Risk factors for local tumor progression after RFA of pulmonary metastases: a matched case-control study.

OBJECTIVES: Curative treatment of oligometastatic pulmonary disease aims at eradication of all metastases. Radiofrequency ablation (RFA) has been shown to be an efficient method and the frequency of local tumor progression (LTP) should be minimized. The objective of this study was to determine the morphological and treatment-related risk factors for LTP after RFA of pulmonary metastases. MATERIALS AND METHODS: All patients treated with RFA for pulmonary metastases from 2002 to 2014 were reviewed. All LTPs from 2011 to 2014 were individually matched on the basis of tumor size, number, and histology. In total, 48 LTPs and 112 controls were blindly analyzed for morphological factors including vicinity of bronchus and vessels as well as treatment-related factors such as the size of the ablation zone and ablation margins. RESULTS: In the simple regression analysis, the significant predictive variables were ≤ 5-mm distance to a large bronchus (OR = 4.94; p = 0.0095) or large vessel (OR = 7.09; p < 0.001), minimal ablation margin (≤ 5 mm (OR = 42.67; p < 0.001), and a central-peripheral ablation offset/ablation zone size > 0.36 (OR = 13.83; p = 0.013). In the multiple regression model, only a minimal ablation margin ≤ 5 mm remained a significant risk factor for LTP. CONCLUSION: Only the minimal ablation margin remains significant in the multiple regression analysis; the other factors are presumably surrogates of an insufficient ablation margin. Improvement of lung RFA outcomes can probably be obtained by immediate post RFA evaluation of ablation margins to ensure a minimal ablation margin of at least 5 mm. KEY POINTS: • A distance < 5 mm to a bronchus or vessel of over 3 mm diameter is associated with insufficient ablation margin and thus risk factors for local tumor progression after pulmonary radiofrequency ablation. • A minimal ablation margin of > 5 mm after pulmonary RFA is associated with significantly less local tumor progression and should be looked for at the end of treatment session before needle removal in order to decrease local tumor progression. • Tumor location, pleural contact, occurrence of intra-alveolar hemorrhage, pulmonary atelectasis, and pneumothorax are not associated with an increased risk of local tumor progression.

To biopsy or not to biopsy adrenal mass: is that the question?

The European Society of Endocrinology recommends surgical approach for suspicious adrenal mass with a limited role for adrenal biopsy. We report here a case of a patient with a 70 mm adrenal mass in whom adrenal biopsy avoided unnecessary adrenalectomy. An 80-year-old man was explored for a 67 × 41 mm suspect left adrenal tumor. Hormonal explorations were normal. 18F-FDG-PET/CT showed an increase in uptake of the adrenal mass (SUVmax: 44.6). As the diagnostic was uncertain, biopsy was performed. Pathology found T lymphocytic inflammatory infiltrate with CD4 phenotype without malignancy criteria. Simple close monitoring was decided in multidisciplinary meeting and with the patient's consent. At 1 and 3 months, CT and 18F-FDG-PET/CT showed a significant decrease in size and uptake of adrenal mass (40 × 20 mm and 19 × 10 mm and SUVmax 5.9 and 0.0). This report shows the interest of adrenal biopsy for well-selected cases to avoid unnecessary adrenal surgery.