title: Impact of splenomegaly on therapeutic response and I-131-LYM-1 dosimetry in patients with B-lymphocytic malignancies.
abstract: BACKGROUND
  Patients with B-cell non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) frequently have splenomegaly, which has been reported to cause poor tumor targeting of radiolabeled antibodies. Consequently, patients with splenomegaly have been ineligible for some trials of radioimmunotherapy because of the assumption that they would not benefit.
  
  
  METHODS
  Forty-nine patients with NHL and five with CLL received an initial dose of 131I-Lym-1 ranging from 740-8140 MBq. Six patients had prior splenectomy. The remaining 48 patients had spleen volumes ranging from 140-2830 ml determined using x-ray computed tomography. Medical Internal Radiation Dose Committee formalism was used to determine dosimetry, and spleen volume was used to adjust the S value for the spleen of each patient.
  
  
  RESULTS
  Spleen radiation dose decreased as spleen volume increased, although there was a positive correlation (r = 0.75) between spleen volume and spleen cumulated activity. There was no clear relationship between spleen volume and tumor radiation dose, although tumor radiation doses were low in five patients whose spleen volumes were greater than or equal to 970 ml. There was no apparent relationship between spleen volume and therapeutic response to 131I-Lym-1. Two of five patients whose spleen volumes were greater than or equal to 970 ml responded despite low tumor radiation doses, whereas two of six patients with prior splenectomy did not respond.
  
  
  CONCLUSIONS
  The results of this study provide no clear evidence that patients with splenomegaly should be excluded from radioimmunotherapy trials because of the assumption that they will not benefit. Splenomegaly was associated with decreased radiation dose to the spleen, and to tumors only for extraordinarily large spleens.
authors.affiliation: University of California at Davis, School of Medicine, Sacramento, USA.
authors.forename: S
authors.initials: S
authors.lastname: Shen
authors.forename: G L
authors.initials: GL
authors.lastname: DeNardo
authors.forename: R T
authors.initials: RT
authors.lastname: O'Donnell
authors.forename: A
authors.initials: A
authors.lastname: Yuan
authors.forename: D A
authors.initials: DA
authors.lastname: DeNardo
authors.forename: S J
authors.initials: SJ
authors.lastname: DeNardo
mesh_terms: D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000532:radiotherapy*; D008228:Lymphoma, Non-Hodgkin / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D011879:Radiotherapy Dosage; D013163:Splenomegaly / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes