Positron emission tomography imaging in evaluation of cancer patients.

Positron emission tomography (PET) is a diagnostic imaging technique that has progressed rapidly from being a research technique in laboratories to a routine clinical imaging modality. The most widely used radiotracer in PET is Fluorine18-fluorodeoxyglucose (F18-FDG), which is an analogue of glucose. The FDG uptake in cells is directly proportional to glucose metabolism of cells. Since glucose metabolism is increased many fold in malignant tumors PET has a high sensitivity and a high negative predictive value. PET with FDG is now the standard of care in initial staging, monitoring the response to the therapy, and management of lung cancer, colonic cancer, lymphoma, melanoma, esophageal cancer, head and neck cancer and breast cancer. Other indications of PET like bone tumor, ovarian cancer and cancer of unknown primary (CUP) has also been discussed in brief. The aim of this review article is to review the clinical applications of PET in various malignancies and only limited number of important studies will be discussed for this effort.

Sentinel lymph node biopsy in the management of breast cancer.

Sentinel node localization is the second most important development in this century after conservative lumpectomy for the treatment of early breast cancer. The sentinel node mapping is a new multidisciplinary approach for staging of axilla in an accurate and less morbid way as compared to axillary node dissection. Sentinel lymph node biopsy in patients with breast cancer has been adopted rapidly into clinical practice. The accuracy of sentinel lymph node biopsy is more than 95%, when performed meticulously (by an experienced multidisciplinary team) with proper patient selection. Sentinel lymph node biopsy is most widely used for both palpable and non-palpable T1 and T2 tumors. Recent studies show application of sentinel lymph node technique in patients with locally advanced breast cancer and after neoadjuvant chemotherapy. Therefore, sentinel lymph node biopsy technique has application in developing countries and other countries where screening for breast cancer is not common and most patients present relatively in advanced stage of the disease. Several aspects of the sentinel lymph node biopsy including technique, case selection, pathologic analysis and accuracy with supportive important studies published in the literature will be discussed in this review.