Breast Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_1_3331 - Inverse Planning Intensity-Modulated Radiation Therapy in Chest Wall And Lymphatic Irradiation: Early Results

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

Inverse Planning Intensity-Modulated Radiation Therapy in Chest Wall And Lymphatic Irradiation: Early Results
S. Beduk Esen1, M. T. Yilmaz1, F. Y. Yedekci1, S. Yuce Sari2, M. Gultekin3, G. Ozyigit3, and F. Yildiz3; 1Hacettepe University Medical School, Department of Radiation Oncology, Ankara, Turkey, 2Hacettepe University Faculty of Medicine, ANKARA, Turkey, 3Hacettepe University, School of Medicine, Department of Radiation Oncology, Ankara, Turkey

Purpose/Objective(s): Radiotherapy (RT) is frequently applied by forward planning intensity–modulated RT (FP-IMRT) in breast cancer. Despite the dosimetric superiority of inverse planning (IP)-IMRT, there is limited data on clinical outcome. We aimed to evaluate the early clinical results of IP-IMRT in breast cancer.

Materials/Methods: We retrospectively evaluated 253 patients treated with IP-IMRT to the chest wall (CW) and lymphatics between 2011 and 2016. In 146 patients, all lymphatics including axillary levels I-II-III and in 107 axillary level III, supraclavicular fossa (SCF) and internal mammary (IM) lymphatics were delineated. The prescription dose was 50 Gy/25 fractions. D95≥47.5 Gy, D95≥45 Gy, and CW D95≥47.5 were provided for the clinical target volume (CTV) and planning target volume (PTV) for lymphatics, and PTV for CW, respectively. A 5-mm bolus was located on the CW of all patients. Dose-volume parameters, early survival results and acute/late toxicity rates according to the RTOG toxicity scale were analyzed.

Results: Mean age was 49 years. The tumor was located in the left breast in 174 patients. 71 patients received neoadjuvant chemotherapy (CT), 170 adjuvant CT, 204 adjuvant hormonotherapy, and 67 adjuvant trastuzumab, respectively. Mean follow-up was 32 months. 26 patients developed distant metastasis. The loco-regional control rate was 100%. The 2- and 5-y overall and disease-free survival rate was 100% and 91%, and 93% and 83%, respectively. The data on CTV and criticial organ doses are shown in Table 1. 35 cases had acute grade 1, 8 grade 2, and 2 grade 3 dermatitis; and 23 had grade 1, 2 grade 2, and 1 grade 3 disphagia, respectively. 2 patients developed hypothyroidism and 2 developed lymphedema as late toxicity. No cardiac or pulmonary toxicity was observed. 2 patients developed contralateral breast cancer, and 3 developed a second primary tumor outside the breast and treatment field.

Conclusion: IP-IMRT to the CW and lymphatics is an effective and safe method. However, long term follow-up is required to evaluate the clinical results and late adverse effects such as cardiac toxicity and secondary malignancies owing to the fact that late recurrences can occur many years after RT.
Parameter
CTV CW Dmin (Gy) Dmax (Gy) Dmean (Gy) 4,431 (3,124-4,820) 5,523 (4,901-5,755) 5,132 (4,596-5,309)
CTV SCF Dmin (Gy) Dmax (Gy) Dmean (Gy) 4,578 (3,891-4,975) 5,239 (4,738-5,611) 4,984 (4,580-5,273)
CTV level 3 Dmin (Gy) Dmax (Gy) Dmean (Gy) 4,611 (4,068-4,936) 5,225 (4,275-5,556) 4,958 (4,465-5,223)
CTV axilla Dmin (Gy) Dmax (Gy) Dmean (Gy) 4,495 (3,837-4,896) 5,305 (4,970-5,638) 4,975 (4,677-5,200)
CTV IM Dmin (Gy) Dmax (Gy) Dmean (Gy) 4,429 (3,355-4,912) 5,205 (4,227-5,635) 4,911 (4,500-5,606)
Heart V10 Gy (%) V25 Gy (%) V30 Gy (%) Dort (cGy) 25 (1-65) 3 (0-10) 1.5 (0-9) 896 (432-1,587)
Ipsilateral lung V10 Gy (%) V20 Gy (%) Dmean (cGy) 51 (34-80) 25 (19-39) 1,518 (0-1,862)
Contralateral lung V10 Gy (%) V20 Gy (%) Dmean (cGy) 10 (0-39) 0.6 (0-5) 512 (195-977)
Contralateral breast Dmean (cGy) 400 (156-698)

Author Disclosure: S. Beduk Esen: None. M. Yilmaz: None. F. Yedekci: None. S. Yuce Sari: None. M. Gultekin: None.

Send Email for Melis Gultekin


Assets

TU_1_3331 - Inverse Planning Intensity-Modulated Radiation Therapy in Chest Wall And Lymphatic Irradiation: Early Results



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Inverse Planning Intensity-Modulated Radiation Therapy in Chest Wall And Lymphatic Irradiation: Early Results