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Radiobiological Modeling Based on (18)F-Fluorodeoxyglucose Positron Emission Tomography Data for Esophageal Cancer.

Guerrero M, Tan S, Lu W - J Nucl Med Radiat Ther (2014)

Bottom Line: High initial SUV and larger metabolic response (larger <SUVbefore -SUVafter>) were correlated, and this correlation was stronger among responders.Our TCP model indicates that <SUVafter/SUVbefore> is a possible surrogate for cell survival in esophageal cancer patients.Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, 21201, USA.

ABSTRACT

Background: We investigated the relationship of standardized uptake values (SUVs) to radiobiological parameters, such a 25 s tumor control probability (TCP), to allow for quantitative prediction of tumor response based on SUVs from (18)F fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) before and after treatment for esophageal cancer.

Methods: We analyzed data from 20 esophageal cancer patients treated with chemoradiotherapy (CRT) followed by surgery. Tumor pathologic response to CRT was assessed in surgical specimens. Patients underwent (18)F-FDG PET imaging before and after CRT. Rigid image registration was performed between both images. Because TCP in a heterogeneous tumor is a function of average cell survival, we modeled TCP as a function of , a possible surrogate for average cell survival (=). TCP was represented by a sigmoid function with two parameters: SUVR50, the at which TCP=0.5, and γ50, the slope of the curve at SUVR50. The two parameters and their confidence intervals (CIs) were estimated using the maximum-likelihood method. The correlation between SUV before CRT and SUV change was also studied.

Results: A TCP model as a function of SUV before and after treatment was developed for esophageal cancer patients. The maximum-likelihood estimate of SUVR50 was 0.47 (90% CI, 0.30-0.61) and for γ50 was 1.62 (90% CI, 0-4.2). High initial SUV and larger metabolic response (larger ) were correlated, and this correlation was stronger among responders.

Conclusions: Our TCP model indicates that is a possible surrogate for cell survival in esophageal cancer patients. Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients. Initial SUV does not predict response, whereas a correlation is found between surrogates for initial tumor burden and cell kill during therapy.

No MeSH data available.


Related in: MedlinePlus

Scatter plot of the difference <SUVbefore> − <SUVafter> as a function of <SUVbefore>. A significant correlation is seen among those quantities.
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Figure 4: Scatter plot of the difference <SUVbefore> − <SUVafter> as a function of <SUVbefore>. A significant correlation is seen among those quantities.

Mentions: Table 1 also shows that <SUVbefore> tends to be higher for responders than for non responders. This trend, although not significant, seems to contradict the assumption that SUV is correlated with tumor burden, because we expect nonresponders to have higher tumor burdens than responders. This trend has been observed before in studies of initial SUVmax for lung cancer [17] as well as in esophageal cancer [18]. To address this puzzling issue, we studied the correlation of <SUVbefore> with <SUVafter/SUVbefore> and <SUVbefore−SUVafter> to determine whether the response surrogates are correlated with the initial SUV values. Figure 4 shows a significant correlation between <SUVbefore> −<SUVafter> and <SUVbefore> (Pearson correlation coefficient=0.77; P=0.0008).


Radiobiological Modeling Based on (18)F-Fluorodeoxyglucose Positron Emission Tomography Data for Esophageal Cancer.

Guerrero M, Tan S, Lu W - J Nucl Med Radiat Ther (2014)

Scatter plot of the difference <SUVbefore> − <SUVafter> as a function of <SUVbefore>. A significant correlation is seen among those quantities.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4286330&req=5

Figure 4: Scatter plot of the difference <SUVbefore> − <SUVafter> as a function of <SUVbefore>. A significant correlation is seen among those quantities.
Mentions: Table 1 also shows that <SUVbefore> tends to be higher for responders than for non responders. This trend, although not significant, seems to contradict the assumption that SUV is correlated with tumor burden, because we expect nonresponders to have higher tumor burdens than responders. This trend has been observed before in studies of initial SUVmax for lung cancer [17] as well as in esophageal cancer [18]. To address this puzzling issue, we studied the correlation of <SUVbefore> with <SUVafter/SUVbefore> and <SUVbefore−SUVafter> to determine whether the response surrogates are correlated with the initial SUV values. Figure 4 shows a significant correlation between <SUVbefore> −<SUVafter> and <SUVbefore> (Pearson correlation coefficient=0.77; P=0.0008).

Bottom Line: High initial SUV and larger metabolic response (larger <SUVbefore -SUVafter>) were correlated, and this correlation was stronger among responders.Our TCP model indicates that <SUVafter/SUVbefore> is a possible surrogate for cell survival in esophageal cancer patients.Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, 21201, USA.

ABSTRACT

Background: We investigated the relationship of standardized uptake values (SUVs) to radiobiological parameters, such a 25 s tumor control probability (TCP), to allow for quantitative prediction of tumor response based on SUVs from (18)F fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) before and after treatment for esophageal cancer.

Methods: We analyzed data from 20 esophageal cancer patients treated with chemoradiotherapy (CRT) followed by surgery. Tumor pathologic response to CRT was assessed in surgical specimens. Patients underwent (18)F-FDG PET imaging before and after CRT. Rigid image registration was performed between both images. Because TCP in a heterogeneous tumor is a function of average cell survival, we modeled TCP as a function of , a possible surrogate for average cell survival (=). TCP was represented by a sigmoid function with two parameters: SUVR50, the at which TCP=0.5, and γ50, the slope of the curve at SUVR50. The two parameters and their confidence intervals (CIs) were estimated using the maximum-likelihood method. The correlation between SUV before CRT and SUV change was also studied.

Results: A TCP model as a function of SUV before and after treatment was developed for esophageal cancer patients. The maximum-likelihood estimate of SUVR50 was 0.47 (90% CI, 0.30-0.61) and for γ50 was 1.62 (90% CI, 0-4.2). High initial SUV and larger metabolic response (larger ) were correlated, and this correlation was stronger among responders.

Conclusions: Our TCP model indicates that is a possible surrogate for cell survival in esophageal cancer patients. Although CIs are large as a result of the small patient sample, parameters for a TCP curve can be derived and an individualized TCP can be calculated for future patients. Initial SUV does not predict response, whereas a correlation is found between surrogates for initial tumor burden and cell kill during therapy.

No MeSH data available.


Related in: MedlinePlus