Simultaneously integrated boost (SIB) spares OAR and reduces treatment time in locally advanced cervical cancer.
We performed a dosimetric comparison of sequential IMRT (sIMRT) and simul-taneously integrated boost (SIB) IMRT to boost PET-avid lymph nodes while concurrently treating pelvic targets to determine the potential of SIB IMRT to reduce overall treatment duration in locally advanced cervical cancer. Ten patients receiving definitive radiation therapy were identified retrospectively. RTOG consensus guidelines were followed to delineate the clinical target volume and organs at risk (OAR), which were then expanded per IMRT consortium guidelines to yield the planning target volume (PTV). Dosimetric parameters for PTVs and OAR including conformity (CI95%) were collected and compared using Wilcoxon signed-rank tests with Bonferroni correction. The median PTV volume was 1843 cc (1088-2225 cc) and the median boost volume was 43 cc (15-129 cc). Comparable target volume coverage was achieved with sIMRT and SIB plans, while hot spots were significantly reduced using SIB. SIB plans improved sparing for all OAR, though only rectum and small bowel doses were statistically significant. Comparing sIMRT and SIB plans averaged over all patients, rectal doses were V45: 70.8% vs. 64.5% (p = 0.002) and 0.1 cc: 50.7 Gy vs. 48.7 Gy (p = 0.006). For small bowel, sIMRT and SIB IMRT plans yielded V45: 13.4% vs. 11.4% (p = 0.006) and 1 cc: 54.4 Gy vs. 52.6 Gy (p = 0.006), respectively. Doses to femoral heads and blad-der trended towards significance in favor of SIB plans. The mean treatment time was 25 versus 29 days for SIB and sIMRT plans, respectively. When compared to sIMRT, SIB for treatment of nodal targets provides a significant, but small, dose reduction (3.8%-4.4%) to OAR, which leads to comparable biological dose despite higher fractional doses. Furthermore, SIB IMRT reduces overall treatment time and simplifies the planning process, and should be considered for targeting PET-positive nodal disease in patients with locally advanced cervical cancer.
The University of Chicago. 123@123.com.
Christine H
CH
Feng
Yasmin
Y
Hasan
Malgorzata
M
Kopec
Hania A
HA
Al-Hallaq
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D010347:Patient Care Planning; D010388:Pelvis / Q000528:radiation effects; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012007:Rectum / Q000528:radiation effects; D012189:Retrospective Studies; D002583:Uterine Cervical Neoplasms / Q000532:radiotherapy*
Radiat Oncol. 2013 Jan 03;8:5
23286694
Int J Radiat Oncol Biol Phys. 2003 Dec 1;57(5):1480-91
14630288
Brachytherapy. 2012 Jan-Feb;11(1):33-46
22265436
Int J Radiat Oncol Biol Phys. 2013 Jul 1;86(3):562-8
23561652
Int J Radiat Oncol Biol Phys. 2005 Jul 1;62(3):933-9
15936580
Int J Radiat Oncol Biol Phys. 2004 Mar 15;58(4):1289-97
15001274
Int J Radiat Oncol Biol Phys. 2003 Aug 1;56(5):1354-60
12873680
Int J Radiat Oncol Biol Phys. 2002 Jan 1;52(1):33-48
11777620
Int J Radiat Oncol Biol Phys. 2011 Feb 1;79(2):348-55
20472347
Cancer. 2013 Jan 15;119(2):325-31
22806897
Int J Radiat Oncol Biol Phys. 2014 Dec 1;90(5):1091-8
25303889
Int J Radiat Oncol Biol Phys. 2014 Feb 1;88(2):357-62
24411609
N Engl J Med. 1999 Apr 15;340(15):1137-43
10202164
J Natl Compr Canc Netw. 2015 Apr;13(4):395-404; quiz 404
25870376
Int J Radiat Oncol Biol Phys. 2008 Aug 1;71(5):1504-10
18640499
Med Dosim. 2012 Autumn;37(3):310-3
22317848
Radiat Oncol. 2014 Mar 25;9:83
24661323
Int J Radiat Oncol Biol Phys. 1993 Feb 15;25(3):391-7
8436516
J Clin Oncol. 2008 Dec 10;26(35):5802-12
19001332
Int J Radiat Oncol Biol Phys. 2001 Sep 1;51(1):261-6
11516876
Int J Radiat Oncol Biol Phys. 2013 Apr 1;85(5):1262-8
23182395
Gynecol Oncol. 2003 Oct;91(1):39-45
14529660
Int J Radiat Oncol Biol Phys. 2005 Dec 1;63(5):1604-12
16198509