Abstract | May 4, 2021
A Rare Complication of Breast Cancer Treatment: Radiation Induced Sarcoma
Learning Objectives
- Describe the clinical presentation of an uncommon consequence years after radiation therapy;
- Enhance awareness and early detection by clinicians, which is essential to improve outcomes of patients with RIS;
- Describe management for RIS.
Introduction:
Sarcomas are a rare type of tumor that account for about one percent of all cancer, arises from mesenchymal cells, and are often asymptomatic until they become very large. Post-radiation sarcomas, or radiation induced sarcomas (RIS), are rare complications of radiotherapy that occur within a previously irradiated field over a latency period of 10 to 15 years. RIS has an incidence of 3.2 per 1,000 patients, and accounts for 0.5% to 5.5% of all sarcomas. Despite RIS having a poor prognosis, with a 5-year survival rate of about 40%, surgical resection is the standard treatment to improve patient outcome, if able to obtain an adequate surgical margin.
Case Presentation:
A case of a 64 year old female with a history of hypertension, Von Willebrand disease, osteoporosis, and right breast cancer, that comes to the surgeon’s office with a recent diagnosis of Sarcoma. In 2010, she was diagnosed with HER 2 positive, estrogen positive right breast intraductal cancer. Started treatment with neoadjuvant chemotherapy Taxotere (TCH) followed by a lumpectomy. After lumpectomy surgery, the patient was treated with 36 sections of radiotherapy. She completed one year of Herceptin and has been on surveillance with Femara. In 2020, ten years after undergoing radiation therapy, the patient noticed a new hard lump on her right chest, and symptoms of persistent pain in the right hemithorax. Chest CT with IV contrast results shows findings of an extrinsic pleural-based lobulated solid mass with heterogeneous area of contrast enhancement at the upper right hemithorax from apex to the midlung zone, measuring approximately 13.3 cm x 6.7 cm x 14.5 cm. Findings compatible with metastatic disease. There was a prominent mass effect/compression on the right upper lobe at the right internal mammary artery. Additionally, erosive osteocytic changes involving the adjacent anterolateral right 1st to 3rd ribs, concerning intraosseous invasion of tumor. After the case was reviewed by the surgeon, thoracic surgery was scheduled.
Final/Working Diagnosis:
Sarcoma of Thoracic Wall
Management/Outcome/Follow-up:
If there is no contraindication, the established treatment for RIS is surgical resection that includes wide excision. Previous irradiation to the area impairs anatomic and tumor planes, preventing surgeons from appreciating true tumor margins, therefore the procedure is adapted according to the findings during surgery. The patient underwent a sternotomy with excision of the tumor, biopsies of right upper and lower lobes of the lung, thymectomy, and chemical tumor ablation with alcohol 100%. Findings during surgery include a 2.5 pound huge multilobulated right chest wall tumor invading the right upper and lower lobes of the lung, attached to the pericardium, superior vena cava, and the innominate vein. There was no mediastinal or right lung hilar lymphadenopathy, and the frozen section report shows a highly poorly differentiated sarcoma. Specimens were biopsied for further examination from the chest wall tumor with portions of the right upper and
lower lobes of the lung, and the thymus gland. Surgical pathology report reveals epithelioid cell positive for keratin, p53, and TTF-1, and negative for GATA3, which supports a diagnosis of Sarcomatoid Carcinoma most likely from lung. Patient remained admitted in the hospital for 16 days post surgery and was then discharged home to continue monitoring and adjuvant therapy with a hemato-oncologist.
