FDG PET-CT for solitary pulmonary nodule and lung cancer: Literature review.

The investigation of solitary pulmonary nodule (SPN) and non-small cell lung cancer (NSCLC) has rapidly become one of the main indications for 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), currently combined with computed tomography (PET-CT). In this literature review, we first attempt to clarify how PET imaging contributes to investigating SPN, in conjunction with conventional CT. We highlight the prospects of research underway to improve our understanding of SPN. In the second part of this review, we analyze the current role of PET-CT in the overall care process for lung cancer. We review the indications for which consensus has been reached, for example initial staging, as well as new indications such as radiation therapy planning or prognostic assessment.

Prognostic impact of 18F-FDG PET/CT staging and of pathological response to neoadjuvant chemotherapy in triple-negative breast cancer.

PURPOSE: Mortality is high in patients with locally advanced triple-negative breast cancer (TNBC), especially in those with residual tumour after neoadjuvant chemotherapy (NAC). The aim of this study was to determine if pretreatment (18)F-FDG PET/CT staging and pathological findings after NAC could together allow stratification of patients into prognostic groups. METHODS: Initial staging with (18)F-FDG PET/CT was performed prospectively in 85 consecutive patients with stage II/III TNBC. Correlations between PET findings and disease-specific survival (DSS) were examined. In patients without distant metastases on PET staging, the impact of pathological response to NAC on DSS was examined. Patterns of recurrence were also analysed. RESULTS: (18)F-DG PET/CT revealed distant metastases in 11 of 85 patients (12.9 %). Among 74 M0 patients, 23 (31.1 %) showed a pathological complete response (pCR) at surgery, while 51 had residual invasive disease (no pCR). DSS differed considerably among the three groups of patients (log-rank P < .001): among patients with occult metastases on baseline PET/CT, 2-year DSS was 18.2 %, and among patients without initial metastases on PET/CT, 5-year DSS was 61.3 % in patients without pCR after NAC and 95.2 % in those with pCR. Of the 51 patients who did not achieve pCR, 21 relapsed (17 developed distant metastases). The sites of distant recurrence were: lung/pleura (nine patients), brain (eight patients), liver (six patients), distant lymph nodes (six patients) and bone (five patients). CONCLUSION: In patients with clinical stage II/III TNBC, (18)F-FDG PET/CT findings at initial staging and pathological response at the end of NAC allow three groups of patients with quite different prognoses to be defined. Extraskeletal recurrences predominated. Specific follow-up strategies in patients with TNBC who do not achieve pCR deserve investigation.

HER2-overexpressing breast cancer: FDG uptake after two cycles of chemotherapy predicts the outcome of neoadjuvant treatment.

BACKGROUND: Pathologic complete response (pCR) to neoadjuvant treatment (NAT) is associated with improved survival of patients with HER2+ breast cancer. We investigated the ability of interim positron emission tomography (PET) regarding early prediction of pathology outcomes. METHODS: During 61 months, consecutive patients with locally advanced or large HER2+ breast cancer patients without distant metastases were included. All patients received NAT with four cycles of epirubicin+cyclophosphamide, followed by four cycles of docetaxel+trastuzumab. ¹8F-fluorodeoxyglucose (¹8F-FDG)-PET/computed tomography (CT) was performed at baseline (PET1) and after two cycles of chemotherapy (PET2). Maximum standardised uptake values were measured in the primary tumour as well as in the axillary lymph nodes. The correlation between pathologic response and SUV parameters (SUVmax at PET1, PET2 and ΔSUVmax) was examined with the t-test. The predictive performance regarding the identification of non-responders was evaluated using receiver operating characteristics (ROC) analysis. RESULTS: Thirty women were prospectively included and 60 PET/CT examination performed. At baseline, 22 patients had PET+ axilla and in nine of them ¹8F-FDG uptake was higher than in the primary tumour. At surgery, 14 patients (47%) showed residual tumour (non-pCR), whereas 16 (53%) reached pCR. Best prediction was obtained when considering the absolute residual SUVmax value at PET2 (AUC=0.91) vs 0.67 for SUVmax at PET1 and 0.86 for ΔSUVmax. The risk of non-pCR was 92.3% in patients with any site of residual uptake >3 at PET2, no matter whether in breast or axilla, vs 11.8% in patients with uptake ≤3 (P=0.0001). The sensitivity, specificity, PPV, NPV and overall accuracy of this cutoff were, respectively: 85.7%, 93.8%, 92.3%, 88.2% and 90%. CONCLUSION: The level of residual ¹8F-FDG uptake after two cycles of chemotherapy predicts residual disease at completion of NAT with chemotherapy+trastuzumab with high accuracy. Because many innovative therapeutic strategies are now available (e.g., addition of a second HER2-directed therapy or an antiangiogenic), early prediction of poor response is critical.

Breast inflammation: indications for MRI and PET-CT.

Breast MRI should not be used for differential diagnosis between inflammatory breast cancer and acute mastitis (AM) prior to treatment. When mastitis symptoms persist after 10 to 15 days of well-managed medical treatment, MRI may be performed in addition to an ultrasound examination, a mammogram and to taking histological samples, in order to eliminate inflammatory breast cancer (IBC). For staging, MRI would seem to be useful in looking for a contralateral lesion, PET-CT for finding information about remote metastases and in certain centres, for information about the initial extension to local/regional lymph nodes, which would guide the fields of irradiation (since patients can become lymph node negative after neoadjuvant chemotherapy). MRI and PET-CT seems to be useful for early detection of patients responding poorly to neoadjuvant chemotherapy so that the latter may be rapidly modified.

[PET-CT for evaluation of the solitary pulmonary nodule: an update]. / TEP-TDM pour l'exploration du nodule pulmonaire solitaire: acquis et perspectives.

INTRODUCTION: Positron emission tomography (PET) with 18F-FDG has become an important tool for the characterization of solitary pulmonary nodules (SPN). BACKGROUND: The results of the main meta-analyses show that the sensitivity and specificity of 18F-FDG PET for determining malignancy of SPN are close to 95% and 80% respectively. The limits of the technology are now well known. False negative results are mainly due to certain histological types with low metabolic activity (such as bronchiolo-alveolar carcinoma and typical carcinoid), or small size (nodules less than 8 mm). False positives are mainly represented by granulomatous and infectious processes. VIEWPOINTS: A gain in accuracy occurred with the advent of hybrid PET/CT machines that combine the functional data from 18FDG-PET and the morphological data of computed tomography. Improved imaging protocols (eg. injection of iodinated contrast media) could further enhance the performance of PET-CT. Further improvements will rely on respiratory synchronization protocols and on the advent of new PET tracers. CONCLUSION: 18F-FDG PET-CT should be performed for any nodule over 8 mm in size when the pre-test probability of malignancy is not deemed negligible.

[PET/CT in breast cancer: an update]. / Différents rôles de la TEP-TDM en sénologie : mise au point.

The authors discuss the various roles of 18F-FDG PET/CT in the management of breast cancer. Roles of new tracers such as F-18 fluoro-L-thymidine (a marker of cell proliferation), 18-fluoro-17-B-estradiol (marker of estrogen receptor) and sodium fluoride (marker of bone matrix) are also mentioned. There is little justification for the use of FDG-PET/CT in patient with clinically T1 (< or = 2 cm) N0 tumours. Notably, it cannot be used as a substitute to SLNB "sentinel lymph node biopsy" for axillary staging due to limited sensitivity for the detection of small metastases. The case is different in higher risk patients, and especially so in patients with locally advanced disease. FDG-PET/CT in these patients might depict lymph node involvement in the level III of Berg or in supraclavicular or internal mammary basins. It might also uncover occult distant metastases, notably, early osteomedullary infiltration. Thus, for these tumors, initial PET/CT can enable better intramodality treatment planning or a change in treatment. PET/CT as a whole-body examination is also very efficient in case of suspicion of recurrence. On the other hand, many studies show that this functional imaging could be used to assess early response to neoadjuvant chemotherapy or to chemotherapy of metastatic disease. 18FDG-PET/CT could thus become an unavoidable modality to answer various clinical situations.

[Sentinel node biopsy in breast cancer]. / La technique du ganglion sentinelle dans le cancer du sein: quelques considérations récentes.

As compared to conventional axillary dissection, the sentinel node technique is accompanied by reduced morbidity and shorter hospital stay. Based on available data, the use of this technique does not seem to yield higher rates of axillary recurrence. A combination of both radioisotope detection and blue dye increases the identification rate, while also reducing false-negative rate. Surgical results are optimized when preoperative lymphoscintigraphy mapping is obtained in addition to peroperative probe detection. Considering the site of injection, the subareolar injection can be easy to apply even in case of non-palpable tumours, and gives higher count rates. However, the intraparenchymal, peritumoral, injection is necessary to evidence cases of extra-axillary drainage (internal mammary, infra- or supraclavicular) that is present in about 20% of patients. With the advent of hybrid cameras (SPECT-CT), the topography of these extra-axillary nodes can be given with high precision. Use of the sentinel node technique has been accompanied by an increase in the percent of patients with node involvement, due to an increased detection of micrometastases inferior or equal to 2 mm. Following an overview of basic principles, and of the main results with the sentinel node technique we focus the discussion on several points that are still open to debate, such as: 1) which group of patients can benefit from the sentinel node technique? 2) What is the optimal methodology? 3) What is the prognostic significance of micrometastases and of isolated tumour cells? 4) What attention should be given to extra-axillary drainage?

[Advantages of PET-CT in the work-up of cervical cancer]. / Intérêts de la TEP-TDM pour le cancer du col de l'utérus.

The present paper addresses the advantages and limits of PET-CT in the work-up of cervical cancer. PET-CT is not to be overlooked in initial staging. It is useful to assess involvement of pelvic and lumbar lymph nodes. It can improve staging accuracy and help guide initial treatment such as optimisation of radiation therapy fields. Given its limited spatial resolution however, PET does not seem so adequate to document tumours less than 5 mm in diameter. It is not warranted for staging carcinoma in situ (FIGO stage 0) or preclinical carcinoma (FIGO stage 1A1 and 1A2). Furthermore MRI performances are best as far as local extension and tumour volume measurement are concerned. PET brings prognostic information. High initial uptake in tumour tissue or persistent increased uptake at completion of treatment indicates rather poor prognosis. PET is useful to evaluate therapy, but its exact role in this issue remains to be further refined. Finally, PET-CT can document early recurrence of disease.