A comparison between type 3 excision of the transformation zone by straight wire excision of the transformation zone (SWETZ) and large loop excision of the transformation zone (LLETZ): a randomized study

Table 3 Comparison between the groups (SWETZ x LLETZ-cone): analysis of surgical margins in cone specimen by procedure (IFF/Fiocruz - 2008–2011)

Procedure outcome	SWETZ	%	LLETZ-cone	%	p-value	RR^*(95% CI)
Ectocervical margin
Free	37	71.2	32	59.3
Compromised	4	7.7	9	16.7
Impaired	11	21.2	13	24.1	0.2^*	1.41 (0.83-2.41)
Totals	52	100	54	100
Endocervical margin
Free	33	63.5	20	37.0
Compromised	7	13.5	15	27.8
Impaired	12	23.1	19	35.2	<0.01^†	1.72 (1.14-2.6)^‡
Totals	52		54
Stromal margin
Free	50	96.2	50	92.6
Compromised	2	3.8	2	3.7
Not evaluated		0.0	1	1.9
Impaired		0.0	1	1.9	0.6^§	1.47 (0.26-8.45)
Totals	52	100	54	100
Some margin^\|\|
All free	24	46.2	14	26.4	0.03^†	1.37 (1.01-1.84)^‡
Some margin compromised or impaired	28	53.8	39	73.6
Totals	52		53
None impaired	32	61.5	29	54.7	0.5^†	1.18 (0.75-1.85)
Some impaired	20	38.5	24	45.3
Totals	52		53

^*For this calculation, the histopathological diagnosis of margin involvement and impaired were grouped. The undesired outcome was "margin involvement or impaired" and the risk factor "LLETZ".
^†Chi-square test for analysis of "margin involvement or impaired” vs. “free” by procedure made.
^‡RAR = 26.4% (95% CI, 8.1-44,8) and NNT = 3 (95% CI, 2.2-12.4).
^§Fisher's exact test for analysis of "margin involvement or impaired" by procedure, excluding the "not evaluated" one.
^||Excluding the case of "not assessed" stromal margin.
^‡RAR = 19.7% (95% CI, 1.7-37,8) and NNT = 5 (95% CI, 2.6-58.0).
^**Chi-square test.

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