Table 4. Relationship between pneumothorax and distances.

Characteristics	Pneumothorax, n (%)		P value*
	Yes (n=61)	No (n=160)
Chest wall			<0.001
Tumor distance <20 mm	10 (8.2)	112 (91.8)
Tumor distance ≥20 mm	51 (51.5)	48 (48.5)
Skin			<0.001
Tumor edge distance <40 mm	10 (7.8)	118 (92.2)
Tumor edge distance ≥40 mm	51 (54.8)	42 (45.2)
Tumor size			0.04
<2 cm	59 (29.8)	139 (70.2)
≥2 cm	2 (8.7)	21 (91.3)

Chest wall-tumor distance: the distance from the chest wall to the edge of the tumor, skin-tumor edge distance: the distance from the chest wall to the edge of the tumor. All the distances were measured at the section where the tumor is at largest size. *, Chi-square test.