Value of serial magnetic resonance imaging in the assessment of brain metastases volume control during stereotactic radiosurgery

Table 2 Primary cancer types and effective time point for magnetic resonance imaging follow-up to provide useful information for the treatment decision

Primary cancer type	No. of lesions	%4	Reduced in size at 6 wk1	%4	Pseudo-progression (9 wk)2	%4	True-progression (12 mo)3	%4
Non-small cell lung carcinoma	19	36	12	22	8	15	1	2
Breast carcinoma	16	29	11	20	7	13	4	7
Renal cell carcinoma	9	16	1	2	0	0	6	11
Melanoma	10	19	1	2	0	0	8	15
Total	54	100	25	46	15	28	19	35

¹Number of lesions reduced in size at 6-wk follow-up;

²Number of lesions that presented a transient volume growth (pseudo-progression) at 9-wk follow-up;

³Number of lesions that presented final volume growth (true-progression) at 12-mo follow-up;

⁴Percentage of lesions computed over the total number of lesions (n = 54).