Janice N. Kim

DYNAMIC CONTRAST-ENHANCED MRI KINETICS OF INVASIVE BREAST CANCER: A POTENTIAL PROGNOSTIC MARKER FOR RADIATION THERAPY

PURPOSE Our goal was to determine the correlations between dynamic contrast-enhanced MRI (DCE-MRI) kinetics of breast cancers and axillary nodal status (ANS) which may have prognostic value in designing radiation therapy recommendations. METHODS AND MATERIALS A retrospective review identified 167 consecutive patients treated with external beam radiotherapy for invasive breast cancer from Jan 1, 2006 to Nov 1, 2007. Patients with DCE-MRI kinetic data from our institution who underwent axillary surgical staging prior to chemotherapy were included. ANS was assessed as positive or negative by pathology record review. For each primary cancer, maximum tumor diameter and kinetic values for initial peak enhancement (PE), percent initial rapid enhancement (RE), and percent delayed washout enhancement (WE) were measured with a computer-aided evaluation program. Univariate, multivariate, and receiver operating characteristic curve analyses were performed according to the ANS. RESULTS Forty-six patients met study criteria, with 32 (70%) node-negative and 14 (30%) node-positive patients. Median PE was significantly greater in node-positive patients (209%) than in node-negative patients (138%, p = 0.0027). Similarly, median RE was significantly greater in node-positive patients (57%) than in node-negative patients (27%, p = 0.0436). WE was not different between groups (p = 0.9524). Median maximum tumor diameter was greater in node-positive patients (26 mm) than in node-negative patients (15 mm, p = 0.015). Multivariate analysis showed that only PE trended toward significance (p = 0.18). CONCLUSIONS DCE-MRI kinetics of primary breast cancers correlate with ANS. Multivariate analysis demonstrates the correlation is not due simply to underlying lesion size. If validated prospectively, DCE-MRI kinetics may aid as a tool in selecting patients or designing fields for radiation therapy.

Dynamic contrast-enhanced magnetic resonance imaging and invasive breast cancer: Primary lesion kinetics correlated with axillary lymph node extracapsular extension

To determine if dynamic contrast‐enhanced (DCE) magnetic resonance imaging (MRI) peak enhancement (PE) of primary breast cancer can predict the presence of lymph node extracapsular extension (LNECE) in patients with axillary metastatic disease.

A Phase II Study of Radiotherapy and Concurrent Paclitaxel Chemotherapy in Breast-Conserving Treatment for Node-Positive Breast Cancer

PURPOSE Administering adjuvant chemotherapy before breast radiotherapy decreases the risk of systemic recurrence, but delays in radiotherapy could yield higher local failure. We assessed the feasibility and efficacy of placing radiotherapy earlier in the breast-conserving treatment course for lymph node-positive breast cancer. METHODS AND MATERIALS Between June 2000 and December 2004, 44 women with node-positive Stage II and III breast cancer were entered into this trial. Breast-conserving surgery and 4 cycles of doxorubicin (60 mg/m(2))/cyclophosphamide (600 mg/m(2)) were followed by 4 cycles of paclitaxel (175 mg/m(2)) delivered every 3 weeks. Radiotherapy was concurrent with the first 2 cycles of paclitaxel. The breast received 39.6 Gy in 22 fractions with a tumor bed boost of 14 Gy in 7 fractions. Regional lymphatics were included when indicated. Functional lung volume was assessed by use of the diffusing capacity for carbon monoxide as a proxy. Breast cosmesis was evaluated with the Harvard criteria. RESULTS The 5-year actuarial rate of disease-free survival is 88%, and overall survival is 93%. There have been no local failures. Median follow-up is 75 months. No cases of radiation pneumonitis developed. There was no significant change in the diffusing capacity for carbon monoxide either immediately after radiotherapy (p = 0.51) or with extended follow-up (p = 0.63). Volume of irradiated breast tissue correlated with acute cosmesis, and acute Grade 3 skin toxicity developed in 2 patients. Late cosmesis was not adversely affected. CONCLUSIONS Concurrent paclitaxel chemotherapy and radiotherapy after breast-conserving surgery shortened total treatment time, provided excellent local control, and was well tolerated.

Solitary Orbital Metastasis 35 Years after a Diagnosis of Lobular Carcinoma in Situ

This report describes a solitary orbital metastasis of lobular carcinoma in a woman 35 years after diagnosis of right breast lobular carcinoma in situ (LCIS). After partial response to anastrozole, the patient was treated with proton radiotherapy to 45 cobalt gray equivalents (CGE) with an excellent response. We additionally discuss treatment strategies for this rare metastatic site.

SU-G-TeP1-11: Predictors of Cardiac and Lung Dose Sparing in DIBH for Left Breast Treatment

PURPOSE This retrospective study of left sided whole breast radiation therapy (RT) patients investigates possible predictive parameters correlating to cardiac and left lung dose sparing by deep inspiration breath-hold (DIBH) technique compared to free-breathing (FB). METHODS Thirty-one patients having both DIBH and FB CT scans were included in the study. All patients were planned with a standard step-and-shoot tangential technique using MV photons, with prescription of 50Gy or 50.4Gy. The displacement of the breath hold sternal mark during DIBH, the cardiac contact distances of the axial (CCDax) and parasagittal (CCDps) planes, and lateral-heart-to-chest (LHC) distance on FB CT scans were measured. Lung volumes, mean dose and dose-volume histograms (V5, V10 and V20) were analyzed and compared for heart and left lung for both FB and DIBH techniques. Correlation analysis was performed to identify the predictors for heart and left lung dose sparing. Two-tailed Students t-test and linear regression were used for data analysis with significance level of P≤0.05. RESULTS All dosimetric metrics for the heart and left lung were significantly reduced (P<0.01) with DIBH. Breath hold sternal mark displacement ranged from 0.4-1.8 cm and correlated with mean (P=0.05) and V5 (P=0.02) of heart dose reduction by DIBH. FB lung volume showed correlation with mean lung dose reduction by DIBH (P<0.01). The FB-CCDps and FB-LHC distance had strong positive and negative correlation with FB mean heart dose (P<0.01) and mean heart dose reduction by DIBH (P<0.01), respectively. FB-CCDax showed no correlation with dosimetric changes. CONCLUSION DIBH technique has been shown to reduce dose to the heart and left lung. In this patient cohort, FB-CCDps, FB-LHC distance, and FB lung volume served as significant predictors for heart and left lung. These parameters can be further investigated to be used as a tool to better select patients who will benefit from DIBH.

SU-E-J-32: Calypso(R) and Laser-Based Localization Systems Comparison for Left-Sided Breast Cancer Patients Using Deep Inspiration Breath Hold

PURPOSE Our institution uses a manual laser-based system for primary localization and verification during radiation treatment of left-sided breast cancer patients using deep inspiration breath hold (DIBH). This primary system was compared with sternum-placed Calypso(R) beacons (Varian Medical Systems, CA). Only intact breast patients are considered for this analysis. METHODS During computed tomography (CT) simulation, patients have BB and Calypso(R) surface beacons positioned sternally and marked for free-breathing and DIBH CTs. During dosimetry planning, BB longitudinal displacement between free breathing and DIBH CT determines laser mark (BH mark) location. Calypso(R) beacon locations from the DIBH CT are entered at the Tracking Station. During Linac simulation and treatment, patients inhale until the cross-hair and/or lasers coincide with the BH Mark, which can be seen using our high quality cameras (Pelco, CA). Daily Calypso(R) displacement values (difference from the DIBH-CT-based plan) are recorded. The displacement mean and standard deviation was calculated for each patient (77 patients, 1845 sessions). An aggregate mean and standard deviation was calculated weighted by the number of patient fractions.Some patients were shifted based on MV ports. A second data set was calculated with Calypso(R) values corrected by these shifts. RESULTS Mean displacement values indicate agreement within 1±3mm, with improvement for shifted data (Table). CONCLUSION Both unshifted and shifted data sets show the Calypso(R) system coincides with the laser system within 1±3mm, demonstrating either localization/verification system will Resultin similar clinical outcomes. Displacement value uncertainty unilaterally reduces when shifts are taken into account.

Learning Curve in Multi-Catheter Partial Breast Irradiation

Results: For all patients treated, mean of 98.9% of GTV and 91.6% of PTV received at least 100% of prescribed dose. D90 for GTV was 128% and for PTV was 108%. DHI was 0.76 and COIN was 0.70. Mean maximum lung dose was 35% of prescribed dose and mean maximum skin dose was 75% of prescribed dose. There was no difference in tumor volume coverage between first five plans performed at our institution and most recent 20 plans (PTV V100 = 90.4% vs 89.9%). There also was no significant difference in dose homogeneity or normal tissue dose, but conformality of initial plans was not as good as subsequent plans (COIN=0.59vs0.72,p\0.01).Comparisonofthefirstfiveplansofbothpractitioner andtheremainingplansalsodidnotidentify differencein tumorvolumecoverage(V10091%vs91%)orhomogeneity(DHI= 0.75vs0.77),butconformality improvedinlater plans (COIN 0.61 vs 0.72, p\0.01). There was a trend to using a higher number of catheters in initial implants compared to later plans. Conclusions:Useoftemplateguidanceforcatheterinsertionallowsforhighqualitydosimetricplans,withexcellenttumorvolume coverage, dose homogeneity and conformality. Achieving high quality multi-catheter implants does not necessarily require extensive institutional or individual practitioner experience, although plan conformality improves with experience. Author Disclosure: A.V. Taira, None; D. Swedler, None; L. Young, None; T. Arbuckle, None; W. Wang, None; J. Kim, None.