Predicting Response to Neoadjuvant Chemotherapy Using 18F FDG PET-CT in Patients with Locally Advanced Breast Cancer.

OBJECTIVE: The study was aimed to find the utility of 18F FDG PET CT in assessing response to neoadjuvant chemotherapy (NACT) in female patients with locally advanced breast cancer (LABC). METHODS: All willing women with biopsy proven LABC, following clinical evaluation underwent baseline 18F FDG PET CT along with mammosonograpy and contrast enhanced computerized chest radiography (CECT). The response was assessed clinically before each cycle of chemotherapy using RECIST criteria. Those who were progressing clinically were offered alternate chemotherapy or radiation or surgery. Clinical responders were re-evaluated with 18F FDG PET CT, mammosonogram and CT chest before surgery. The pathological response as assed with residual cancer burden score was used as gold standard. RESULTS: Of the 30 women eligible, 26 women underwent repeat evaluation and surgery. The mean age was 49 years, 16 women were postmenopausal and 15 tumors were receptor positive. On final histopathology 15 % had completer response and 46 % were non responders. Using a cut off value of 50% of the baseline SUVmax, PET-CT had sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 64%, 75%, 75%, 65%, and 69%, respectively in differentiating pathological responders from non-responders. CONCLUSION: 18F FDG PET-CT predicted the response with greater accuracy than CT or clinical examination. Hence it can be used to identify non responders early in the course and alternate treatment can be offered to patients.

Whole-body 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) for staging locally advanced breast cancer: A prospective study from a tertiary cancer centre in south India.

Background & objectives: Locally advanced breast cancer (LABC) is associated with substantial risk of occult metastases. The patients with LABC have high rate of systemic relapse, suggesting inadequacy of the current conventional staging in detecting the occult metastatic spread. 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) is a new modality in the staging of breast cancer patients. Hence, this study was conducted to evaluate the role of 18F-FDG PET/CT in initial staging of LABC and to compare it with conventional methods. Methods: This prospective study included biopsy-confirmed female patients diagnosed with LABC meeting the selection criteria and attending surgical, medical and radiation oncology departments of a tertiary care centre in south India, from April 2013 to December 2014. Conventional workup included serum chemistry, mammogram, bone scan, contrast-enhanced CT (CECT) chest and upper abdomen and ultrasound abdomen and pelvis. All patients following conventional workup underwent 18F-FDG PET/CT. Results: In this study, 61 women with LABC underwent both conventional workup and 18F-FGD PET/CT. The 18F-FDG PET/CT, in comparison to conventional workup, revealed unsuspected N3 nodal disease in 11 more patients, revealed distant metastasis in seven more patients and also detected extra sites of metastasis in five patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT to detect distant metastasis were 95, 98, 95, 98 and 97 per cent, respectively, whereas the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional imaging to detect distant metastasis were 65, 93, 81, 84 and 84 per cent, respectively. Interpretation & conclusions: The 18F-FDG PET/CT was found to be more accurate than conventional imaging for staging and modified stage and treatment in 30 and 38 per cent of patients, respectively. It was particularly useful in detecting occult distant metastasis and N3 nodal disease with an added advantage of examining whole body in single session. However, CECT chest was superior over 18F-FDG PET/CT for detecting pulmonary metastasis.

Utility of [18F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG PET/CT) in the Initial Staging and Response Assessment of Locally Advanced Breast Cancer Patients Receiving Neoadjuvant Chemotherapy.

In India up to 50 % of breast cancer patients still present as locally advanced breast cancer (LABC). The conventional methods of metastatic work up include physical examination, bone scan, chest & abdominal imaging, and biochemical tests. It is likely that the conventional staging underestimates the extent of initial spread and there is a need for more sophisticated staging procedure. The PET/CT can detect extra-axillary and occult distant metastases and also aid in predicting response to chemotherapy at an early point in time. To evaluate the utility of FDG PET/CT in initial staging and response assessment of patients with LABC receiving NACT. A prospective study of all biopsy confirmed female patients diagnosed with LABC receiving NACT from April 2013 to May 2014. The conventional work up included serum chemistry, CECT chest and abdomen and bone scan. A baseline whole body PET/CT was done in all patients. A repeat staging evaluation and a whole body PET/CT was done after 2/3rd cycle of NACT in non-responders and after 3/4 cycles in clinical responders. The histopathology report of the operative specimen was used to document the pathological response. The FDG PET/CT reported distant metastases in 11 of 38 patients, where as conventional imaging revealed metastases in only 6. Almost all the distant lesions detected by conventional imaging were detected with PET/CT, which showed additional sites of metastasis in 3 patients. In 2 patients, PET/CT detected osteolytic bone metastasis which were not detected by bone scan. In 5 patients PET CT detected N3 disease which were missed on conventional imaging. A total of 14 patients had second PET/CT done to assess the response to NACT and 11 patients underwent surgery. Two patients had complete pathological response. Of these 1 patient had complete metabolic and morphologic response and other had complete metabolic and partial morphologic response on second PET/CT scan. The 18 FDG PET/CT can detect more number of metastasis as well as additional sites of metastasis compared to conventional methods. The response assessment resulted in change of treatment regimen in 14 % of patients.