TY - JOUR
T1 - Dosimetric parameters that predict late rectal complications after curative radiotherapy in patients with uterine cervical carcinoma
AU - Kim, Tae Hyun
AU - Choi, Jinho
AU - Park, Sung Yong
AU - Lee, Seok Ho
AU - Lee, Kyu Chan
AU - Yang, Dae Sik
AU - Shin, Kyung Hwan
AU - Cho, Kwan Ho
AU - Lim, Hyun Sun
AU - Kim, Joo Young
PY - 2005/9/15
Y1 - 2005/9/15
N2 - BACKGROUND. Late rectal complication (LRC) was a major late complication in patients with uterine cervical carcinoma who were treated with a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary irradiation (HDR-ICR). For the current study, the authors retrospectively evaluated dosimetric parameters that were correlated with LRC ≥ Grade 2 in patients with uterine cervical carcinoma who were treated with curative radiotherapy, and they analyzed the appropriate dose estimates to the rectum that were predictive for LRC ≥ Grade 2. METHODS. Between July, 1994 and September, 2002, 157 patients who were diagnosed with Stage IB-IIIB cervical carcinoma and were treated with definitive radiotherapy were included. EBRT (41.4-66 grays [Gy] in 23-33 fractions) to the whole pelvis was delivered to all patients, with midline shielding performed after a 36-50.4 Gy external dose. HDR-ICR (21-39 Gy in 6-13 fractions to Point A) was administered at a rate of 2 fractions weekly after midline shielding of EBRT. LRC was scored using Radiation Therapy Oncology Group criteria. The total biologically effective dose (BED) at specific points, such as Point A (BEDPoint A), rectal point (BEDRP), and maximal rectal point (BEDMP), was determined by a summation of the EBRT and HDR-ICR components, in which the α/β ratio was set to 3. Analyzed parameters included patient age, tumor size, stage, concurrent chemotherapy, ICR fraction size, RP ratio (dose at the rectal point according to the Point A dose), MP ratio (dose at the maximal rectal point according to the Point A dose), EBRT dose, BEDPoint A, BEDRP, and BEDMP. RESULTS. The 5-year actuarial overall rate of LRC ≥ Grade 2 in all patients was 18.4%. Univariate analysis showed that the RP ratio, MP ratio, EBRT dose, BEDpoint A, BEDRP, and BEDMP were correlated with LRC ≥ Grade 2 (P < 0.05). Multivariate analysis showed that, of all clinical and dosimetric parameters evaluated, only BEDRP was correlated with LRC ≥ Grade 2(P = 0.009). The 5-year actuarial rate of LRC ≥ Grade 2 was 5.4% in patients with a BEDRP < 125 Gy 3 and 36.1% in patients with a BEDRP ≥ 125 Gy 3 (P < 0.001). CONCLUSIONS. BEDRP was a useful dosimetric parameter for predicting the risk of LRC ≥ Grade 2 and should be limited to < 125 Gy3 whenever possible to minimize the risk of LRC ≥ Grade 2 in patients with uterine cervical carcinoma who are treated with a combination of EBRT and HDR-ICR.
AB - BACKGROUND. Late rectal complication (LRC) was a major late complication in patients with uterine cervical carcinoma who were treated with a combination of external beam radiotherapy (EBRT) and high-dose-rate intracavitary irradiation (HDR-ICR). For the current study, the authors retrospectively evaluated dosimetric parameters that were correlated with LRC ≥ Grade 2 in patients with uterine cervical carcinoma who were treated with curative radiotherapy, and they analyzed the appropriate dose estimates to the rectum that were predictive for LRC ≥ Grade 2. METHODS. Between July, 1994 and September, 2002, 157 patients who were diagnosed with Stage IB-IIIB cervical carcinoma and were treated with definitive radiotherapy were included. EBRT (41.4-66 grays [Gy] in 23-33 fractions) to the whole pelvis was delivered to all patients, with midline shielding performed after a 36-50.4 Gy external dose. HDR-ICR (21-39 Gy in 6-13 fractions to Point A) was administered at a rate of 2 fractions weekly after midline shielding of EBRT. LRC was scored using Radiation Therapy Oncology Group criteria. The total biologically effective dose (BED) at specific points, such as Point A (BEDPoint A), rectal point (BEDRP), and maximal rectal point (BEDMP), was determined by a summation of the EBRT and HDR-ICR components, in which the α/β ratio was set to 3. Analyzed parameters included patient age, tumor size, stage, concurrent chemotherapy, ICR fraction size, RP ratio (dose at the rectal point according to the Point A dose), MP ratio (dose at the maximal rectal point according to the Point A dose), EBRT dose, BEDPoint A, BEDRP, and BEDMP. RESULTS. The 5-year actuarial overall rate of LRC ≥ Grade 2 in all patients was 18.4%. Univariate analysis showed that the RP ratio, MP ratio, EBRT dose, BEDpoint A, BEDRP, and BEDMP were correlated with LRC ≥ Grade 2 (P < 0.05). Multivariate analysis showed that, of all clinical and dosimetric parameters evaluated, only BEDRP was correlated with LRC ≥ Grade 2(P = 0.009). The 5-year actuarial rate of LRC ≥ Grade 2 was 5.4% in patients with a BEDRP < 125 Gy 3 and 36.1% in patients with a BEDRP ≥ 125 Gy 3 (P < 0.001). CONCLUSIONS. BEDRP was a useful dosimetric parameter for predicting the risk of LRC ≥ Grade 2 and should be limited to < 125 Gy3 whenever possible to minimize the risk of LRC ≥ Grade 2 in patients with uterine cervical carcinoma who are treated with a combination of EBRT and HDR-ICR.
KW - Dosimetric parameter
KW - High-dose-rate intracavitary irradiation
KW - Late rectal complication
KW - Uterine cervical carcinoma
UR - http://www.scopus.com/inward/record.url?scp=24644498968&partnerID=8YFLogxK
U2 - 10.1002/cncr.21292
DO - 10.1002/cncr.21292
M3 - Article
C2 - 16078262
AN - SCOPUS:24644498968
SN - 0008-543X
VL - 104
SP - 1304
EP - 1311
JO - Cancer
JF - Cancer
IS - 6
ER -