PET and PET-CT Imaging in Treatment Monitoring of Breast Cancer Rakesh Kumar, MD a, *, Madhavi Chawla, MD a , Sandip Basu, MBBS (Hons), DRM, DNB, MNAMS b , Abass Alavi, MD, MD (Hon), PhD (Hon), DSc (Hon) c Breast cancer is the most frequently diagnosed cancer in women. It remains the second most frequent cause of cancer death after lung and bronchial cancers in women worldwide. Breast cancer is one of the more responsive solid tumors, 1 for which a wide range of systemic therapy options are available. Therefore, appro- priate evaluation of early response to therapy is an important diagnostic need for breast cancer. The treatment of newly diagnosed breast cancer is primarily determined by the extent of disease and generally includes surgery, radiation, and chemotherapy. Primary systemic chemotherapy or neoadjuvant chemotherapy, introduced for managing inoperable and large or locally advanced breast tumors, 2 is now increasingly being used to downstage tumor load before surgery. This renders previously inoperable breast cancer resectable, permitting breast-conserving surgery and sentinel node biopsy instead of subsequent axillary lymph node dissection. 3–5 The therapeutic options available for patients with metastatic breast cancer are various, 6,7 de- pending on the histopathology and the extent of disease. Patients with estrogen receptor–positive tumors and a small volume of metastatic disease are treated with endocrine agents, 7 patients with HER2-positive tumors are treated with a combina- tion of trastuzumab and chemotherapy, 8 and the only current treatment option available for patients with triple-negative tumors (ie, estrogen-negative, progesterone-negative, and HER2-negative tumors) is chemotherapy. 9 IMAGING MODALITIES EVALUATING TREATMENT RESPONSE IN BREAST CANCER Various imaging modalities are available for staging, restaging and response evaluation in oncology. Standard imaging techniques for breast carcinoma include radiologic examinations, such as x-ray mammography, Doppler ultrasonog- raphy, 10 computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy, 11,12 and optical imaging. 13 Among these functional imaging modalities, contrast- enhanced MRI is the most widely used in clinical practice, as it provides a detailed anatomic picture of the extent of disease, which is important for surgical planning after therapy. 14 Combining MRI and contrast-enhanced MRI has a diagnostic accuracy of 93% for identifying tumors showing a pathologic complete response (pCR). 15 Nuclear medicine techniques also play an important role in diagnosing and staging breast cancer. In the past, only bone scintigraphy was used to detect bone metastases at an early stage. 16 This tech- nique was followed by imaging using monoclonal a Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi 110029, India b Radiation Medicine Centre, Bhabha Atomic Research Centre, Mumbai, India c Nuclear Medicine Section, Radiology Department, Hospital of the University of Pennsylvania, Philadelphia, PA, USA * Corresponding author. E-mail address: [email protected] (R. Kumar). KEYWORDS Breast cancer 18 F-FDG PET Tumor Chemotherapy PET Clin 4 (2009) 359–369 doi:10.1016/j.cpet.2009.09.008 1556-8598/09/$ – see front matter ª 2009 Elsevier Inc. All rights reserved. pet.theclinics.com
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PET and PET-CTImaging in TreatmentMonitoring ofBreast Cancer
� Breast cancer � 18F-FDG PET � Tumor � Chemotherapy
Breast cancer is the most frequently diagnosedcancer in women. It remains the second mostfrequent cause of cancer death after lung andbronchial cancers in women worldwide. Breastcancer is one of the more responsive solidtumors,1 for which a wide range of systemictherapy options are available. Therefore, appro-priate evaluation of early response to therapy isan important diagnostic need for breast cancer.The treatment of newly diagnosed breast canceris primarily determined by the extent of diseaseand generally includes surgery, radiation, andchemotherapy. Primary systemic chemotherapyor neoadjuvant chemotherapy, introduced formanaging inoperable and large or locallyadvanced breast tumors,2 is now increasinglybeing used to downstage tumor load beforesurgery. This renders previously inoperable breastcancer resectable, permitting breast-conservingsurgery and sentinel node biopsy instead ofsubsequent axillary lymph node dissection.3–5
The therapeutic options available for patientswith metastatic breast cancer are various,6,7 de-pending on the histopathology and the extent ofdisease. Patients with estrogen receptor–positivetumors and a small volume of metastatic diseaseare treated with endocrine agents,7 patients withHER2-positive tumors are treated with a combina-tion of trastuzumab and chemotherapy,8 and the
a Department of Nuclear Medicine, All India Institute ofb Radiation Medicine Centre, Bhabha Atomic Research Cc Nuclear Medicine Section, Radiology Department, HosPA, USA* Corresponding author.E-mail address: [email protected] (R. Kumar).
PET Clin 4 (2009) 359–369doi:10.1016/j.cpet.2009.09.0081556-8598/09/$ – see front matter ª 2009 Elsevier Inc. All
only current treatment option available for patientswith triple-negative tumors (ie, estrogen-negative,progesterone-negative, and HER2-negativetumors) is chemotherapy.9
IMAGING MODALITIES EVALUATINGTREATMENT RESPONSE IN BREAST CANCER
Various imaging modalities are available forstaging, restaging and response evaluation inoncology. Standard imaging techniques for breastcarcinoma include radiologic examinations, suchas x-ray mammography, Doppler ultrasonog-raphy,10 computed tomography (CT), magneticresonance imaging (MRI), magnetic resonancespectroscopy,11,12 and optical imaging.13 Amongthese functional imaging modalities, contrast-enhanced MRI is the most widely used in clinicalpractice, as it provides a detailed anatomic pictureof the extent of disease, which is important forsurgical planning after therapy.14 Combining MRIand contrast-enhanced MRI has a diagnosticaccuracy of 93% for identifying tumors showinga pathologic complete response (pCR).15 Nuclearmedicine techniques also play an important rolein diagnosing and staging breast cancer. In thepast, only bone scintigraphy was used to detectbone metastases at an early stage.16 This tech-nique was followed by imaging using monoclonal
Medical Sciences, New Delhi 110029, Indiaentre, Mumbai, India
pital of the University of Pennsylvania, Philadelphia,
antibodies against carcinoembryonic antigens andother antigens expressed in breast cancer andimaging with 99mTc-tetrofosmin or 99mTc-sestami-bi for primary and recurrent disease.17,18 Since theintroduction of positron emission tomography(PET) in clinical oncology, 18F-fluorodeoxyglucose(18F-FDG) PET has been shown to be an effectiveand accurate imaging modality for staging and re-staging of recurrent and metastatic disease andfor treatment monitoring.19–22
Treatment Response Evaluation of PrimaryBreast Cancer
Sequential 18F-FDG PET imaging has been widelystudied as a method for assessing tumor responseto neoadjuvant chemotherapy. The concept ofusing 18F-FDG PET for predicting a therapeuticresponse is based on early changes in tumorglucose use and the close correlation of changesin 18F-FDG uptake with the effectiveness oftherapy.23,24 In all these studies, 18F-FDG PETscans were obtained before therapy and then atvariable intervals during the course of neoadjuvanttherapy (Fig. 1). Comparison of the levels of radio-tracer uptake in the baseline scan and in subse-quent posttherapy scans helped in earlyidentification of responders and in differentiatingthem from the nonresponders. Currently there is
Fig. 1. Coronal, sagittal, and axial sections of PET-CT showright breast in baseline PET-CT study (top). Follow-up studresolution of right breast tumor (bottom).
no definite consensus about the optimal timing ofFDG PET, and studies have been performed atvarious points after chemotherapy. In most ofthese studies, a single scan was performed earlyduring the course of treatment.25–34 Other studiesincluded 2 or 3 scans performed sequentiallyduring the course of treatment.23,35–42 Studies ofFDG PET after the first cycle of chemotherapyhave shown sensitivities ranging from 39% to100%.23,37,38,40 Specificities ranged from 74%to100%.23,37,38,40 Corresponding range of sensi-tivities and specificities after the second cyclewere 69% to93%32,38,40 and 75% to94%,32,38,40
respectively. Literature suggests that responseevaluation is most effective after the second cycle(Fig. 2).40 Evaluation of treatment response afterthe first cycle of chemotherapy will have loweraccuracy, and evaluation after 3 or more cycleswill be too late to make an effective alterationand the patient will already have been exposedto ineffective and toxic chemotherapy (Table 1).
ANALYSIS AND ASSESSMENT OF TUMORRESPONSE TO THERAPY
Several methods for quantitative analysis of FDGdata have been proposed.44 In the dynamic scan-ning protocol, an attempt to measure glucose
ing a focal area of intense increased FDG uptake iny, after completion of chemotherapy, shows complete
Fig. 2. Coronal, sagittal, and projection image of PET-CT showing a focal area of intense increased FDG uptakewith central necrosis in left breast and multiple left axillary lymph nodes in baseline PET-CT study (top).Follow-up study, after completion of chemotherapy, shows complete resolution of right breast tumor and axillarylymph nodes (bottom).
PET-CT in Therapy 361
metabolic rate is made. This protocol is, however,considered to be too time-consuming and techni-cally demanding for routine clinical use, which hasresulted in the development of methods thatrequire just a single static scan. At present, thestandard uptake value (SUV) method is mostwidely used. This method requires a single scanto measure the uptake of FDG, which is thennormalized to injected dose and body weight.Normalization to body surface area or lean bodymass can also be done.45–48 Definition of thetumor region of interest for the calculation ofSUV is of crucial importance in monitoring tumoruptake of FDG during therapy. Reproducibility,user independence, and, to a lesser degree,simplicity are important considerations whenchoosing a region-of-interest method.
In most studies, histopathologic assessment ofresponse to therapy from the postsurgicalspecimen was used as the gold stan-dard,23,25,26,32,36–38,40–43 pCR being defined bythe absence of residual invasive tumor.49–51
However, no difference was found in survival ratesbetween patients with scattered microscopic fociof residual tumor cells and patients who achieveda pCR.52 Thus both groups were classified togetheras minimal residual disease, all other responsesbeing classified as gross residual disease. Otherstudies used clinical evaluation,28,35 assessmentof size by conventional imaging methods,34,35
tumor marker levels,27 recurrence rate, andmortality rate31 as reference parameters.
Two important criteria, namely, the World HealthOrganization criteria53 and RECIST (responseevaluation criteria in solid tumors) criteria,54 basedon conventional imaging modalities, have beendescribed in the literature to define the tumorresponse. Assessment of tumor size using RECISTcriteria was the commonest among these. TheRECIST criteria define a response as a decreasein the maximum tumor diameter of at least30%.54 Despite the wide acceptance of theabove-mentioned criteria in clinical practice, therewere a few limitations in evaluation of treatment
T le 1S dies evaluating treatment response using PET/PET-CT in patients with breast cancer
A thors YearNumber ofPatients Stage Isotope
Serial PET(Number of Cycles)
ReferenceStandard Sensitivity Specificity
W hl et al23 1993 11 IIIB/LABC FDG First (11)Second (11)Third (11)
HPR 100 100
B ce et al25 1995 12 LABC FDG Second (5) HPR — —
J sson et al35 1995 16 LABC/IV FDG/11C MET
First (7)Third/fourth (7)
Clinical/conventional
Imaging
— —
B ssa et al36 1996 16 LABC FDG Mid (13)Presurgery (14)
HPR 75 —
S ith et al37 2000 30 T3/LABC FDG First (28)Fourth (19)Eighth (21)
HPR 90 74
S elling et al38 2000 22 LABC FDG First (14)Second (20)
HPR 10083
8594
T ng et al39 2001 7 LABC FDG Day 8 (7)Second (7)
— —
M nkoff et al26 2003 35 LABC FDG/15O-H2O
Mid (21) Tumor sizeHPR
— —
K et al43 2004 50 LABC Complete (50) HPR 85 83
R usseau et al40 2006 64 II/III FDG First (64)Second (64)Third (64)
HPR 396979
968977
P et al27 2006 14 Primary/metastatic
FLT First (14) CA27.29 CT — —
K nny et al28 2007 13 II–IV FLT First (13) Clinical response — —
M Dermott et al41 2007 NA LABC FDG FirstMid
HPR 100 77
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PET-CT in Therapy 363
response. An important limitation is the assump-tion that the chemotherapy agent under review iscytocidal and that it will lead to cell death followedby reduction in tumor size. The cut off criteria of50% or 30% reduction in tumor size are arbitrarypercentages and are not based on outcomestudies. Several cycles of treatment are neededbefore a change in tumor size can be assessedby anatomic imaging. This approach works wellfor some sites of metastatic disease, such as theliver and lungs, but regional nodal disease andbones are difficult to evaluate.55 These limitationsof CT/MRI can be effectively overcome by func-tional imaging techniques, which have the uniqueability to detect subclinical alterations in tumorphysiology and biochemistry resulting from effica-cious therapy.56 Besides this, 18F-FDG PET alsoidentified patients with low tumor metabolicactivity before treatment as not achieving histo-pathologic response, suggesting that breastcancers with low metabolic activity are not likelyto respond to primary chemotherapy, thus guidinginitial management.40–42,57
The presence of residual tumor in axillary lymphnodes after chemotherapy is an independentrisk factor for locoregional recurrence in locallyadvanced breast cancer (LABC).58,59 However,response monitoring data on the axillary statusare scarce. Only 3 studies have looked specifi-cally at response of axillary lymph nodes. Smithand colleagues37 found a significantly greatermean decrease in FDG uptake after 1 cycle oftherapy in lymph nodes with pathologic micro-scopic residual disease than in nonrespondingnodes. Bassa and colleagues36 and Buscombeand colleagues60 reported sensitivities for de-tecting residual lymph node involvement aftercompletion of therapy of 42% and 40%, respec-tively. Specificity was 100% in both studies.Studies performed after the completion ofchemotherapy have shown that althoughresidual 18F-FDG uptake predicts residualdisease, the absence of 18F-FDG uptake is nota reliable indicator of pCR.36,60–62 This is espe-cially true for axillary nodal disease, becausethe sensitivity for residual microscopic diseaseafter therapy is low. There is a relative paucityof studies that had evaluated the role of meta-static disease other than bone and axillarylymph nodes (Fig. 3).
The bone is the most common site of distantmetastasis, and metastases to the bone arediagnosed in 30% to 85% of patients with
Fig. 3. Coronal and axial section of PET-CT showing a focal area of intense increased FDG uptake in liver sugges-tive of metastasis in a patient with breast cancer (A). Follow-up study, after 6 cycles of chemotherapy, showsresolution of liver lesion (B).
Kumar et al364
advanced breast cancer.63 Bone metastasiscauses much of the morbidity and disability inpatients with breast cancer because of itspotentially prolonged clinical course. Relativelysmall studies have been conducted evaluatingserial 18F-FDG PET for measuring metastaticbreast cancer response to treatment. Moststudies concluded that response is accompa-nied by substantial drops in 18F-FDG uptake,typically 40% to 50% or more from the prether-apy baseline scans.64–66 Most studies evaluatedresponse after the first cycle of chemo-therapy.27,28,33,66 Additional scans were per-formed after the second,65 third,64 or third/fourth35 cycle in some studies. Clinicalresponse,28,35,64 conventional imaging,27,35,65
tumor markers,27 circulating tumor cell counts,and survival rates67 were used as the referencestandards in patients with bone metastasis.Some studies suggested that imaging as early
as after 1 cycle of chemotherapy could predictresponse,66 akin to the neoadjuvant therapysetting. However, other studies have not shownsimilar accuracy for early repeated 18F-FDGPET.64 Even though favorable results havebeen reported, prospective, multicenter clinicaltrials are needed to validate the efficacy for18F-FDG PET/CT for evaluating bone metastasisresponse and to enable their more widespreadclinical use in bone-dominant breast cancer(Table 2).
FLARE PHENOMENON IN THE SCENARIOOF THERAPEUTIC RESPONSEIN BREAST CARCINOMA
Although FDG PET has been a highly successfulmodality in monitoring response to treatment,tumor recurrence, and restaging, one must keepin mind the phenomenon of ‘‘metabolic flare,’’
Table 2Studies evaluating treatment response using PET/PET-CT in patients with metastatic breast cancer
Authors YearNumber ofPatients Isotope
Serial PET(Number of Cycles)
ReferenceStandard
Jansson et al35 1995 4 FDG/11C-MET
FirstThird/fourth
Clinical/conventionalimaging
Gennari et al66 2000 9 FDG First
Dose Schwarz et al65 2005 11 FDG FirstSecond
Conventionalimaging
Pio et al27 2006 14 FLT First (14) CA27.29 CT
Couturier et al64 2006 20 FDG FirstThird
Clinical response
Specht et al78 2007 28 FDG Mid
Kenny et al28 2007 13 FLT First (13) Clinical response
Lindholm et al33 2009 13 11C-MET First
DeGiorgi et al67 2009 115 FDG Mid Circulating tumorcell count
which is a transient increase in FDG activity veryearly in the course of therapy. Such an increaseoccurs 7 to 10 days after initiating hormonaltherapy because of partial estrogen-like agonisteffects of tamoxifen and should not be construedas disease progression. Metabolic flare alsooccurs after radiation/systemic therapy becauseof the accumulation of inflammatory cells at thetreatment site.
TREATMENT RESPONSE EVALUATIONWITH OTHER TRACERS
Studies of 18F-FDG PET have shown that tumorglycolysis declines early in the course of treat-ment,37,38 providing a means for early responseassessment. However, other pathways moreclosely related to perfusion, cellular growth, anddeath may provide even earlier and more specificindications of therapeutic response. Tumor perfu-sion may influence response to systemic chemo-therapy68 and good perfusion is crucial for thedelivery of chemotherapy to the tumor cell,69 whichis evaluated using 15O-water PET.70 Tumors withlow perfusion may be hypoxic, and hypoxia hasbeen related to aggressive tumor behavior andpoor response to chemotherapy.71 Mankoff andcolleagues26 and Dunnwald and colleagues31 used15O-water for midcycle assessment of response totherapy in patients with LABC and have shownthat serial measures of breast cancer perfusion by15O-water PET in the neoadjuvant setting are highlypredictive of response and survival. Some studieshave suggested that dynamic 18F-FDG PET and
kinetic analysis may yield estimates of tumor perfu-sion, inferred from the 18F-FDG delivery kineticparameter, comparable to 15O-water PET.72–74
This approach, therefore, merits further investiga-tion. Table 3 lists the studies done with PET radio-pharmaceuticals other than FDG.
The uptake of labeled amino acids, such as 11C-methionine (MET), correlates with tumor growth,and changes in uptake provide an early indicationof breast cancer response to therapy. Janssonand colleagues35 performed 11C-MET PET in 11patients with LABC/stage IV, either alone or inconjunction with FDG PET, after the first and thethird/fourth course of chemotherapy. Clinical eval-uation and conventional imaging were used as thereference standards. A similar study after the firstcycle was performed by Lindholm andcolleagues33 in 13 patients with metastatic breastcarcinoma. Both the studies showed changes inuptake, providing an early indication of breastcancer response to therapy.35
Aberrant cellular proliferation can be studiedusing 18F-fluorothymidine (18F-FLT). Responseevaluation after a single cycle of chemotherapyin patients with primary/metastatic disease hasbeen studied by Pio and colleagues27 and Kennyand colleagues28 in 14 and 13 patients, respec-tively, and appears especially promising formeasuring the early effects of therapy on breastcancer growth.
16a-18F-fluoro-17b-estradiol (18F-FES)75 PETappears to be a promising tracer for noninvasivelydetermining the estrogen receptor status of meta-static breast cancer and predicting the response
Table 3Studies evaluating treatment response using isotopes other than FDG in patients withprimary/metastatic breast cancer
Authors Year
NumberofPatients Stage Isotope
Serial PET(Number ofCycles)
ReferenceStandard
Jansson et al35 1995 16 LABC/IV FDG/11C-MET
First (7)Third (7)
Conventionalimaging
Mankoff et al26 2003 35 LABC FDG/15O-H2O
Mid (21) Tumor sizeHPR
Pio et al27 2006 14 Primary/metastatic
FLT First (14) CA27.29CT
Kenny et al28 2007 13 II-IV FLT First (13) Clinicalresponse
to endocrine therapy. Similarly, HER2 (ErbB2)expression in breast cancer is an important indi-cator of prognosis and an increasingly importanttarget for therapy.76 Studies using a 68Ga-labeledF(ab9)2 fragment of trastuzumab77 demonstratedthe feasibility of measuring regional HER2 expres-sion in murine animal models. However, furtherstudies are merited before these radiotracers areput into clinical use.
SUMMARY
Breast cancer is a more responsive solid tumorwith a wide range of systemic therapy options.The early identification of nonresponders is impor-tant because the availability of newer chemo-therapy agents helps in avoiding expensive,ineffective, and toxic drugs and because of thepossibility to switch over to alternative treatmentmethods. 18F-FDG, being a glucose analog, canpredict therapeutic response based on earlychanges in tumor glucose use, which correlateswell with the effectiveness of treatment. 18F-FDGPET thus serves as an effective and accurateimaging modality for staging and restaging ofrecurrent and metastatic disease, and early treat-ment monitoring.
ACKNOWLEDGMENTS
This work also was supported in part by theCouncil of Scientific and Industrial Research,New Delhi, India under Senior Research AssociateFellowship.
REFERENCES
1. Gralow JR. Optimizing the treatment of metastatic
breast cancer. Breast Cancer Res Treat 2005;
89(Suppl 1):S9–15.
2. Bonadonna G, Valagussa P, Zucali R, et al. Primary
chemotherapy in surgically resectable breast
cancer. CA Cancer J Clin 1995;45:227–43.
3. Moneer M, Ismael S, Khaled H, et al. A new surgical
strategy for breast conservation in locally advanced
breast cancer that achieves a good locoregional
control rate: preliminary report. Breast 2001;10:
220–4.
4. Stearns V, Ewing CA, Slack R, et al. Sentinel lympha-
denectomy after neoadjuvant chemotherapy for
breast cancer may reliably represent the axilla
except for inflammatory breast cancer. Ann Surg
Oncol 2002;9:235–42.
5. Breslin TM, Cohen L, Sahin A, et al. Sentinel lymph
node biopsy is accurate after neoadjuvant chemo-
therapy for breast cancer. J Clin Oncol 2000;18:
3480–6.
6. Hamilton A, Hortobagyi G. Chemotherapy: what
progress in the last 5 years? J Clin Oncol 2005;23:
1760–75.
7. Higgins MJ, Wolff AC. Therapeutic options in the
management of metastatic breast cancer. Oncology
2008;22:614–23.
8. Ligibel JA, Winer EP. Trastuzumab/chemotherapy
combinations in metastatic breast cancer. Semin
Oncol 2002;29:38–43.
9. Kilburn LS. ‘Triple negative’ breast cancer: a new
area for phase III breast cancer clinical trials. Clin
Oncol 2008;20:35–9.
10. Kedar RP, Cosgrove DO, Smith IE, et al. Breast
carcinoma: measurement of tumor response to
PET-CT in Therapy 367
primary medical therapy with color flow Doppler
imaging. Radiology 1994;190:825–30.
11. Bolan PJ, Nelson MT, Yee D, et al. Imaging in breast
cancer: magnetic resonance spectroscopy. Breast
Cancer Res 2005;7:149–52.
12. Lehman CD, Schnall MD. Imaging in breast cancer:
magnetic resonance imaging. Breast Cancer Res
2005;7:215–9.
13. Tromberg BJ, Cerussi A, Shah N, et al. Imaging in
breast cancer: diffuse optics in breast cancer—de-
tecting tumors in pre-menopausal women and moni-
toring neoadjuvant chemotherapy. Breast Cancer
Res 2005;7:279–85.
14. Hylton N. MR imaging for assessment of breast
cancer response to neoadjuvant chemotherapy.
Magn Reson Imaging Clin N Am 2006;14:383–9.
15. Martincich L, Montemurro F, De Rosa G, et al. Moni-