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Tumor T1 Relaxation Time for Assessing Response to Bevacizumab Anti-Angiogenic Therapy in a Mouse Ovarian Cancer Model.

Ravoori MK, Nishimura M, Singh SP, Lu C, Han L, Hobbs BP, Pradeep S, Choi HJ, Bankson JA, Sood AK, Kundra V - PLoS ONE (2015)

Bottom Line: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy.Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Systems Imaging, U.T.- M.D. Anderson Cancer Center, Houston, Texas, United States of America.

ABSTRACT

Purpose: To assess whether T1 relaxation time of tumors may be used to assess response to bevacizumab anti-angiogenic therapy.

Procedures: 12 female nude mice bearing subcutaneous SKOV3ip1-LC ovarian tumors were administered bevacizumab (6.25ug/g, n=6) or PBS (control, n=6) therapy twice a week for two weeks. T1 maps of tumors were generated before, two days, and 2 weeks after initiating therapy. Tumor weight was assessed by MR and at necropsy. Histology for microvessel density, proliferation, and apoptosis was performed.

Results: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy. Tumor T1 relaxation times increased in bevacizumab treated mice 2 days and 2 weeks after initiating therapy (p<.05, n=6). Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.

Conclusions: Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

No MeSH data available.


Related in: MedlinePlus

T1 values pre and post therapy.T1 values of tumors pre, 48 hour, and two weeks post therapy. *, p<.05. Error bars represent standard deviation.
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pone.0131095.g004: T1 values pre and post therapy.T1 values of tumors pre, 48 hour, and two weeks post therapy. *, p<.05. Error bars represent standard deviation.

Mentions: The T1 relaxation time was significantly increased in the bevacizumab treated group compared to controls, both two days (2302±567, mean ± standard deviation, vs 1729±209) and two weeks (2146±276 vs 1847±112) after initiation of therapy (p< 0.05, n = 6, Fig 4). There was variation in the T1 values (S1 Fig); therefore, to adjust for potential skewness in these comparisons, two-sided Wald tests using the robust estimation method described by Koller and Stahel [24] were applied. Significant differences in the extent of T1 relaxation time modification were evident between bevacizumab and control cohorts at each follow-up scan after adjusting for multiplicity. Statistically, robust inference estimates that the extent of relative change in T1 relaxation time was 16.1% (p≤0.011) larger on average for bevacizumab treated mice when compared to control mice after 48 hours. The result maintained statistical significance after 2 weeks, where T1 relaxation time was increased by 14.5% (p-value≤0.021) on average for bevacizumab treated mice. Prior to treatment, T1 relaxation time was 1877±60 for tumors from mice that subsequently were treated with bevacizumab. In comparison, the T1 value did not change from pre-therapy levels (1875±57) in the control group despite increase in tumor size.


Tumor T1 Relaxation Time for Assessing Response to Bevacizumab Anti-Angiogenic Therapy in a Mouse Ovarian Cancer Model.

Ravoori MK, Nishimura M, Singh SP, Lu C, Han L, Hobbs BP, Pradeep S, Choi HJ, Bankson JA, Sood AK, Kundra V - PLoS ONE (2015)

T1 values pre and post therapy.T1 values of tumors pre, 48 hour, and two weeks post therapy. *, p<.05. Error bars represent standard deviation.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4476738&req=5

pone.0131095.g004: T1 values pre and post therapy.T1 values of tumors pre, 48 hour, and two weeks post therapy. *, p<.05. Error bars represent standard deviation.
Mentions: The T1 relaxation time was significantly increased in the bevacizumab treated group compared to controls, both two days (2302±567, mean ± standard deviation, vs 1729±209) and two weeks (2146±276 vs 1847±112) after initiation of therapy (p< 0.05, n = 6, Fig 4). There was variation in the T1 values (S1 Fig); therefore, to adjust for potential skewness in these comparisons, two-sided Wald tests using the robust estimation method described by Koller and Stahel [24] were applied. Significant differences in the extent of T1 relaxation time modification were evident between bevacizumab and control cohorts at each follow-up scan after adjusting for multiplicity. Statistically, robust inference estimates that the extent of relative change in T1 relaxation time was 16.1% (p≤0.011) larger on average for bevacizumab treated mice when compared to control mice after 48 hours. The result maintained statistical significance after 2 weeks, where T1 relaxation time was increased by 14.5% (p-value≤0.021) on average for bevacizumab treated mice. Prior to treatment, T1 relaxation time was 1877±60 for tumors from mice that subsequently were treated with bevacizumab. In comparison, the T1 value did not change from pre-therapy levels (1875±57) in the control group despite increase in tumor size.

Bottom Line: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy.Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

View Article: PubMed Central - PubMed

Affiliation: Department of Cancer Systems Imaging, U.T.- M.D. Anderson Cancer Center, Houston, Texas, United States of America.

ABSTRACT

Purpose: To assess whether T1 relaxation time of tumors may be used to assess response to bevacizumab anti-angiogenic therapy.

Procedures: 12 female nude mice bearing subcutaneous SKOV3ip1-LC ovarian tumors were administered bevacizumab (6.25ug/g, n=6) or PBS (control, n=6) therapy twice a week for two weeks. T1 maps of tumors were generated before, two days, and 2 weeks after initiating therapy. Tumor weight was assessed by MR and at necropsy. Histology for microvessel density, proliferation, and apoptosis was performed.

Results: Bevacizumab treatment resulted in tumor growth inhibition (p<0.04, n=6), confirming therapeutic efficacy. Tumor T1 relaxation times increased in bevacizumab treated mice 2 days and 2 weeks after initiating therapy (p<.05, n=6). Microvessel density decreased 59% and cell proliferation (Ki67+) decreased 50% in the bevacizumab treatment group (p<.001, n=6), but not apoptosis.

Conclusions: Findings suggest that increased tumor T1 relaxation time is associated with response to bevacizumab therapy in ovarian cancer model and might serve as an early indicator of response.

No MeSH data available.


Related in: MedlinePlus