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G.N. Cohen
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P1.08 - Poster Session/ Thymoma, Mesothelioma and Other Thoracic Malignancies (ID 224)
- Event: WCLC 2015
- Type: Poster
- Track: Thymoma, Mesothelioma and Other Thoracic Malignancies
- Presentations: 1
- Moderators:
- Coordinates: 9/07/2015, 09:30 - 17:00, Exhibit Hall (Hall B+C)
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P1.08-022 - Intraoperative Brachytherapy for Thoracic Malignancies Resected with Close or Positive Margins (ID 2795)
09:30 - 17:00 | Author(s): G.N. Cohen
- Abstract
Background:
Local recurrence is a significant problem after surgical resection of thoracic tumors, particularly when close or positive margins are anticipated. As intraoperative radiotherapy (IORT) can deliver radiation directly to the threatened margin, we used this technique in an attempt to reduce local recurrence, particularly for patients who had already received external beam radiation. We updated our experience with thoracic IORT to assess disease control and toxicity outcomes.
Methods:
We performed a retrospective review of patients undergoing permanent I-125 mesh placement or temporary Ir-192 afterloading therapy during surgical resection of primary or metastatic thoracic tumors between 2001 and 2013. In general, for I-125 brachytherapy, iodine seeds were sutured into a mesh at 1cm intervals to form a planar implant delivering 85-250Gy to the MPD, which was then sutured onto the at-risk site. For Ir-192 brachytherapy, a HAM applicator was apposed to the at-risk site, then connected to the afterloader to deliver 7.5-16Gy to a depth of 0.5cm from the applicator surface. Kaplan-Meier method was used to estimate local control and overall survival, and logrank test was used to assess the impact of various clinical or treatment factors on local control.
Results:
Fifty-nine procedures (41 permanent, 18 temporary) were performed on fifty-eight patients (median 56 years old, range 19-77). Most common tumor histologies were NSCLC (n=23), sarcoma (n=18), thymic carcinoma (n=10), and mesothelioma (n=3). Treated sites were chest wall/paraspinal (n=31), lung (n=16), and mediastinum (n=12). Thirty-four procedures were performed on patients who had previously received external beam RT (EBRT) to the area (median 53.1 Gy). Final margins were microscopically negative in 25 cases (42.4%) and positive or not assessed in the remainder. The median size of the treated area was 27cm[2] (range: 4-152cm[2]). Median followup was 28.5 months. Actuarial local control at 1 and 2 years was 68.1% and 63.4% respectively. Median survival was 46.2 months. Overall survival at 1 and 2 years was 80.2% and 70.4% respectively. No perioperative deaths occurred. There was no significant difference in local control according to margin status, brachytherapy technique, use of adjuvant EBRT, or metastatic vs. primary tumor. Two patients (3.4%) experienced grade 3+ toxicities possibly related to IORT: one patient who also received preoperative EBRT developed pneumonitis; a second patient with prior EBRT for lymphoma died from complications of SVC syndrome likely induced by radiation fibrosis. An additional 8 patients had grade 3+ postsurgical complications (such as empyema, chylothorax, and pulmonary emboli) unlikely related to IORT. Four patients had grade 2 nerve injury also unlikely related to IORT.
Conclusion:
Intraoperative brachytherapy is associated with good local control after resection of thoracic tumors felt to be at very high risk for recurrence due to close or positive margins. There is a very low incidence of severe toxicity attributable to brachytherapy. Intraoperative brachytherapy should be considered in situations where the oncologic completeness of thoracic tumor resection is in doubt.
