Table 3. Malignancy rates and results of follow-up of incidental lesions in the anterior mediastinal mediastinum.

Source	Study from the Early Lung Cancer Action Project	Study from the Framingham Heart Study	Study conducted at two health checkups centers
Proportion of resection	12% (5/41)	0% (0/23)	12% (51/413)
Median long-axis diameter	>30 mm	Unknown	17 mm
Malignancy rate	80% (4/5)	Unknown	23% (12/51)
Proportion of observation	88% (36/41)	100% (23/23)	88% (362/413)
Proportion of lesions with follow-up	72% (26/36)	34% (8/23)	65% (237/362)
Median follow-up interval	1 year	6.5 years	4.2 years
Results of follow-up
Proportion of growing lesions	19% (5/26)	75% (6/8)	9% (21/237)
Proportion of stable lesions	69% (18/26)	25% (2/8)	82% (195/237)
Proportion of shrinking lesions	12% (3/26)	0% (0/8)	9% (21/237)