General Information About Vulvar Cancer
Incidence and Mortality
Vulvar cancer accounts for about 5% of cancers of the female genital system in the United States.
Estimated new cases and deaths from vulvar cancer in the United States in 2018:
- New cases: 6,190.
- Deaths: 1,200.
The vulva is the area immediately external to the vagina, including the mons pubis, labia, clitoris, Bartholin glands, and perineum. The labia majora are the most common site of vulvar carcinoma involvement and account for about 50% of cases. The labia minora account for 15% to 20% of vulvar carcinoma cases. The clitoris and Bartholin glands are less frequently involved. Lesions are multifocal in about 5% of cases. About 90% of vulvar carcinomas are squamous cell cancers. This evidence summary covers squamous cell cancers and vulvar intraepithelial neoplasias (VIN), some of which are thought to be precursors to invasive squamous cell cancers.
Survival is dependent on the pathologic status of the inguinal nodes and whether spread to adjacent structures has occurred. The size of the primary tumor is less important in defining prognosis. In patients with operable disease without nodal involvement, the overall survival (OS) rate is 90%; however, in patients with nodal involvement, the 5-year OS rate is approximately 50% to 60%.
Risk factors for lymph node metastasis include the following:[5-9]
- Clinical node status.
- Degree of differentiation.
- Tumor stage.
- Tumor thickness.
- Depth of stromal invasion.
- Presence of capillary-lymphatic space invasion.
Overall, about 30% of patients with operable disease have lymph nodal spread.
Other risk factors
In many cases, the development of vulvar cancer is preceded by condyloma or squamous dysplasia. The prevailing evidence favors human papillomavirus (HPV) as a causative factor in many genital tract carcinomas. The HPV-related basaloid and warty types are associated with VIN. About 75% to 100% of basaloid and warty carcinomas harbor HPV infection. In addition to the much higher prevalence of HPV in these subtypes than in the keratinizing subtypes, the basaloid and warty subtypes also share many common risk factors with cervical cancers, including multiplicity of sex partners, early age at initiation of sexual intercourse, and history of abnormal Pap smears. HPV-associated VIN (termed usual-type VIN when high-grade 2 and 3) is most common in women younger than 50 years, whereas non-HPV VIN (termed differentiated-type VIN when high-grade 3) is most common in older women. The former lesion-type VIN grade 1 is no longer classified as a true VIN.[12,13]
The pattern of spread is influenced by the histology. Well-differentiated lesions tend to spread along the surface with minimal invasion, whereas anaplastic lesions are more likely to be deeply invasive. Spread beyond the vulva is either to adjacent organs such as the vagina, urethra, and anus, or via the lymphatics to the inguinal and femoral lymph nodes, followed by the deep pelvic nodes. Hematogenous spread appears to be uncommon.
- American Cancer Society: Cancer Facts and Figures 2018. Atlanta, Ga: American Cancer Society, 2018. Available online. Last accessed August 3, 2018.
- Macnab JC, Walkinshaw SA, Cordiner JW, et al.: Human papillomavirus in clinically and histologically normal tissue of patients with genital cancer. N Engl J Med 315 (17): 1052-8, 1986. [PUBMED Abstract]
- Eifel PJ, Berek JS, Markman MA: Cancer of the cervix, vagina, and vulva. In: DeVita VT Jr, Lawrence TS, Rosenberg SA: Cancer: Principles and Practice of Oncology. 9th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2011, pp 1311-44.
- Vulva. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 379-81.
- Homesley HD, Bundy BN, Sedlis A, et al.: Assessment of current International Federation of Gynecology and Obstetrics staging of vulvar carcinoma relative to prognostic factors for survival (a Gynecologic Oncology Group study). Am J Obstet Gynecol 164 (4): 997-1003; discussion 1003-4, 1991. [PUBMED Abstract]
- Boyce J, Fruchter RG, Kasambilides E, et al.: Prognostic factors in carcinoma of the vulva. Gynecol Oncol 20 (3): 364-77, 1985. [PUBMED Abstract]
- Sedlis A, Homesley H, Bundy BN, et al.: Positive groin lymph nodes in superficial squamous cell vulvar cancer. A Gynecologic Oncology Group Study. Am J Obstet Gynecol 156 (5): 1159-64, 1987. [PUBMED Abstract]
- Binder SW, Huang I, Fu YS, et al.: Risk factors for the development of lymph node metastasis in vulvar squamous cell carcinoma. Gynecol Oncol 37 (1): 9-16, 1990. [PUBMED Abstract]
- Homesley HD, Bundy BN, Sedlis A, et al.: Prognostic factors for groin node metastasis in squamous cell carcinoma of the vulva (a Gynecologic Oncology Group study) Gynecol Oncol 49 (3): 279-83, 1993. [PUBMED Abstract]
- Hampl M, Sarajuuri H, Wentzensen N, et al.: Effect of human papillomavirus vaccines on vulvar, vaginal, and anal intraepithelial lesions and vulvar cancer. Obstet Gynecol 108 (6): 1361-8, 2006. [PUBMED Abstract]
- Schiffman M, Kjaer SK: Chapter 2: Natural history of anogenital human papillomavirus infection and neoplasia. J Natl Cancer Inst Monogr (31): 14-9, 2003. [PUBMED Abstract]
- Pepas L, Kaushik S, Bryant A, et al.: Medical interventions for high grade vulval intraepithelial neoplasia. Cochrane Database Syst Rev (4): CD007924, 2011. [PUBMED Abstract]
- Sideri M, Jones RW, Wilkinson EJ, et al.: Squamous vulvar intraepithelial neoplasia: 2004 modified terminology, ISSVD Vulvar Oncology Subcommittee. J Reprod Med 50 (11): 807-10, 2005. [PUBMED Abstract]