Prospective study of functional bone marrow-sparing intensity modulated radiation therapy with concurrent chemotherapy for pelvic malignancies.
OBJECTIVE
To test the hypothesis that intensity modulated radiation therapy (IMRT) can reduce radiation dose to functional bone marrow (BM) in patients with pelvic malignancies (phase IA) and estimate the clinical feasibility and acute toxicity associated with this technique (phase IB).


METHODS
We enrolled 31 subjects (19 with gynecologic cancer and 12 with anal cancer) in an institutional review board-approved prospective trial (6 in the pilot study, 10 in phase IA, and 15 in phase IB). The mean age was 52 years; 8 of 31 patients (26%) were men. Twenty-one subjects completed (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) simulation and magnetic resonance imaging by use of quantitative IDEAL (IDEAL IQ; GE Healthcare, Waukesha, WI). The PET/CT and IDEAL IQ were registered, and BM subvolumes were segmented above the mean standardized uptake value and below the mean fat fraction within the pelvis and lumbar spine; their intersection was designated as functional BM for IMRT planning. Functional BM-sparing vs total BM-sparing IMRT plans were compared in 12 subjects; 10 were treated with functional BM-sparing pelvic IMRT per protocol.


RESULTS
In gynecologic cancer patients, the mean functional BM V(10) (volume receiving ≥10 Gy) and V(20) (volume receiving ≥20 Gy) were 85% vs 94% (P<.0001) and 70% vs 82% (P<.0001), respectively, for functional BM-sparing IMRT vs total BM-sparing IMRT. In anal cancer patients, the corresponding values were 75% vs 77% (P=.06) and 62% vs 67% (P=.002), respectively. Of 10 subjects treated with functional BM-sparing pelvic IMRT, 3 (30%) had acute grade 3 hematologic toxicity or greater.


CONCLUSIONS
IMRT can reduce dose to BM subregions identified by (18)F-fluorodeoxyglucose-PET/CT and IDEAL IQ. The efficacy of BM-sparing IMRT is being tested in a phase II trial.
Department of Radiation Oncology, and Center for Advanced Radiotherapy Technologies, University of California, San Diego, La Jolla, California 92093, USA.
Yun
Y
Liang
Mark
M
Bydder
Catheryn M
CM
Yashar
Brent S
BS
Rose
Mariel
M
Cornell
Carl K
CK
Hoh
Joshua D
JD
Lawson
John
J
Einck
Cheryl
C
Saenz
Paul
P
Fanta
Arno J
AJ
Mundt
Graeme M
GM
Bydder
Loren K
LK
Mell
D000273:Adipose Tissue / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001005:Anus Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*; D001853:Bone Marrow / Q000000981:diagnostic imaging / Q000528:radiation effects*; D059248:Chemoradiotherapy / Q000379:methods; D002945:Cisplatin / Q000008:administration & dosage; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016685:Mitomycin / Q000008:administration & dosage; D064847:Multimodal Imaging; D059351:Organ Sparing Treatments / Q000379:methods*; D010388:Pelvis / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000097:blood / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D016685:Mitomycin; D002945:Cisplatin; D005472:Fluorouracil