PURPOSE: Radiation therapy is the standard management for locally advanced cervical @entity5 , but it has not yielded fully satisfactory results; a relatively high incidence of local failure remains. Standard radiation therapy techniques combine external beam radiation and brachytherapy generating a homogeneously composite dose distribution covering the lateral parametria but may not be adequate in the uterosacral and perirectal areas due to the spatial arrangement of intracavitary system and the constraints of rectal tolerance. We hypothesize that these dosimetric characteristics might lead to a higher incidence of central/marginal failures when the uterosacral space is involved by locally advanced @entity2622 . METHODS AND MATERIALS: Between January 1970 and December 1989, 343 @entity1 with clinical Stage IIIB cervical @entity5 were treated at the Mallinckrodt Institute of Radiology with radiation therapy alone. We identified 83 @entity1 with clinical evidence of @entity5 in the uterosacral region; the remaining 260 @entity1 either did not have uterosacral involvement or were unspecified. The dose of external beam irradiation ranged from 18.02 to 33.20 Gy to the central pelvis and 48.22 to 59.40 Gy to the lateral parametrium. The average total dose, including brachytherapy contribution, to point A and the lateral pelvis was 80.30 to 86.46 Gy and 60.50 to 73.40 Gy, respectively. External beam dose to the lateral parametria was, on average, 10 Gy higher in @entity1 with uterosacral involvement. RESULTS: We categorized the patterns of pelvic failure into central/marginal (including medial parametrium) and lateral parametria. The cumulative incidence of central/marginal failure at 5 years was significantly higher in the group of @entity1 with uterosacral involvement (36% compared with 21% for @entity1 without uterosacral involvement or unspecified) (p = 0.002). Lateral parametrial failure was similar for @entity1 with and without uterosacral involvement (39% and 38% at 5 years, respectively) (p = 0.42). The actuarial incidence of distant @entity3 was identical in the two groups: 46% at 5 years. Multivariate analysis confirmed that uterosacral space involvement increased the risk of pelvic recurrence (p = 0.044) and was the most significant factor that influenced the central/marginal pelvic failure (p = 0.002). CONCLUSIONS: Uterosacral involvement by locally advanced @entity2622 significantly increased overall pelvic failure and was the most significant prognosticator of central/marginal pelvic failure. This is the result of the spatial constraints of the standard intracavitary geometry that deliver inadequate dose posteriorly to encompass the uterosacral space. Plausible ways to compensate the underdose in the uterosacral space include increasing whole pelvis dose without compromising the intracavitary brachytherapy dose, using a supplemental interstitial implant or adding a posterior oblique external beam boost.

Uterosacral space involvement in locally advanced XXXX .

@entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'cancer'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity2622 :: ('MESH:D002583', 'Disease') :: ['carcinoma of uterine cervix', 'carcinoma of the uterine cervix'] @entity3 :: ('MESH:D009362', 'Disease') :: ['metastasis']
@entity2622 :: (MESH:D002583,Disease) :: ['carcinoma of the uterine cervix']
