Incidence of radiation pneumonitis after hepatic intra-arterial radiotherapy with yttrium-90 microspheres assuming uniform lung distribution.
OBJECTIVE
To assess the incidence of clinical and imaging radiation pneumonitis (RP) in a cohort of patients treated with >30 Gy cumulative lung dose (CLD) using Y90 microspheres.


METHODS
Four hundred three patients were treated with Y90 microspheres during a 4-year period. Of these, 58 patients received >30 Gy CLD. Patients were followed for toxicities suggestive of imaging or clinical RP. Toxicities were graded using the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer Late Radiation Morbidity Scoring Schema. Patients were also followed for survival from time of first treatment.


RESULTS
There were 44 men and 14 women. Forty-three patients had hepatocellular carcinoma (HCC), whereas 15 had liver metastases. Mean and median follow-up were 7.3 and 6.0 months, respectively. Mean lung shunt fraction was slightly greater in the patients with HCC versus metastases (20% vs. 16.7%, P = 0.2308). The lifetime CLD for metastases and HCC groups were not statistically different (54.04 Gy vs. 48.44 Gy, P = 0.4303). Forty-three of 53 patients demonstrated no lung imaging findings suggestive of pneumonitis. Imaging findings in 10 patients included pleural effusions, atelectasis, and ground glass attenuation. There were no cases of clinical or imaging RP. Survival varied depending on stage as well as single and CLD. None of the patient deaths were attributed to respiratory compromise.


CONCLUSIONS
RP was not predicted using the currently used Y90 dosimetry models that assume uniform distribution in the lungs. Further investigation and dose escalation studies are required to more precisely define the radiation tolerance of lung parenchyma using this mode of therapy.
Salem
Riad
R
Department of Radiology, Section of Interventional Radiology, Northwestern Memorial Hospital, Chicago, IL 60611, USA. r-salem@northwestern.edu
Parikh
Pankit
P
Atassi
Bassel
B
Lewandowski
Robert J
RJ
Ryu
Robert K
RK
Sato
Kent T
KT
Gates
Vanessa L
VL
Ibrahim
Saad
S
Mulcahy
Mary F
MF
Kulik
Laura
L
Liu
David M
DM
Riaz
Ahsun
A
Omary
Reed A
RA
Kennedy
Andrew S
AS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000532:radiotherapy*; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006499:Hepatic Artery / Q000528:radiation effects*; D006801:Humans; D015994:Incidence; D008113:Liver Neoplasms / Q000532:radiotherapy* / Q000556:secondary; D008168:Lung / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000209:etiology*; D019275:Radiopharmaceuticals / Q000009:adverse effects* / Q000493:pharmacokinetics; D011879:Radiotherapy Dosage; D015996:Survival Rate; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D015021:Yttrium Radioisotopes / Q000009:adverse effects* / Q000493:pharmacokinetics
D019275:Radiopharmaceuticals; D015021:Yttrium Radioisotopes