Correlation of traditional point a with anatomic location of uterine artery and ureter in cancer of the uterine cervix.
OBJECTIVE
Point A, used for dose specification for intracavitary brachytherapy for cervical cancer, is the point at which the uterine artery and ureter cross. This study assessed compatibility of commonly used traditional point A (TPA) and actual anatomic point A (APA).


METHODS
We visualized and placed radiopaque clips at the APA during pelvic and paraaortic lymphadenectomy in 11 patients with cervical carcinoma. Orthogonal and oblique radiographs were obtained after insertion of brachytherapy applicators. We measured the distance between the TPA and APA and estimated the brachytherapy dose to each of the two points.


RESULTS
A total of 64 brachytherapy treatments were performed. The mean distances between the TPA and APA were 5.2 +/- 1.0 cm on the right and 5.4 +/- 1.1 cm on the left. The estimated brachytherapy doses delivered to the APA as a percentage of the presumed 500-cGy fraction size to the TPA were 35.2% (176.6 +/- 59.0 cGy) on the right and 30.0% (150.2 +/- 42.9 cGy) on the left. The marked discrepancy in the position of the two points was not related to individual kinetic variations during brachytherapy treatment, tumor size, or bladder filling.


CONCLUSIONS
The conventional TPA does not provide an accurate estimate of the APA determined during lymphadenectomy, indicating a need to reevaluate the current practice for determining the brachytherapy prescription for cervical cancer. (ClinicalTrials.gov Identifier, NCT00319462).
Wang
Kung-Liahng
KL
Department of Obstetrics and Gynecology, Mackay Memorial Hospital, Taipei, Taiwan.
Yang
Yuh-Cheng
YC
Chao
K S Clifford
KS
Wu
Meng-Hao
MH
Tai
Hung-Chi
HC
Chen
Tze-Chien
TC
Huang
Ming-Chao
MC
Chen
Jen-Ruei
JR
Su
Tsung-Hsien
TH
Chen
Yu-Jen
YJ
D000328:Adult; D000792:Angiography; D001158:Arteries / Q000033:anatomy & histology; D001918:Brachytherapy / Q000379:methods*; D002584:Cervix Uteri / Q000098:blood supply; D005260:Female; D006801:Humans; D007813:Laparotomy / Q000379:methods; D008197:Lymph Node Excision; D008875:Middle Aged; D011446:Prospective Studies; D019736:Prostheses and Implants; D014513:Ureter / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D001743:Urinary Bladder; D002583:Uterine Cervical Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D014599:Uterus / Q000098:blood supply*