Differentiated vulvar intraepithelial neoplasia long-term follow up and prognostic factors: An analysis of a large historical cohort.

INTRODUCTION: Differentiated vulvar intraepithelial neoplasia (dVIN) is a high-risk preinvasive vulvar lesion and precursor of human papillomavirus-independent vulvar squamous cell carcinoma (VSCC). Due to its rarity, literature data on its malignant potential are scant. The aim of the study is to assess the risk of developing VSCC in patients surgically treated for dVIN not associated with VSCC (solitary dVIN) and the risk of VSCC recurrence in patients treated for dVIN associated with VSCC (dVIN-VSCC) at first diagnosis. MATERIAL AND METHODS: A historical cohort study was performed in a northern Italy referral center for vulvar neoplasms. All consecutive women surgically treated for histologically confirmed dVIN from 1994 to 2021 were collected. Primary outcome was cancer risk or recurrent cancer risk, secondary outcomes were risk factors associated with VSCC development or recurrence. Kaplan-Meier method and log-rank test were used to estimate cancer risk or recurrent cancer risk differences and uni- and multivariate Cox regression analyses to identify risk factors associated with VSCC development in solitary dVIN and recurrence of dVIN-VSCC. RESULTS: Seventy-six patients with dVIN at preoperative biopsy were included: at excisional specimens 44 were solitary dVIN and 32 were dVIN-VSCC. The absolute risk of VSCC development after solitary dVIN treatment was 43.2% with median time to to VSCC diagnosis of 25.4 months (range 3.5-128.0 months). VSCC recurrence absolute risk in treated dVIN-VSCC patients was 31.3% with median time to VSCC recurrence of 52.9 months (range 6.5-94.8 months). At uni- and multivariate regression analyses, only compliant topical ultrapotent corticosteroid treatment after solitary dVIN excision showed an ability to prevent VSCC development. No protective effect by corticosteroid treatment was shown for VSCC recurrence in dVIN-VSCC patients. Smoking was associated with higher cancer recurrence risk in dVIN-VSCC patients on both uni- and multivariate regression analyses. CONCLUSIONS: Patients with dVIN have a high risk of developing both primary and recurring VSCC. Early recognition, long-term follow up, and compliant ultrapotent topical corticosteroid treatment are recommended.

HPV-independent and HPV-associated vulvar squamous cell carcinoma: two different cancers.

OBJECTIVES: We report the disease-specific survival of patients with human papillomavirus (HPV)-associated and HPV-independent vulvar squamous cell carcinomas and determine whether differences exist and are independent of stage and age at diagnosis. METHODS: This was a retrospective cohort study with case note and pathology slide review of 265 consecutive women with vulvar squamous cell carcinoma. These patients were treated over a 15 year period (2001-2016) at a centralized cancer center covering half the population of New Zealand. The women's cancers were categorized dependent on their adjacent pathology, immunohistochemistry and HPV status following expert slide review. Disease-specific survival was calculated using Kaplan-Meier univariable and Cox proportional hazard (adjusting for stage, age, and HPV dependence) multivariable methods. RESULTS: The survival analysis included 236 women with follow-up to 96 months; 124 of them were HPV-associated, 95 HPV-independent, and 17 were unclassifiable. Of the 236 women, 146 were stage 1 (92 HPV-associated, 49 HPV-independent, 5 unclassifiable), 13 stage II (7 HPV-associated, 6 HPV-independent), 62 stage III (20 HPV-associated, 34 HPV-independent, 8 unclassifiable) and 15 stage IV (5 HPV-associated, 6 HPV-independent, 4 unclassifiable). HPV-independent vulvar squamous cell carcinomas had significantly worse survival than HPV-associated vulvar squamous cell carcinomas independent of stage and age at diagnosis (HR 3.6 (95% confidence interval (CI): 1.6 to 8.2)). Tumors that were unclassifiable by HPV type also had significantly worse survival than HPV-associated tumors independent of stage and age at diagnosis (HR 6.2 (95% CI: 2.4 to 16.0)). CONCLUSIONS: HPV-independent vulvar squamous cell carcinomas present more frequently in older women than HPV-associated tumors. However, the poorer prognosis is independent of age and stage, with worse outcomes even in early stage disease.

Prevaccine Human Papillomavirus Status in Invasive and Intraepithelial Lesions of the Vulva in New Zealand Women.

OBJECTIVE: The human papillomavirus (HPV) vaccine, introduced in New Zealand (NZ) in 2008, is predicted to substantially lower the incidence of HPV-associated precancers and cancers. The aim of this study is to estimate the proportion of vulvar intraepithelial neoplasia (VIN) lesions and invasive vulvar squamous cell carcinomas (SCCV) attributable to HPV in NZ women treated by the Auckland Regional Gynecological Oncology Service, covering an estimated 50% of the NZ population. MATERIALS AND METHODS: Polymerase chain reaction and reverse hybridization were used to analyze retrospective histologically proven SCCV from 1990 to 2007 and VIN lesions from 2000 to 2007 for HPV content and genotype in a collaborative study with the Catalan Institute of Oncology. Immunohistochemistry for p16INK4a was performed on SCCV, which were attributed to HPV if both tested positive. RESULTS: Polymerase chain reaction testing for HPV content and genotype was performed on 66 VIN lesions (all high-grade squamous intraepithelial lesions) and 189 SCCV. In addition, p16 immunohistochemistry was performed on 168 of the 189 SCCV (88.9%) tested for HPV-DNA. Overall, 61 SCCV cases (36.3%) were attributed to HPV (HPV+/p16+), and 89 SCCV cases (53%) were considered to have developed independently of HPV (HPV-/p16-). Known high-risk HPV genotypes were present in 96.8% of HPV-DNA-positive vulvar high-grade squamous intraepithelial lesions and 98.4% of HPV-attributable SCCV. Human papillomavirus 16 represented the most common genotype in both. CONCLUSIONS: Overall, the HPV vaccine is likely to substantially alter the profile of SCCV in our region. The results provide a baseline assessment of the HPV status of vulvar neoplasia before the introduction of the HPV vaccine.

Trends in HPV-dependent and HPV-independent vulvar cancers: The changing face of vulvar squamous cell carcinoma.

OBJECTIVE: To investigate the incidence and survival of Vulvar Squamous Cell Carcinoma (VSCC) by etiology over a 27 year period. METHOD: Retrospective case-note and pathology slide review of 390 consecutive VSCC, treated at a Centralized Cancer Centre covering half New Zealand's population, 1990-2016. Incidence was calculated in 5-6 year cohorts and correlated with precursor of the VSCC, age and stage. RESULTS: Age-standardized incidence of all VSCC did not change significantly, however age standardized incidence of HPV-dependent VSCC increased significantly, from 0.55/100,000 (95% CI 0.38-0.72) in 1991-2000 to 0.83/100,000 (95% CI 0.68-0.97) in 2001-2016, with a significant decrease in the incidence of HPV-independent VSCC, from 0.76/100,000 (95% CI 0.58-0.95) to 0.54/100,000 (95%CI 0.43-0.65). HPV-dependent VSCC in women ≥50 years increased significantly from 0.75/100,000 (95% CI 0.45-1.17) to 1.43/100,000 (95% CI 1.14-1.77), with no significant change seen in younger women. HPV-independent VSCC in women ≥50 years has decreased significantly from 2.53/100,000 (95% CI 1.95-3.23) to 1.62/100,000 (95% CI 1.31-1.98) with no change in younger women. The proportion of HPV-dependent VSCC has increased from 25% to 50%. Age standardized death rate from VSCC has not changed significantly from 0.22/100,000 (95% CI 0.10-0.34) in 2001-5 to 0.27/100,000 (95% CI 0.15-0.40) in 2011-16. Five year survival for HPV-dependent VSCC was 93% and 68% for HPV-independent VSCC (p < .0001). CONCLUSIONS: HPV-dependent VSCC incidence has increased significantly and now accounts for half of VSCC, with a significant rise in women over 50. HPV-dependent and independent VSCC have different prognoses and should be registered and investigated separately.

Differences Between Squamous Intraepithelial Lesions of the Vulva and the Cervix.

The Lower Anogenital Squamous Terminology project and subsequent publication have grouped preinvasive human papillomavirus-associated squamous intraepithelial lesions of the lower genital tract and adjacent skin as a single entity. We are concerned that as a result of this grouping, some of the clinically relevant differences may not be taken into consideration. We describe differences between high-grade squamous intraepithelial lesion of the vulva and cervix (vulvar intraepithelial neoplasia and cervical intraepithelial neoplasia), in embryology (arising from ectoderm vs mesoderm), clinical presentations (symptoms or signs due to many vulvar lesions vs abnormal cytology), examination techniques and diagnosis (clinical examination of potentially widely involved areas vs colposcopy of the transformation zone), natural history, management, and follow-up requirements (long-term clinical assessment vs cytology and human papillomavirus testing). We believe that failure to understand these important differences will lead to errors in management.

Outcomes for women without conventional treatment for stage 1A (microinvasive) carcinoma of the cervix.

BACKGROUND: An unethical clinical study that entailed withholding treatment from women diagnosed with cervical intraepithelial neoplasia 3 (CIN3) was conducted at National Women's Hospital, Auckland, New Zealand. Women with microinvasive carcinoma of the cervix also had treatment withheld. AIMS: To describe the management and outcomes for women with microinvasive carcinoma for many of whom conventional treatment was withheld. MATERIALS AND METHODS: Retrospective cohort study of women with a diagnosis of stage 1A cervical carcinoma at National Women's Hospital. Medical records, cytology and histopathology were reviewed and data linked with cancer and death registries up to December 2000. RESULTS: Between 1955 and 1976, 62 women were initially diagnosed with stage 1A cervical cancer and 20 were diagnosed during follow up (to 1995). Sixty of the 82 women had initial management characterised as 'probably non-curative'; 20 of these received only a small diagnostic excision. Women in the latter group were more likely to: (i) subsequently have positive cytology (P < 0.0005), (ii) have untreated positive cytology (P = 0.02), and (iii) undergo multiple biopsies after initial management (P = 0.001). Of the women who received only a small diagnostic excision, eight of 20 developed invasive carcinoma of the cervix (≥ stage 1B) or vaginal vault, compared to two of 22 women who received initial treatment characterised as 'probably curative'. CONCLUSIONS: Women with microinvasive carcinoma were included in a natural history study of CIN3; they underwent numerous procedures designed to observe rather than treat their condition, and had a substantial risk of invasive cancer.

The Natural History of Vulvar Intraepithelial Neoplasia, Differentiated Type: Evidence for Progression and Diagnostic Challenges.

Squamous cell carcinoma of the vulva (SCCV) develops through either human papillomavirus (HPV)-dependent or HPV-independent pathways. Approximately 60% of SCCV arise independently of HPV, commonly in a background of an inflammatory dermatosis, particularly lichen sclerosus. The likely direct precursor to most of these lesions is vulvar intraepithelial neoplasia (VIN), differentiated type (dVIN), although the evidence is largely circumstantial. There are few reports of progression to carcinoma, and the natural history of this pathway is not well understood. Nevertheless, dVIN is widely regarded as a potentially aggressive lesion. We identified dVIN adjacent to SCCV in 97 of 212 women (45.8%). Twenty-four of the 97 women (24.7%) had biopsies performed at least 6 mo before presentation with SCCV; slides for 47 biopsies from 21 women were available for review. dVIN was identified in 18 biopsies from 8 women (38.1%), which in 14 biopsies had been previously unrecognized. The subsequent cancer developed in the same region as the previous biopsy showing dVIN in 6 of the 8 women. The median interval between biopsy and invasive cancer was 43.5 mo (range, 8-102 mo). dVIN-associated SCCV was strongly associated with both lichen sclerosus, and HPV-negative status compared with usual type VIN (relative risk=38.35 (9.755-150.8) and 0.06485 (0.02764-0.1522), respectively). This study adds to the evidence linking dVIN with SCCV, and indicates that both clinical and histologic underrecognition contribute to the apparent rarity of dVIN as a solitary diagnosis. The morphologic spectrum of dVIN is likely to be wider than commonly appreciated; however, histologically defining the lower threshold is difficult and controversial.

A case series of young women with spontaneous regression of vulval intraepithelial neoplasia: Demographics and associated HPV genotypes.

OBJECTIVE: To review the clinical features, demography and human papillomavirus (HPV) genotype in a group of young women with usual type vulval intraepithelial neoplasia (VIN) whose lesions regressed spontaneously. MATERIALS AND METHODS: A retrospective case note review was made of the records of women with a diagnosis of usual type VIN whose lesions resolved spontaneously. The clinical features, demography, associated conditions, time to regression and follow-up data were extracted. Stored paraffin-embedded biopsy tissue was tested for the presence and genotype of HPV. RESULTS: Fifty-four women were identified. The median age at diagnosis was 19 years. Forty-four women (81%) were of non-European ethnicity. The median time to regression was 9 months. In 44 (81%) cases, the lesion was an incidental finding during clinical examination. The majority of lesions were multifocal and pigmented (44 (81%) and 48 (89%), respectively). HPV was detected in 40 (87%) of the 46 available biopsy samples, and HPV genotype 16 was identified in 33 (82.5%). Recurrences of usual type VIN occurred in three women, and these all resolved spontaneously. CONCLUSION: Women diagnosed with usual type VIN which resolves spontaneously are very young, mainly non-European, and usually present with multiple, asymptomatic pigmented lesions. HPV genotypes and their frequencies are similar to those detected in older women with usual type VIN. This clinically defined group of women may be managed by observation alone if follow-up is assured.

Spindle cell carcinoma of the vulva: a series of 4 cases and review of the literature.

Spindle cell or sarcomatoid squamous cell carcinoma is an uncommon variant of squamous cell carcinoma of the vulva (SCCV) with only 12 well-documented cases reported to date. Morphologically tumors may be biphasic or monophasic, and uncommonly include heterologous elements. Only 1 reported vulval tumor has previously been investigated for human papillomavirus DNA content. We describe 4 women with spindle cell (sarcomatoid) SCCV, 3 of which occurred de novo and 1 followed radiotherapy for previous SCCV. The tumors in all 4 women arose in a background of lichen sclerosus, and 3 were associated with vulval intraepithelial neoplasia differentiated (simplex) type. All tumors were negative for human papillomavirus DNA on polymerase chain reaction analysis. One case is the second reported with malignant heterologous elements described in the vulva. These tumors seem to be more aggressive than conventional SCCV.

Aggressive angiomyxoma [corrected] of the female genital tract and pelvis--clinicopathologic features with immunohistochemical analysis.

Aggressive angiomyxoma (AA) is a benign, slow-growing tumor that characteristically occurs in women of reproductive age. Local recurrence is cited in 30% to 40% of cases. Wide local excision is the treatment of choice. However, recent reports suggest a role for hormone manipulation in the management of these tumors. The morphology and immunophenotype of AA overlap with that of other, mainly benign vulvovaginal mesenchymal tumors. Diagnosis rests primarily on hematoxylin and eosin staining features, and distinction is important in determining appropriate treatment and follow-up. Rearrangement of HMGA2 has been shown in AA, and reports suggest that HMGA2 immunohistochemistry may have a role in the routine diagnosis of AA, its distinction from mimics, and in the evaluation of margins. Furthermore, CDK4 immunopositivity has been described in AA. We describe a series of 9 cases of AA with typical histology and long-term follow-up, and evaluate the role of HMGA2, CDK4, estrogen, and progesterone immunohistochemistry. One of 9 women (11%) experienced recurrence, with the second at 17 years, which is the longest recorded in the English literature. HMGA2 immunohistochemistry was positive in 37.5% of cases, consistent with the reported frequency of HMGA2 gene rearrangement, and negative in all benign mimics. CDK4 immunoreactivity was weak, diagnostically not helpful, and of uncertain significance. Immunohistochemistry for estrogen and progesterone were positive in 87.5% of AAs, and were widely positive in control groups.

Multifocal multicentric squamous cell carcinomas arising in vulvovaginal lichen planus.

OBJECTIVE: To describe a case of squamous cell carcinoma (SCC) arising in vulvovaginal lichen planus (LP) and to highlight difficulties in occult cancer surveillance in the setting of severe vaginal stenosis. CASE: A 67-year-old woman with long-standing systemic and vulvovaginal LP presented with multifocal vulvar SCC. Four months after radical vulvectomy and bilateral groin node dissection for stage IB carcinomas, she presented with stage III vaginal SCC arising in an obliterated vagina. CONCLUSIONS: Multifocal, multicentric carcinomas may arise in the vulva and stenosed vagina in women with LP.

Consequences in women of participating in a study of the natural history of cervical intraepithelial neoplasia 3.

BACKGROUND: A retrospective cohort study was performed in 1063 women diagnosed with cervical intraepithelial neoplasia grade 3 (CIN3) (previously termed carcinoma in situ- CIS) in the National Women's Hospital, Auckland, New Zealand. The study describes the clinical management and outcomes for women with CIN3 diagnosed in the decade of 1965-1974, when treatment with curative intent was withheld in an unethical clinical study of the natural history of CIS. A comparison is made with women who were diagnosed earlier (1955-1964) and later (1975-1976). AIMS: The aim of the study is to record the medical encounters, frequency and management of cytological abnormalities and the occurrence of invasive cancers. The medical records, cytology and histopathology were reviewed and data linked with cancer and death registers. RESULTS: Women diagnosed with CIN3 in 1965-1974 (n = 422), compared with those diagnosed earlier (n = 385) or later (n = 256): (i) were less likely to have initial treatment with curative intent (51% vs 95 and 85%, respectively); (ii) had more follow-up biopsies (P < 0.0005); (iii) were more likely to have positive cytology during follow-up (P < 0.005) and positive smears that were not followed within six months by a treatment with curative intent (P < 0.005); and (iv) experienced a higher risk of cancer of the cervix or vaginal vault (RR = 3.3 compared with the first period, 95% CI: 1.7-5.3). Among women diagnosed in 1965-1974, those initially managed by punch or wedge biopsy alone had a cancer risk ten times (95% CI: 3.9-25.7) higher than women initially treated with curative intent. CONCLUSIONS: During the 'clinical study' (1965-1974), women underwent numerous interventions that were aimed to observe rather than treat their condition, and their risk of cancer was substantially increased.

Vaginal stenosis after toxic epidermal necrolysis.

A 17-year-old adolescent girl developed severe toxic epidermal necrolysis after inhalation of methamphetamine. Recovery was complicated by vaginal synechiae and occlusion necessitating surgery.

The VP7 genes of two G9 rotaviruses isolated in 1980 from diarrheal stool samples collected in Washington, DC, are unique molecularly and serotypically.

In a retrospective study of archival diarrheal stool samples collected from 1974 to 1991 at Children's Hospital National Medical Center, Washington, DC, we detected three genotype G9P[8] viruses in specimens collected in 1980, which represented the earliest human G9 viruses ever isolated. The VP7 genes of two culture-adapted 1980 G9 viruses were phylogenetically related closely to the lineage 2 G9 virus VP7 gene. Unexpectedly, however, the VP7s of the 1980 G9 viruses were more closely related serotypically to lineage 3 VP7s than to lineage 2 VP7, which may be supported by amino acid sequence analyses of the VP7 proteins.

A medical journal editor's role in exposing an unethical research study.

The involvement of Dr. Richard Mattingly, Editor of Obstetrics & Gynecology between 1972 and 1985, in the publication of an article on carcinoma in situ (CIS) of the cervix, facilitated exposure of an unethical study into the natural history of CIS of the cervix (now termed cervical intraepithelial neoplasia 3) by Dr. Herbert Green. The object of Dr. Green's study was to verify his premise that CIS was not a precursor of invasive cancer, and he published his "atypical viewpoint" that CIS was a benign disorder in international medical journals and the lay press. Alarmed by the number of women developing cancer and frustrated by the failure of the hospital authorities to deal with the problem, Dr. Bill McIndoe began presenting his interpretation of Dr. Green's study at international scientific meetings. Dr. Mattingly was aware of both Dr. Green's previous publications and the difficulties facing Dr. McIndoe, and he encouraged Dr. McIndoe to publish his data in Obstetrics & Gynecology. The correspondence between Dr. Mattingly, a senior U.S. academic and journal editor wishing to publish important scientific data, and Dr. McIndoe, an unknown antipodean clinician intent on revealing an unethical experiment, provides important lessons for all who practice medicine, in particular those in positions of responsibility.

Ancient schwannoma of the vulva.

BACKGROUND: Ancient schwannoma, a variant of schwannoma (previously termed neurilemoma), arises from the Schwann cells of the nerve sheath. It presents with swelling, pain, or paresthesia. CASE: A 53-year-old woman presented with a history of a left vulvar swelling, which had been present for many years. The tumor was slowly increasing in size and affected activities such as sitting and walking. Occasionally, she experienced a burning sensation at the site of the swelling. Surgical excision was undertaken, and histology demonstrated an ancient schwannoma. CONCLUSION: The characteristic histological appearance seen in ancient schwannoma should prevent the erroneous diagnosis of a malignant tumor. Malignant change is exceedingly rare. Treatment is complete surgical excision.

Vulvar cancer and the need for awareness of precursor lesions.

Vulvar cancer continues to rise in incidence. In the absence of screening, attempts to reduce this cancer must focus on recognizing precursor lesions, namely, lichen sclerosus and vulvar intraepithelial neoplasia (VIN). The steep rise in human papillomavirus-repeated VIN will fall after the introduction of vaccination against human papillomavirus; in the meantime, those patients with VIN must be treated and then reviewed carefully and frequently. Lichen sclerosus has a 3% to 5% risk of progressing to vulvar cancer. Recommendations about which patients require referral to and follow-up by specialists/specialist clinics are given.

Natural history of cervical neoplasia and risk of invasive cancer in women with cervical intraepithelial neoplasia 3: a retrospective cohort study.

BACKGROUND: The invasive potential of cervical intraepithelial neoplasia 3 (CIN3; also termed stage 0 carcinoma) has been poorly defined. At the National Women's Hospital, Auckland, New Zealand, treatment of CIN3 was withheld from a substantial number of women between 1965 and 1974 as part of an unethical clinical study. The resulting variation in management allows comparison of the long-term risk of invasive cancer of the cervix in women whose lesion was minimally disturbed with those who had adequate initial treatment followed by conventional management. We aimed to estimate the long-term risk of invasive cancer in these two groups of women. A judicial inquiry referred for independent clinical review in 1988 all women for whom there remained doubt about the adequacy of their management. METHODS: Between February, 2001, and December, 2004, medical records, cytology, and histopathology were reviewed for all women with CIN3 diagnosed between 1955 and 1976, whose treatment was reviewed by judicial inquiry and whose medical records could be located, and linkages were done with cancer and death registers and electoral rolls. To take into account the probability that the CIN3 lesion had been completely removed, we classified adequacy of treatment by type of procedure, presence of CIN3 at the excision margin, and subsequent cytology. The primary outcome was cumulative incidence of invasive cancer of the cervix or vaginal vault. Follow-up continued until death or Dec 31, 2000, whichever came first. Analyses accounted for procedures during follow-up. FINDINGS: 1229 women whose treatment was reviewed by the judicial inquiry in 1987-88 were included. Of these, 48 records (4%) could not be located and 47 women (4%) did not meet the inclusion criteria. At histopathological review, a further 71 (6% of 1134) women were excluded because the review diagnosis was not CIN3. We identified outcomes in the remaining 1063 (86% of 1229) women diagnosed with CIN3 at the hospital in 1955-76. In 143 women managed only by punch or wedge biopsy, cumulative incidence of invasive cancer of the cervix or vaginal vault was 31.3% (95% CI 22.7-42.3) at 30 years, and 50.3% (37.3-64.9) in the subset of 92 such women who had persistent disease within 24 months. However, cancer risk at 30 years was only 0.7% (0.3-1.9) in 593 women whose initial treatment was deemed adequate or probably adequate, and whose treatment for recurrent disease was conventional. INTERPRETATION: This study provides the most valid direct estimates yet available of the rate of progression from CIN3 to invasive cancer. Women with untreated CIN3 are at high risk of cervical cancer, whereas the risk is very low in women treated conventionally throughout.

Efficacy of a quadrivalent prophylactic human papillomavirus (types 6, 11, 16, and 18) L1 virus-like-particle vaccine against high-grade vulval and vaginal lesions: a combined analysis of three randomised clinical trials.

BACKGROUND: Vulval and vaginal cancers among younger women are often related to infection with human papillomavirus (HPV). These cancers are preceded by high-grade vulval intraepithelial neoplasia (VIN2-3) and vaginal intraepithelial neoplasia (VaIN2-3). Our aim was to do a combined analysis of three randomised clinical trials to assess the effect of a prophylactic quadrivalent HPV vaccine on the incidence of these diseases. METHODS: 18 174 women (16-26 years) were enrolled and randomised to receive either quadrivalent HPV6/11/16/18 L1 virus-like-particle vaccine or placebo at day 1, and months 2 and 6. Individuals underwent detailed anogenital examination at day 1, 1 month after dose three, and at 6-12-month intervals for up to 48 months. Suspect genital lesions were biopsied and read by a panel of pathologists and vaccine HPV type-specific DNA testing was done. The primary endpoint was the combined incidence of VIN2-3 or VaIN2-3 associated with HPV16 or HPV18. Primary efficacy analyses were done in a per-protocol population. FINDINGS: The mean follow-up time was 3 years. Among women naive to HPV16 or HPV18 through 1 month after dose three (per-protocol population; vaccine n=7811; placebo n=7785), the vaccine was 100% effective (95% CI 72-100) against VIN2-3 or VaIN2-3 associated with HPV16 or HPV18. In the intention-to-treat population (which included 18 174 women who, at day 1, could have been infected with HPV16 or HPV18), vaccine efficacy against VIN2-3 or VaIN2-3 associated with HPV16 or HPV18 was 71% (37-88). The vaccine was 49% (18-69) effective against all VIN2-3 or VaIN2-3, irrespective of whether or not HPV DNA was detected in the lesion. The most common treatment-related adverse event was injection-site pain. INTERPRETATION: Prophylactic administration of quadrivalent HPV vaccine was effective in preventing high-grade vulval and vaginal lesions associated with HPV16 or HPV18 infection in women who were naive to these types before vaccination. With time, such vaccination could result in reduced rates of HPV-related vulval and vaginal cancers.