A Role for Stereotactic Body Radiation Therapy in a Multi-Modality Approach to Pulmonary Metastatic Sarcoma
Joseph A Reza, Matthew Hudnall, Amanda Sammann, Alexander Gottschalk, *David M Jablons, Ann Lazar, Steve Braunstein, *Michael J Mann
UCSF, San Francisco, CA
Background: Aggressive surgical treatment of pulmonary metastatic sarcoma represents an unusual opportunity for control of an advanced cancer. Recurrence after initial metastasectomy is common, and can lead to difficult therapeutic decisions. Stereotactic body radiation treatment (SBRT) is successful in select primary lung cancers, and may provide an opportunity for multi-modality control of recurrent metastatic sarcoma.
Methods: We reviewed our single institution experience with SBRT in the management of recurrent pulmonary metastatic sarcoma. SBRT patients were matched with patients who had undergone either one or more resections of recurrent pulmonary metastasis. Fisher's exact test, Kaplan-Meier analysis, Log rank analysis and Cox proportional hazards modeling were used to compare patients in the surgery-alone (SA) and surgery plus SBRT groups.
Results: Between 2008 and 2015, 34 patients underwent SBRT for recurrent pulmonary metastatic sarcoma. Of 90 treated lesions, only 1 demonstrated growth after SBRT (>98% local control). Two patients (5.9%) experienced severe radiation pneumonitis, which responded to steroid therapy. SBRT patients were matched, based on the number of episodes of recurrence and on initial disease-free-interval, with 96 SA patients from the same period. Radiographically-occult lesions were identified intra-operatively during 57 of 125 repeat metastasectomies (46%). Consistent with the limitations of SBRT in treating large, numerous or radiographically-occult lesions, SA patients, had, on average, larger recurrent tumors (3.2 ± 3.6 vs. 2.1 ± 1.6 cm, P<0.05) and a greater number of treated recurrent metastatic lesions (4.7 ± 5.1 vs. 2.0 ± 1.2, P < 0.01). Although patients treated with SBRT were more likely to recur sooner with additional pulmonary metastases, overall survival was better, in the surgery plus SBRT group (HR 2.4, P < 0.01); multivariate analysis, however, indicated that the difference in number and size of recurrent lesions between the two groups accounted for most of this difference in overall survival (multivariate HR 1.7, P > 0.1).
Conclusions: Patients likely benefit from initial surgical metastasectomy, which not only allows the treatment of numerous and larger lesions with lower rates of recurrence, but also enables the detection and treatment of radiographically-occult masses. SBRT, however, may offer a reasonable option for patients as part of a long-term, aggressive approach for recurrent metastatic sarcoma.
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