Optimized conformal paraaortic lymph node irradiation is not associated with enhanced renal toxicity.
OBJECTIVE
For patients with gynecologic carcinomas, irradiation of paraaortic lymph nodes (PLNs) is a routine treatment concept. Planning target volumes (PTVs) individually optimized by radiation field delineations along the big vessels permit the inclusion of at least 97% of potentially involved PLNs. However, this novel treatment technique might increase radiation-induced nephrotoxicity. Therefore, the actual incidence of kidney damage after PLN irradiation has to be assessed in order to validate the safety of this treatment concept.


METHODS
19 patients were treated with irradiation alone (50.4 Gy; 5 x 1.8 Gy/week) and monitored for up to 90 months. Functional renal parameters, namely renal plasma flow (RPF) and glomerular filtration rate (GFR), were assessed by dynamic renal scintigraphy. Additionally, patients were clinically observed (i.e., hypertension, proteinuria) and calculations of normal-tissue complication probability (NTCP) values for nonuniform kidney irradiation were performed using the Lyman-Wolbarst algorithm.


RESULTS
Two patients with anticipated moderate NTCP values (12.6% and 8.7%) showed slightly impaired RPF rates at 12, 24, and after 48 months of follow-up. Only one patient in the subgroup showing NTCP values > 50% (n = 9) developed a notable impairment of renal RPF. However, all patients including those with elevated complication probabilities exhibited neither impaired GFR nor clinically apparent symptoms related to a loss of functioning renal tissue from 12 to > 48 months post irradiation.


CONCLUSIONS
Conformal irradiation of retroperitoneal lymph nodes with individual PTV delineation appears not to be associated with clinically relevant functional impairment of the kidneys.
Nevinny-Stickel
Meinhard
M
Department of Therapeutic Radiology and Oncology, Innsbruck Medical University, Austria. meinhard.nevinny@uibk.ac.at
Poljanc
Karin
K
Forthuber
Britta C
BC
Heute
Dirk
D
Posch
Andrea
A
Lechner
Judith
J
Beer
Beate
B
Lukas
Peter
P
Seppi
Thomas
T
D000328:Adult; D000368:Aged; D001011:Aorta / Q000528:radiation effects; D002277:Carcinoma / Q000532:radiotherapy* / Q000556:secondary*; D005260:Female; D005833:Genital Neoplasms, Female / Q000532:radiotherapy*; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis* / Q000209:etiology*; D008198:Lymph Nodes / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology*; D020266:Radiotherapy, Conformal / Q000379:methods*; D016896:Treatment Outcome