Radiation Oncology/Vagina/Overview

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