Prognostic value of (99m)Tc-sestamibi washout in predicting response of locally advanced breast cancer to neoadjuvant chemotherapy.
This study evaluated the role of (99m)Tc-sestamibi washout in the prediction of pathologic tumor response to neoadjuvant chemotherapy in 30 patients with locally advanced breast cancer.


METHODS
Two (99m)Tc-sestamibi studies were performed before and after chemotherapy for each patient. Early (10 min) and delayed (240 min) planar breast views were acquired after a 740-MBq (99m)Tc-sestamibi intravenous injection, and the washout rate (WOR) was computed. All patients underwent radical mastectomy with pathologic evaluation of the residual tumor size.


RESULTS
The pretherapy (99m)Tc-sestamibi WOR ranged from 14% to 92% (mean +/- SD, 50% +/- 18%). At pathologic examination, 15 patients showed no tumor response to chemotherapy and 15 patients showed an objective response to chemotherapy. The pretherapy (99m)Tc-sestamibi study predicted chemoresistance (WOR > 45%) in 18 of 30 patients and no chemoresistance (WOR < or = 45%) in 12 of 30 patients. When the WOR cutoff was set at >45%, the prognostic performance of the test was indicated by a sensitivity of 100%; a specificity of 80%; positive and negative predictive values of 83% and 100%, respectively; and a likelihood ratio of 5. The repeatability of the test was good, with 80%-93% interreader agreement (kappa = 0.57-0.85). Posttherapy (99m)Tc-sestamibi studies confirmed the pretherapy study prediction in 29 of 30 patients.


CONCLUSIONS
(99m)Tc-Sestamibi WOR is a reliable test for predicting tumor response to neoadjuvant chemotherapy. In fact, negative findings (WOR < or = 45%) rule out chemoresistance and positive findings (WOR > 45%) indicate a high risk of chemoresistance.
Sciuto
Rosa
R
Department of Nuclear Medicine, Regina Elena Cancer Institute, Rome, Italy. sciuto@ifo.it
Pasqualoni
Rosella
R
Bergomi
Serenella
S
Petrilli
Germana
G
Vici
Patrizia
P
Belli
Franca
F
Botti
Claudio
C
Mottolese
Marcella
M
Maini
Carlo L
CL
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000601:surgery; D018432:Drug Resistance, Multiple; D005260:Female; D006801:Humans; D015409:Mastectomy, Radical; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013997:Time Factors; D016896:Treatment Outcome
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi