- Email: [email protected]
2343
Proceedings of the 48th Annual ASTRO Meeting
Conclusions: Our study shows that when the STP approach is used, a significantly higher dose is delivered to point A and ICRU 38 rectal and bladder points. Although STP may save valuable planning time, if unavoidable, it must be used cautiously. Author Disclosure: H. Patone, None; L. Souhami, None; W. Parker, None; F. Cury, None; L. Portelance, None.
2343
Intracavitary Cervical Brachytherapy With a Rectal Tandem Balloon (RTB): Analysis of Clinical and Dosimetric Endpoints
L. Tuanquin1, B. Plants1, J. Williams2, C. Welch2, D. Mihailidis1, M. Schiano2, P. Raja1, L. Whaley1, M. Harmon1 Charleston Radiation Therapy Consultants, PLLC., Charleston, WV, 2West Virginia University’s Robert C. Byrd Health Sciences Center, Charleston, WV
1
Purpose/Objective(s): To determine the effects of a rectal tandem balloon (RTB) used during intracavitary brachytherapy (ICB) on rectal point dose and clinical toxicity. Materials/Methods: Retrospective review was done of all patients treated with a RTB during high-dose-rate (HDR) ICB for cervical cancer at CRTC from 1/99 to 12/05. Women received cisplatin-based chemotherapy, external radiation (ERT) to the pelvis, and HDR ICB. The RTB (a balloon catheter) was placed over a standard Fletcher tandem and adjacent to the cervix. A ring was fixed to the tandem, gauze and a custom fixation device were placed, and the RTB was inflated with 20 –30 cc of contrast to displace the rectum. Orthogonal films were taken, ICRU 38 points were used, and dosimetric & clinical endpoints were analyzed. Doses were compared with the RTB in deflated and inflated positions. Results: Since 1999, 123 patients received HDR ICB with the RTB technique; 23 patients with uterine cancer and 4 patients with stage IV disease were excluded. The remaining 96 cervical cancer patients received 604 HDR insertions. The mean dose of ERT was 4454 cGy (2000 –5040 cGy). Midline block was used in 55.5% and paraaortic boost in 5 patients. Mean total dose to point A was 7703 cGy (6270 –9100 cGy). Mean ICB dose to point A was 3789 cGy (1800 –5400 cGy) in 1–9 fractions (mean 6). Mean dose per fraction was 592 cGy (400 – 800 cGy). Mean rectal and bladder point doses were 293 cGy (127– 451 cGy) and 340 cGy (166 – 601 cGy), respectively. For 57 insertions with the RTB in the inflated and deflated positions, mean bladder point dose was 316 cGy (96 – 609 cGy), and 314 cGy (94 – 608 cGy), respectively. Mean rectal point dose with inflation and deflation was 252 cGy (50 – 432 cGy), and 289 cGy (55– 697 cGy), respectively. Mean percent change in bladder and rectal point dose from inflation was 0.9% (-8.6% to 14.1%) and -9.7% (-45.8% to 12.0%), respectively (Fig. 1). A decrease in rectal dose was seen in 81% of patients. After a median follow-up of 17 months (2–77 months), 19 of 101 patients had recurrence (8 local and 11 distant). 2-yr LC and OS were 91.7% and 75.2%, respectively. 2-yr OS for stage II and III were 84.3% and 58.4%, respectively. The overall grade 3– 4 GI & GU toxicity were both 10%. There were no treatment deaths. Conclusions: The use of a rectal tandem balloon in HDR ICB allows decreased dose to the ICRU rectal point and a low rate of toxicity without compromising tumor control. A deflated RTB during insertion minimizes discomfort in women with narrow vaginal vaults and may be useful in CT-based ICB with devices lacking internal shielding.
Author Disclosure: L. Tuanquin, None; B. Plants, None; J. Williams, None; C. Welch, None; D. Mihailidis, None; M. Schiano, None; P. Raja, None; L. Whaley, None; M. Harmon, None.
2344
Inadequate Coverage of Iliac Nodes With Conventional, Non-CT Planning of Endometrial Cancer RT 1
J. N. Shah , F. Trichter2, S. Bhatia2, R. D. Ennis2 Columbia University Medical Center, New York, NY, 2St. Luke’s-Roosevelt Hospital Center, Continuum Health Partners, New York, NY
1
Purpose/Objective(s): We present the first reported (to our knowledge) volumetric dosimetric analysis that examines if conventional pelvic RT fields for endometrial cancer, designed without CT-based iliac vessel location, provide adequate coverage of iliac lymph nodes. Materials/Methods: 11 consecutive patients underwent simulation CT scanning for endometrial cancer RT in this pilot study. Before using CT data, a conventional (“CONV”) four-field pelvic setup (anteroposterior, AP; posteroanterior, PA; right/left laterals) was designed for each patient. Field borders were standard: superiorly, L5-S1; inferiorly, bottom of obturator foramina; laterally on AP/PA fields, 2 cm beyond pelvic brim; anteriorly/posteriorly on lateral fields, pubic symphysis front edge/S2-S3.
S401
Conclusions: Our study shows that when the STP approach is used, a significantly higher dose is delivered to point A and ICRU 38 rectal and bladder points. Although STP may save valuable planning time, if unavoidable, it must be used cautiously. Author Disclosure: H. Patone, None; L. Souhami, None; W. Parker, None; F. Cury, None; L. Portelance, None.
2343
Intracavitary Cervical Brachytherapy With a Rectal Tandem Balloon (RTB): Analysis of Clinical and Dosimetric Endpoints
L. Tuanquin1, B. Plants1, J. Williams2, C. Welch2, D. Mihailidis1, M. Schiano2, P. Raja1, L. Whaley1, M. Harmon1 Charleston Radiation Therapy Consultants, PLLC., Charleston, WV, 2West Virginia University’s Robert C. Byrd Health Sciences Center, Charleston, WV
1
Purpose/Objective(s): To determine the effects of a rectal tandem balloon (RTB) used during intracavitary brachytherapy (ICB) on rectal point dose and clinical toxicity. Materials/Methods: Retrospective review was done of all patients treated with a RTB during high-dose-rate (HDR) ICB for cervical cancer at CRTC from 1/99 to 12/05. Women received cisplatin-based chemotherapy, external radiation (ERT) to the pelvis, and HDR ICB. The RTB (a balloon catheter) was placed over a standard Fletcher tandem and adjacent to the cervix. A ring was fixed to the tandem, gauze and a custom fixation device were placed, and the RTB was inflated with 20 –30 cc of contrast to displace the rectum. Orthogonal films were taken, ICRU 38 points were used, and dosimetric & clinical endpoints were analyzed. Doses were compared with the RTB in deflated and inflated positions. Results: Since 1999, 123 patients received HDR ICB with the RTB technique; 23 patients with uterine cancer and 4 patients with stage IV disease were excluded. The remaining 96 cervical cancer patients received 604 HDR insertions. The mean dose of ERT was 4454 cGy (2000 –5040 cGy). Midline block was used in 55.5% and paraaortic boost in 5 patients. Mean total dose to point A was 7703 cGy (6270 –9100 cGy). Mean ICB dose to point A was 3789 cGy (1800 –5400 cGy) in 1–9 fractions (mean 6). Mean dose per fraction was 592 cGy (400 – 800 cGy). Mean rectal and bladder point doses were 293 cGy (127– 451 cGy) and 340 cGy (166 – 601 cGy), respectively. For 57 insertions with the RTB in the inflated and deflated positions, mean bladder point dose was 316 cGy (96 – 609 cGy), and 314 cGy (94 – 608 cGy), respectively. Mean rectal point dose with inflation and deflation was 252 cGy (50 – 432 cGy), and 289 cGy (55– 697 cGy), respectively. Mean percent change in bladder and rectal point dose from inflation was 0.9% (-8.6% to 14.1%) and -9.7% (-45.8% to 12.0%), respectively (Fig. 1). A decrease in rectal dose was seen in 81% of patients. After a median follow-up of 17 months (2–77 months), 19 of 101 patients had recurrence (8 local and 11 distant). 2-yr LC and OS were 91.7% and 75.2%, respectively. 2-yr OS for stage II and III were 84.3% and 58.4%, respectively. The overall grade 3– 4 GI & GU toxicity were both 10%. There were no treatment deaths. Conclusions: The use of a rectal tandem balloon in HDR ICB allows decreased dose to the ICRU rectal point and a low rate of toxicity without compromising tumor control. A deflated RTB during insertion minimizes discomfort in women with narrow vaginal vaults and may be useful in CT-based ICB with devices lacking internal shielding.
Author Disclosure: L. Tuanquin, None; B. Plants, None; J. Williams, None; C. Welch, None; D. Mihailidis, None; M. Schiano, None; P. Raja, None; L. Whaley, None; M. Harmon, None.
2344
Inadequate Coverage of Iliac Nodes With Conventional, Non-CT Planning of Endometrial Cancer RT 1
J. N. Shah , F. Trichter2, S. Bhatia2, R. D. Ennis2 Columbia University Medical Center, New York, NY, 2St. Luke’s-Roosevelt Hospital Center, Continuum Health Partners, New York, NY
1
Purpose/Objective(s): We present the first reported (to our knowledge) volumetric dosimetric analysis that examines if conventional pelvic RT fields for endometrial cancer, designed without CT-based iliac vessel location, provide adequate coverage of iliac lymph nodes. Materials/Methods: 11 consecutive patients underwent simulation CT scanning for endometrial cancer RT in this pilot study. Before using CT data, a conventional (“CONV”) four-field pelvic setup (anteroposterior, AP; posteroanterior, PA; right/left laterals) was designed for each patient. Field borders were standard: superiorly, L5-S1; inferiorly, bottom of obturator foramina; laterally on AP/PA fields, 2 cm beyond pelvic brim; anteriorly/posteriorly on lateral fields, pubic symphysis front edge/S2-S3.
S401