Pulsed-dose rate image-guided adaptive brachytherapy in cervical cancer: Dose-volume effect relationships for the rectum and bladder

Radiother Oncol. 2015 Aug;116(2):226-32. doi: 10.1016/j.radonc.2015.06.027. Epub 2015 Jul 8.


Purpose: To establish dose-volume effect correlations for late bladder and rectum side effects in patients treated for locally advanced cervical cancer with concomitant chemoradiation followed by pulsed-dose rate image-guided adaptive brachytherapy.

Material and methods: The dosimetric data, converted in 2 Gy equivalent, from 217 patients were confronted to late morbidity defined as any event lasting or occurring 90 days after treatment initiation. Toxicity was assessed using the CTC-AE 3.0. Probit analyses and Log rank tests were performed to assess relationships.

Results: One hundred and sixty-one urinary and 58 rectal events were reported, affecting 98 (45.1%) and 51 (23.5%) patients, respectively. Cumulative incidences for grade 2-4 bladder and rectal morbidity were 24.3% and 9.6% at 3 years, respectively. Significant relationships were observed between grade 2-4 and 3-4 events and D0.1cm(3) and D2 cm(3) for the bladder and between grade 1-4 and 2-4 event probability and rectal D2 cm(3). The effective doses for 10% grade 2-4 morbidity were 65.3 Gy (59.8-81.3), and 55.4 Gy (15.7-63.6), respectively, for the rectum and bladder. Without considering urinary and rectal incontinence, for which the pertinence of correlating them with D2 cm(3) is questionable, ED10 were 68.5 Gy (62.9-110.6) and 65.5 Gy (51.4-71.6 Gy). When sorting patients according to D2 cm(3) levels, patients with high D2 cm(3) had significantly lower morbidity free survival rates for grade 1-4 and 2-4 urinary and rectal morbidity.

Conclusion: Significant dose-volume effect relationships were demonstrated between the modern dosimetric parameters and the occurrence of late rectal and urinary morbidity in patients treated with pulsed-dose-rate brachytherapy. Further studies are required to refine these relationships according to clinical cofactors, such as comorbidities.

Keywords: Cervix cancer; Dose–volume parameters; Image-guided adaptive brachytherapy; Morbidity; Normal tissue complication probability.

MeSH terms

  • Adult
  • Aged
  • Brachytherapy / adverse effects
  • Brachytherapy / methods*
  • Female
  • Humans
  • Middle Aged
  • Radiotherapy Dosage
  • Radiotherapy, Image-Guided / methods*
  • Rectum / radiation effects*
  • Urinary Bladder / radiation effects*
  • Uterine Cervical Neoplasms / radiotherapy*