Gamma camera scans and pretreatment tumor volumes as predictors of response and progression after Y-90 anti-CD20 radioimmunotherapy

Abhay S. Gokhale, Jyoti Mayadev, Brad Pohlman, Roger M. Macklis

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Purpose: To evaluate two potential approaches to predicting site-specific patterns of recurrence after yttrium-90 ibritumomab tiuxetan radioimmunotherapy (RIT) for CD20+ B-cell Non-Hodgkin's lymphoma. These predictive methods may be useful in evaluating the utility of local intensification of individual nodal or extranodal sites using external beam radiotherapy. Methods and Materials: Records and images were evaluated for 20 patients previously treated with yttrium-90 ibritumomab RIT. Intensity of isotope uptake on the pretreatment two-dimensional antibody scans and maximal extent of tumor deposits found on computed tomography images of each anatomic site were correlated with response and subsequent patterns of recurrence or progression. Results: Our data failed to suggest a significant correlation between the site-by-site two-dimensional image intensity on the pre-RIT scan and the likelihood of response at those sites. In contrast, an analysis of pretreatment target volumes did correlate significantly with progression. A collective analysis of disease sites from all 20 patients found that 83% (10/12) sites of "bulky" (maximal diameter SS cm) disease displayed evidence of progression vs. 28% (26/93) of "nonbulky" disease sites containing gross disease but no area measuring >5 cm (p < 0.001). All patients with at least one site of bulky disease had initial disease progression occur at a bulky site, with a bulky site being the sole first site of progression in approximately 50%. In patients with only nonbulky disease sites, approximately one third progressed initially at an entirely new site of disease. Conclusion: We conclude that we can use tumor bulk to establish a statistical hierarchy of likely tumor progression sites and use this pattern to direct the use of additional external beam radiotherapy to augment treatment.

Original languageEnglish (US)
Pages (from-to)194-201
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number1
StatePublished - Sep 1 2005
Externally publishedYes


  • Ibritumomab tiuxetan
  • Non-Hodgkin's lymphoma
  • Radioimmunotherapy

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation


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