# Radiation Oncology/Vagina/Overview

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Vaginal Cancer Overview

## Epidemiology

* Majority of vaginal neoplasms are metastatic; typically by direct extension (vulva/cervix), lymphatics, or hematogenous spread.
* According to FIGO staging, if the tumor involves vulva or the cervical os, it is classified as arising from that structure, even if it is centered in vagina
* Only 10-20% are primary vaginal tumors, and account for ~2% of gynecologic malignancies
* Age:
** 75% in patients >50
** 60% in patients >70
* Location PMID 5162136 (1971):
** 58% tumors occur on posterior wall
** 51% tumors occur in upper 1/3 of vagina
* Approximately 60% have had prior hysterectomy for variety of reasons

## Anatomy

Vaginal Anatomy
* Introitus - vaginal opening
* Hymen - thin tissue membrane concealing vaginal canal. Formed by connection of the urogenital sinus epithelium invaginating inward, with the mullerian ducts descending from above
* Fornices - invaginations between walls of vagina and cervix
* Pouch of Douglas - retrouterine pouch separating vagina from rectum
* Average length 7.5 cm
* Vaginal wall
** Stratified squamous epithelium
** Muscularis layer
** Adventitia
Lymphatic drainage of vagina
* Complex
* Upper 2/3 of vagina - pelvic nodes (obturator, internal/external iliac)
* Lower 1/3 of vagina - inguinal and pelvic nodes
* 5-20% present with clinically positive nodes
* Torino, Italy; 2002 PMID 12210022 -- "Rationale and definition of the lateral extension of the inguinal lymphadenectomy for vulvar cancer derived from an embryological and anatomical study." (Micheletti L, J Surg Oncol. 2002 Sep;81(1):19-24.)
** Embryological and anatomic study to determine lateral extension of groin lymphadenectomy in vulvar cancer. 3 human fetuses, 1 patient dissected
** Outcome: Most lateral superficial inguinal lymph node does not rise above medial margin of the sartorius muscle, nor far lateral to where superficial circumflex iliac vessels cross the inguinal ligament
** Conclusion: Lateral surgical landmark established

## Risk Factors

* Approximately 2/3 are HPV-related
* HSV, trichomonas, number of sexual partners >5
* Long term pessary use, smoking, immunosuppression, pelvic radiation
* Maternal use of diethylstilbestrol (DES) during first 4 months in utero

## Associated with prior cervical carcinoma

* U. Michigan, 1982 - PMID 7095583 (No abstract) PDF -- "Neoplasms of the vagina following cervical carcinoma." (Choo YC, Gynecol Oncol. 1982 Aug;14(1):125-32.)

## Prevention & Screening

* Insufficient evidence for women s/p TAH
* Pap smear for high-risk populations; continue into older years

## Presentation

* Abnormal vaginal bleeding in 50-75%, discharge, pruritus
* Dysuria, pelvic pain in more advanced disease

## Work-Up

* Speculum examination, rotate to observe posterior wall
* Vaginal palpation, bimanual pelvic, rectovaginal for staging
* Evaluate vulva and cervical os for disease - biopsy suspicious lesions
* Evaluate for mets with CXR, CBC, LFTs and alk phos
* Biopsy suspicious inguinal nodes
* Stage II or greater consider cystoscopy and/or sigmoidoscopy
* Consider MRI - superior to CT for evaluation of soft tissue extension (though neither may be used in clinical staging)
** Consider dynamic contrast MRI
* Manchester; 2007 (UK)(1996-2005) PMID 17467392 -- "Magnetic resonance imaging of primary vaginal carcinoma." (Taylor MB, Clin Radiol. 2007 Jun;62(6):549-55.)
** Retrospective. 25 patients with MRI examination. Isointense to muscle on T1, hyperintense on T2
** Outcome: 88% extension beyond vagina, 56% Stage III/IV
** Conclusion: MRI identified >95% tumors, radiological staging correlated with outcome, and provided treatment planning information

## Histology

* Squamous cell carcinoma (80-90%), primarily in older patients, invade locally with mets to lung and liver
* Melanoma (3-5%), second most common cancer in vagina
* Clear cell carcinoma, particularly in young women with DES exposure in utero (FDA advised against DES use in 1971 - thus incidence has dropped dramatically)
* Rhabdomyosarcoma (botryoid type) most common in children
* Verrucous carcinoma (rare) - tend to recur locally and rarely metastasize thus surgical approaches may be appropriate PMID 635607

## Prognostic Factors

* Clinical stage most important
* Adenocarcinoma and non-epithelial tumors (melanoma, sarcoma) worse than squamous cell