Qu Ang
Peking University Third Hospital, China
Title: Dosimetry and efficacy analysis of 125i radioactive seeds implantation for cervical cancer with pelvic recurrent after radiotherapy
Biography
Biography: Qu Ang
Abstract
Purpose: Pelvic recurrent aft er radiotherapy of cervical cancer was diffi cult to treat. Th e implantation of radioactive 125I seeds
was suitable for recurrent patients aft er radiotherapy. Th erefore, we evaluated the effi cacy of radioactive 125I seeds implantation
for pelvic recurrent cervical cancer aft er radiotherapy. Th e dosimetric parameters aff ecting outcome were further analyzed to
guidance therapy.
Methods: A retrospective analysis was made with pelvic recurrent cervical cancer aft er radiotherapy from July 2005 to October
2015 in our hospital with 125I seeds implantation, under ultrasound or CT guidance. Treatment planning was performed before
implantation to estimate the number, activity of the seeds. Th e seeds numbers ranged from 10-140 with a median numbers
of 62.5 and the activity of seeds ranged from 0.5-0.8 mCi with a median activity of 0.7 mCi. Dosimetric verifi cation was
performed using CT scan immediately aft er 125I seeds implantation. D90, D100, V100, V150and V200 was evaluated in postoperative
plan. Th e Kaplan-Meier method was used to calculate the local progression free survival (LPFS) rate and overall survival (OS)
rate. Th e Log-rank test and Cox regression were used for univariate and multivariate analysis.
Results: All of the 36 patients received pelvic radiotherapy previously, 13.88%(5/36) of the patients received re-irradiation.
Th e median dose of cumulative radiotherapy was 56 (42-107) Gy EQD2. Th e interval time of the last radiotherapy to 125I
implantation was 12 (2-60) months. 15 cases were central recurrence (41.67%, 15/36), and 21 cases were pelvic wall recurrence
(58.33%, 21/36). Th e median follow-up time was 11.5 months (2-30 months). Vaginal fi stula occurred in 1 case. No other
severe adverse eff ects. Th e downgrade rate of pain was 79.2% (19/24). Th e short-term local control rate was 88.9% (32/36).
1-year and 2-year local progression-free survival (LPFS) rate were 34.9% and 20%, respectively. 1-year and 2-year OS rate
were 52% and 19.6%, respectively. Multivariate analysis showed that the location of the recurrence volume of lesion and D90
was signifi cantly related to LPFS (P<0.05). And the location of the recurrence was also signifi cantly related to OS (P<0.05).
33 cases were entered in dosimetric analysis. D90 was 128.5±47.4 Gy, D100 was 50.4±23.7 Gy, and V100 was 86.7%±12.9%.
Univariate analysis showed that D100, D90, V100 were signifi cantly associated with LPFS (P<0.05). D90>105 Gy and <105 Gy,
1-year LPFS were 53.3% and 0% (P<0.05), respectively. D100>55 Gy and <55 Gy, 1-year LPFS were 49.2% and 15.8% (P<0.05),
respectively. V100>91% and <91%, 1-year LPFS were 55% and 15.6% (P<0.05), respectively. Multivariate analysis showed D100
was the independent factors.
Conclusions: Radioactive 125I seeds implantation was a safe, eff ective salvage treatment for pelvic recurrent cervical cancer
aft er radiotherapy. It could relieve the pain for patients undergone multiple treatment aft er relapse. 125I radioactive seed
implantation was recommended for patients with recurrent in pelvic wall, compared with recurrent in central pelvic. D100>55Gy
or D90>105Gy or V100>91% could signifi cantly improve the local control.