Dosimetric predictors of radiation-induced vaginal stenosis after pelvic radiation therapy for rectal and anal cancer Journal Article

Authors: Son, C. H; Law, E.; Oh, J. H.; Apte, A. P.; Yang, T. J.; Riedel, E.; Wu, A. J.; Deasy, J. O.; Goodman, K. A.
Article Title: Dosimetric predictors of radiation-induced vaginal stenosis after pelvic radiation therapy for rectal and anal cancer
Abstract: Purpose Although vaginal stenosis (VS) is a recognized toxicity in women who receive pelvic radiation therapy (RT), the relationship between RT dose and the volume and extent of toxicity has not been analyzed. We modeled this relationship to identify predictors of VS. Methods and Materials We evaluated 54 women, aged 29 to 78 years, who underwent pelvic RT for rectal or anal cancer during 2008 to 2011 and were enrolled in a prospective study evaluating vaginal dilator use. Maximum dilator size was measured before RT (baseline) and 1 month and 12 months after RT. Dilator use was initiated at 1 month. The difference (D) in dilator size before and after RT was recorded. Those with D ≤-1 were classified as having VS (n=35); those with D ≥0 were classified as having no VS (n=19 at 1 month). Dose-volume parameters were extracted, and the generalized equivalent uniform dose (gEUD) was used to build a predictive model. Results The mean vaginal doses were 50.0 Gy and 36.8 Gy for anal and rectal cancer patients, respectively. One month after RT, a gEUD model using a wide range of a values suggests that sparing of vaginal volume to a low dose may be important. When gEUD (a = -1) was <35 Gy and the mean vaginal dose was <43 Gy, severe VS was reduced (P=.02). A 1-year analysis suggests increasingly negative D values with increasing mean dose. However, patients with compliance <40% were more likely to have toxicity. Conclusions Vaginal stenosis is influenced by multiple RT dose-volume characteristics. Mean dose and gEUD constraints together may reduce the risk of severe VS. Patients receiving higher mean vaginal doses should have greater compliance with dilator therapy to minimize risk of toxicity. Further validation with independent datasets is needed. © 2015 Elsevier Inc. All rights reserved.
Keywords: adult; controlled study; treatment outcome; aged; middle aged; major clinical study; intensity modulated radiation therapy; cisplatin; fluorouracil; cancer combination chemotherapy; cancer patient; cancer radiotherapy; prospective study; etoposide; radiotherapy; radiation injury; disease severity; dosimetry; folinic acid; stenosis; patient compliance; patient treatment; toxicity; mitomycin; oxaliplatin; risk reduction; anus cancer; computer assisted radiotherapy; rectum cancer; radiation dose distribution; diseases; predictive value; device therapy; rectal cancer; predictive modeling; diagnostic test accuracy study; radiation-induced; dose-volume parameters; methods and materials; prognosis; human; female; priority journal; article; generalized equivalent uniform dose (geud); vaginal dilators; radiation induced vaginal stenosis; vaginal dilator; vaginal injury
Journal Title: International Journal of Radiation Oncology, Biology, Physics
Volume: 92
Issue: 3
ISSN: 0360-3016
Publisher: Elsevier Inc.  
Date Published: 2015-07-01
Start Page: 548
End Page: 554
Language: English
DOI: 10.1016/j.ijrobp.2015.02.029
PROVIDER: scopus
PUBMED: 25936810
PMCID: PMC4822494
Notes: Export Date: 2 July 2015 -- Source: Scopus
Citation Impact
MSK Authors
  1. Karyn A Goodman
    254 Goodman
  2. Abraham Jing-Ching Wu
    239 Wu
  3. Jung Hun Oh
    132 Oh
  4. Joseph Owen Deasy
    348 Deasy
  5. Christina Huijin Son
    9 Son
  6. T. Jonathan Yang
    81 Yang
  7. Aditya Apte
    133 Apte
  8. Ethel Beeling P Law
    20 Law