% and 1.3%, respectively. The 5-year actuarial rates of regional nodal recurrence and distant metastases were 1.6% and 7.4%. Actuarial disease-free, disease-specific, and overall survival rates at 5 years were 89.4%, 97.3%, and 93%, respectively. Treatment breaks were required by 2.4% of patients. Grade 3 acute dermatitis and edema were each limited to 2% of patients. Only 4.9% of patients complained of acute chest wall discomfort. Chronic Grade 2 to 3 skin and subcutaneous tissue toxicities were reported in 4.4% and 13.7% of patients, respectively.

CONCLUSIONS

Prone position breast radiation results in similar long-term disease control with a favorable toxicity profile compared with standard supine tangents. The anatomic advantages of prone positioning may contribute to improving the therapeutic ratio of post-lumpectomy radiation by improving dose homogeneity and minimizing incidental cardiac and lung dose.