Table 1.

Results of single factor K-M analysis related to recurrence of MTC

group	character	recurrence group (cases)	Non- recurrence group (cases)	Chi-square	P
Sex	male	12	30	1.542	0.214
	female	5	27
Age	≤52.5	12	31	0.925	0.336
	>52.5	5	26
Preoperative calcitonin(a*)	≤565.8 pg/ml	1	25	6.363	0.012
	>565.8 pg/ml	11	23
Postoperative calcitonin(b*)	≤45.0 pg/ml	1	33	12.786	0.000349
	>45.0 pg/ml	15	21
Tumor size	≤40.0 mm	13	53	5.837	0.016
	>40.0 mm	4	4
Capsular invasion	no	1	29	9.273	0.002
	yes	16	28
Metastatic cervical lymph nodes	no	2	31	8.442	0.004
	yes	15	26

^*Notes: a. 60 cases with preoperative calcitonin; b. 70 cases with postoperative calcitonin