Introduction
VaIN is the dysplasia of the vaginal squamous epithelium, mostly
associated with persistent HR-HPV infection. VaIN is classified as
low-grade squamous intraepithelial lesion (LSIL) including VaIN1 (mild
dysplasia in the past classification) and high-grade intraepithelial
lesion (HSIL) including VaIN2,3 (moderate and severe dysplasia
respectively) according to the 2014 WHO classification of tumors of
female reproductive organs [1]. The natural history of VaIN is
similar to that of cervical intraepithelial neoplasia (CIN), but the
incidence of VaIN is less than 1% of CIN. The annual morbidity of VaIN
was about 0.2~2 per million [2], accounting for
approximately 0.4% of all squamous neoplastic lesions of the lower
genital tract [3]. The incidence of VaIN was severely underestimated
due to missed diagnosis. It was reported that VaIN consumed 8.09%,
12.45% and 13.08% of squamous lesions of the lower genital tract from
2013 to 2015 in a hospital in China [4]. The yearly increasing
detection rates of VaIN were attributable to the increased awareness of
the condition in our peers.
The management for LSIL(VaIN1) is conservative because most LSIL(VaIN1)
can regress spontaneously [5~7]. Otherwise, the rate
of HSIL(VaIN2,3) progressing to cancer was about 2~12%
[8~10]. Thus, HSIL(VaIN2,3) are usually treated
aggressively. The treatment modalities for HSIL(VaIN2,3) generally
include conservative observation, topical agents, laser ablation,
excision and so on [3]. Because of the specialty of vaginal anatomy
and sexual function, the excisional procedure is technically difficult
and adversely affects the quality-of-life. Observation or topical agents
for VaIN show uncertain effects or evident side effects. Thus, laser
ablation has become a dominant choice for VaIN with the advantages of
considerable efficacy, easy training for practitioners and few severe
complications [11]. There was obvious fluctuation in the literature
about the efficacy of laser ablation for VaIN with effective rate
varying from 47% to 100% and relapse rate varying from 20% to 57%
[8,12~18]. The samples of literature on laser
ablation for VaIN were usually small, and the essays lacked detailed
description of treatment modalities and standard follow-up schedule.
To achieve a standard method of CO2 laser ablation for
the treatment of VaIN with stably high cure rate and low complication
incidence, this study discussed the details of MTLA procedure and
related high-risk factors.