Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients

Neurologic Complications of Conventional Chemotherapy and Radiation Therapy

OBJECTIVE

Neurologic complications are among the most common and feared outcomes of cancer treatments. This review discusses the signs and symptoms, mechanisms, and management of the most common peripheral and central neurologic complications of chemotherapy, radiation therapy, and antiangiogenic therapy during cancer treatment and in survivors.

LATEST DEVELOPMENTS

The landscape of cancer treatments is evolving to include more targeted and biologic therapies, in addition to more traditional cytotoxic therapies and radiation therapy. With increasingly complex regimens and longer survival for patients with cancer, the early recognition and management of neurologic complications is key to improving the morbidity and mortality of patients living with cancer.

ESSENTIAL POINTS

Neurologists should be familiar with acute central and peripheral toxicities that can occur during cancer treatment and delayed toxicities that can occur years after exposure. Neurologists should be familiar with the clinical and radiologic presentations of these complications and strategies for management.

[Radiation induced brachial plexopathy: Diagnosis, risk factors, principles of care]

Radiation plexitis, also known as radiation-induced brachial neuropathy is a rare toxicity following axillary, breast, cervical or thoracic radiotherapy, first described in 1966 by Stoll and Andrew. Although improvements in radiotherapy techniques have greatly reduced its risk over the past seventy years, its severe form remains a dreaded complication that is difficult to manage in patients with increased life expectancy. This article summarizes the epidemiological elements, risk factors, diagnostic methods, doses and constraints to be respected in radiotherapy and the treatment strategies of radiation plexitis.

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Plexus and peripheral nerve metastasis

Cancer in the form of solid tumors, leukemia, and lymphoma can infiltrate and metastasize to the peripheral nervous system, including the cranial nerves, nerve roots, cervical, brachial and lumbosacral plexuses, and, rarely, the peripheral nerves. This review discusses the presentation, diagnostic evaluation, and treatment options for metastatic lesions to these components of the peripheral nervous system and is organized based on the anatomic distribution. As skull base metastases (also discussed in Chapter 14) result in cranial neuropathies, these will be covered in detail, as well as cancers that directly infiltrate the cranial nerves. Particular emphasis is placed on the clinical, imaging, and electrodiagnostic features that differentiate neoplastic plexopathies from radiation-induced plexopathies. Neurolymphomatosis, in which malignant lymphocytes invade the cranial nerves, nerve roots, brachial and lumbosacral plexuses, and peripheral nerves, is a rare manifestation of lymphoma and leukemia. Diagnoses of neurolymphomatosis are often missed or delayed given its varied presentations, resulting in poorer outcomes. Thus this disease will also be discussed in depth.

Metastatic Brachial Plexopathy with Brain and Spinal Metastasis in a Case of Recurrent Breast Carcinoma Demonstrated on 18F-FDG PET/CT

We report a case of a 56-year-old woman diagnosed with infiltrating ductal carcinoma of the left breast, who had undergone left modified radical mastectomy followed by radiotherapy and adjuvant chemotherapy. FDG PET-CT showed metastatic brachial plexopathy with intra-spinal and extra-axial brain metastasis. Metastatic brachial plexopathy along with brain and spinal metastasis is a rare condition with very less incidence. The scan also showed left para-sternal anterior chest wall recurrence with antero-superior mediastinal metastasis. 18FDG-PET scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy. It may also be useful in distinguishing between radiation-induced and metastatic plexopathy. Typical pattern of FDG uptake and dual time point imaging may increase specificity and require further evaluation.

Clinical Utility of (18)F-FDG PET/CT in brachial plexopathy secondary to metastatic breast cancer

Role of fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) in breast cancer is rapidly evolving. Brachial plexopathy is a rare clinical entity in follow-up of operated breast cancer patients, who presents with disease recurrence in the axilla. Conventionally, magnetic resonance imaging is the imaging modality of choice for diagnostic evaluation in these cases and only few case reports/short studies have explored the utility of PET/CT in this clinical indication. We present here a short case series to demonstrate the utility of PET/CT as an important adjunctive imaging modality to magnetic resonance to supplement diagnosis of brachial plexopathy, differentiate radiation-induced brachial plexopathy from neoplastic plexopathy, accurately restage the disease and to monitor response to chemotherapy.

Pelvic radiculopathies, lumbosacral plexopathies, and neuropathies in oncologic disease: a multidisciplinary approach to a diagnostic challenge

The purpose of this article is to familiarize the reader with the anatomy of the major pelvic nerves and the clinical features of associated lumbosacral plexopathies. To demonstrate this we illustrate several cases of malignant lumbosacral plexopathy on computed tomography, magnetic resonance imaging, and positron emission tomography/computed tomography. A new lumbosacral plexopathy in a patient with a prior history of abdominal or pelvic malignancy is usually of malignant etiology. Biopsies may be required to definitively differentiate tumour from posttreatment fibrosis, and in cases of inconclusive sampling or where biopsies are not possible, follow-up imaging may be necessary. In view of the complexity of clinical findings often confounded by a history of prior surgery and/or radiotherapy, a multidisciplinary approach between oncologists, neurologists, and radiologists is often required for what can be a diagnostic challenge.

Cortical plasticity induced by different degrees of peripheral nerve injuries: a rat functional magnetic resonance imaging study under 9.4 Tesla

BACKGROUND

Major peripheral nerve injuries not only result in local deficits but may also cause distal atrophy of target muscles or permanent loss of sensation. Likewise, these injuries have been shown to instigate long-lasting central cortical reorganization.

METHODS

Cortical plasticity changes induced after various types of major peripheral nerve injury using an electrical stimulation technique to the rat upper extremity and functional magnetic resonance imaging (fMRI) were examined. Studies were completed out immediately after injury (acute stage) and at two weeks (subacute stage) to evaluate time affect on plasticity.

RESULTS

After right-side median nerve transection, cortical representation of activation of the right-side ulnar nerve expanded intra-hemispherically into the cortical region that had been occupied by the median nerve representation After unilateral transection of both median and ulnar nerves, cortical representation of activation of the radial nerve on the same side of the body also demonstrated intra-hemispheric expansion. However, simultaneous electrical stimulation of the contralateral uninjured median and ulnar nerves resulted in a representation that had expanded both intra- and inter-hemispherically into the cortical region previously occupied by the two transected nerve representations.

CONCLUSIONS

After major peripheral nerve injury, an adjacent nerve, with similar function to the injured nerve, may become significantly over-activated in the cortex when stimulated. This results in intra-hemispheric cortical expansion as the only component of cortical plasticity. When all nerves responsible for a certain function are injured, the same nerves on the contralateral side of the body are affected and become significantly over-activated during a task. Both intra- and inter-hemispheric cortical expansion exist, while the latter dominates cortical plasticity.

Diagnosis of brachial and lumbosacral plexus lesions

To most doctors, brachial and lumbosacral plexopathies are known as difficult disorders, because of their complicated anatomy and relatively rare occurrence. Both the brachial, lumbar, and sacral plexuses are extensive PNS structures stretching from the neck to axillary region and running in the paraspinal lumbar and pelvic region, containing 100000-200000 axons with 12-15 major terminal branches supplying almost 50 muscles in each limb. The most difficult part in diagnosing a plexopathy is probably that it requires an adequate amount of clinical suspicion combined with a thorough anatomical knowledge of the PNS and a meticulous clinical examination. Once a set of symptoms is recognized as a plexopathy the patients' history and course of the disorder will often greatly limit the differential diagnosis. The most common cause of brachial plexopathy is probably neuralgic amyotrophy and the most common cause of lumbosacral plexopathy is diabetic amyotrophy. Traumatic and malignant lesions are fortunately rarer but just as devastating. This chapter provides an overview of both common and rarer brachial and lumbosacral plexus disorders, focusing on clinical examination, the use of additional investigative techniques, prognosis, and treatment.

F-18 FDG PET/CT for detection of malignant involvement of peripheral nerves: case series and literature review

PURPOSE

To evaluate the role of positron emission tomography plus computed tomography (PET/CT) scans in detecting malignant involvement of the peripheral nerves (PNs).

MATERIAL AND METHODS

We retrospectively reviewed medical records of all PET/CT studies performed at The University of Texas MD Anderson Cancer Center between 2003 and 2009, and selected patients in whom F-18 fluorodeoxyglucose (FDG) PET/CT findings were suspicious for malignant involvement of the PNs. We identified 26 cases of suspected tumorous involvement of the PNs that was subsequently confirmed by either biopsy or clinical follow-up. We evaluated the value of PET/CT in diagnosing malignant involvement of the PNs.

RESULTS

Of the 26 patients, 12 had lymphoma, 10 had breast cancer, 2 had lung cancer, 1 had colon cancer, and 1 had melanoma. In 21 patients, magnetic resonance imaging (MRI) was performed, either for follow-up of the PET/CT finding or to find an explanation for symptoms. MRI confirmed the presence of disease in only 9 patients, was interpreted as normal in 7 patients, and was inconclusive in 5 patients. FDG PET/CT was able to differentiate an active tumor from post-treatment fibrosis and could assess response to therapy with a high degree of confidence.

CONCLUSIONS

Our results indicate that FDG PET/CT is helpful in diagnosing malignant involvement of the PNs, especially when findings from anatomic imaging (MRI or CT) are negative. In cases of known treated malignancy involving the PNs, follow-up by PET/CT has the advantage of high sensitivity for local recurrence.

PET/CT and breast cancer

This paper summarises the current status of PET/CT in relation to breast cancer.

Neurotoxicity of radiation therapy

Direct or incidental exposure of the nervous system to therapeutic irradiation carries the risk of symptomatic neurologic injury. Central nervous system toxicity from radiation includes focal cerebral necrosis, neurocognitive deficits, and less commonly cerebrovascular disease, myelopathy, or the occurrence of a radiation-induced neoplasm. Brachial or lumbosacral plexopathy are the most common syndromes of radiation toxicity affecting the peripheral nervous system. This article focuses on the clinical features, diagnosis, and management options for patients with radiation neurotoxicity.

PET/CT in Radiation Therapy Planning for Breast Cancer

PET/computed tomography-based imaging is a valuable and useful test in the staging and restaging of breast cancer, especially in patients who have recurrent or locally advanced breast cancer. Its greatest clinical applications are in the detection and definition of the extent of recurrent or metastatic disease. However, the potential to improve radiation treatment planning by allowing for the tailoring of comprehensive radiation portals, particularly for locally advanced or recurrent breast cancer, makes it one of the most promising tools in the era of image-guided radiation therapy.

[Imaging of plexopathy]

Recent advances in magnetic resonance imaging (MRI) technology has improved vizualization of the peripheral nerve system, enabling further explorations of plexopathy beyond the physical examination and electrodiagnostic studies. High-resolution MRI is a method of choice, showing diffuse or focal enlargement, hyperintensity on T2-weighted images, altered fascicular patterns, enhancement after gadolinium injection or masses causing infiltration or compression, and signs of muscle denervation. Other techniques are complementary. Ultrasonography can depict a spectrum of lesions and can be coupled with dynamic manoeuvres to explore entrapment syndromes. Positron emission tomography (PET) can be helpful to differentiate between tumor recurrence and postradiation plexopathy. In posttraumatic brachial plexopathy, postmyelographic tomography and MRI are complementary. Traumatic injury, tumor formation, entrapment syndrome, and other conditions illustrate the different techniques available for imaging. Adequate imaging of the brachial and lombosacral plexuses is a useful aid for diagnosis, preoperative assessment and therapeutic planning and follow-up.

Management of brachial plexus region tumours and tumour-like conditions: relevant diagnostic and surgical features in a consecutive series of eighteen patients

BACKGROUND

Tumours of the brachial plexus region are rare and most publications are case reports or studies with a small series of patients. The aim of this study is to present our experience in managing these lesions.

METHODS

We review 18 patients with tumours in the brachial plexus region submitted to surgical treatment in a 6 year period, including their clinical presentation, neuro-imaging data, surgical findings and outcome.

FINDINGS

The tumours comprised a heterogeneous group of lesions, including schwannomas, neurofibromas, malignant peripheral nerve sheath tumour (MPNST), sarcomas, metastases, desmoids and an aneurysmal bone cyst. The most common presentation was an expanding lump (83.33%). Eleven tumours were benign and 7 were malignant. Neurofibromatosis was present in only 2 patients (11.11%). Gross total resection was achieved in 14 patients and sub-total resection in the others. Only 3 patients presented with new post-operative motor deficits. The incidence of complications was low (16.5 %).

CONCLUSIONS

The majority of tumours were benign and most of them could be excised with a low incidence of additional deficits. Some of the malignant tumours could be controlled by surgery plus adjuvant therapy, but this category is still associated with high morbidity and mortality rates.

Nerve transfer for elbow flexion in radiation-induced brachial plexopathy: a case report

Radiation-induced brachial plexopathy is an uncommon but devastating late complication seen in patients receiving radiation therapy to the chest wall and axilla. Treatment options are unfortunately limited. We report a case of a 59-year-old woman treated with radiation therapy for breast cancer 12 years earlier, who presented with loss of elbow flexion and marked shoulder weakness. Electromyogram and intraoperative stimulation of the musculocutaneous nerve branches were consistent with a proximal motor nerve conduction block. Microsurgical transfer of median and ulnar nerve fascicles to the biceps and brachialis branches of the musculocutaneous nerve, respectively, were performed. The patient recovered MRC grade 4/5 elbow flexion after surgery. The characteristics of this disorder and surgical treatment options are reviewed.

Partial ulnar nerve transfer to the nerve to the biceps for the treatment of brachial plexopathy in metastatic breast carcinoma: case report

Brachial plexus neuropathy can cause progressive pain and disability in patients with breast cancer. Metastatic spread and radiation injury are the most common causes in these patients. We report a case of partial ulnar nerve transfer to the nerve to the biceps muscle to restore elbow flexion in a patient with combined radiation-induced and metastatic brachial plexopathy.

Diagnosis of Recurrent and Metastatic Disease Using F-18 Fluorodeoxyglucose-Positron Emission Tomography in Breast Cancer

One of the major strengths of F-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) in breast cancer imaging is in the evaluation of patients who have suspected loco-regional recurrence or distant metastasis. In general, FDG-PET is more sensitive than conventional imaging for the detection of recurrent disease. Because of its ability to more accurately stage patients who have advanced breast cancer, FDG-PET has a significant impact on choice of treatment and management in this patient group.

Causes of lumbosacral plexopathy

The lumbosacral plexus represents the nerve supply to the lower back, pelvis and legs. This review will focus on diseases and disorders affecting the pathway as demonstrated by magnetic resonance imaging (MRI) and computed tomography (CT). We stress the need to review the lumbosacral plexus in patients with non-specific symptoms such as back, hip, pelvic pain, and in those who present with sciatica unaccompanied by demonstrable intervertebral disc prolapse. We illustrate that the imaging appearances may be non-specific and re-inforce the importance of the clinical history and the use of tissue sampling to achieve an accurate diagnosis.

Peripheral nervous system involvement in patients with cancer

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

Current and future use of positron emission tomography (PET) in breast cancer

Positron emission tomography (PET) is a radiotracer imaging method that is increasingly used in both the clinical care of breast cancer patients and in translational breast cancer research. This review emphasizes current and future clinical applications of PET to breast cancer, and highlights some translational research using PET to elucidate the clinical biology of breast cancer. PET principles are reviewed, followed by a review of current applications of (18)F-fluorodeoxyglucose (FDG) to clinical breast cancer care. Finally we review work done with other radiopharmaceuticals beyond FDG designed to image a number of aspects of breast cancer biology, emphasizing those most likely to enter clinical trials in the near future.

[Contribution of positron emission tomography to the detection and staging of breast cancer]

INTRODUCTION

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is a diagnostic imaging tool with multiple applications in oncology. One of the more promising applications in breast cancer is noninvasive lymph node staging and detection of distant metastases, which may provide useful information about prognosis and treatment response.

MATERIAL AND METHOD

Published studies on FDG-PET applications in breast cancer detection and staging were reviewed. We also present our own experience in patients referred for preoperative staging of breast cancer.

RESULTS

FDG-PET is very useful in evaluating dense breasts, multicentric disease and breast prostheses. The sensitivity of FDG-PET for nodal staging is low, and consequently it cannot replace either sentinel lymph node biopsy or histologic examination. However, it is more accurate than another noninvasive techniques and is very useful in internal mammary node chain evaluation. FDG-PET can improve and maybe replace conventional imaging in detecting metastatic disease, especially in high risk patients with locoregionally advanced recurrent breast cancer or increased serum tumor markers, and helps to characterize unclear findings of anatomic imaging techniques or scintigraphy.

CONCLUSIONS

FDG-PET is useful in breast cancer staging. It complements and even improves information from other diagnostic techniques and changes therapeutic management in a high proportion of patients.

Metastases to the peripheral nervous system

Cancer metastasis can affect any part of the nervous system. When the peripheral nervous system is involved, the usual targets are cranial nerves, nerve roots and plexi. However, peripheral nerves and muscles can also be affected by compression or infiltration of neoplastic cells. This review focuses in the diagnosis and treatment of metastatic complications of cancer involving plexi, peripheral nerves and muscles.

Imaging in breast cancer: Single-photon computed tomography and positron-emission tomography

Although mammography remains a key imaging method for the early detection and screening of breast cancer, the overall accuracy of this test remains low. Several radiopharmaceuticals have been proposed as adjunct imaging methods to characterize breast masses by single-photon-emission computed tomography (SPECT) and positron-emission tomography (PET). Useful in characterizing indeterminate palpable masses and in the detection of axillary metastases, these techniques are insufficiently sensitive to detect subcentimetric tumor deposits. Their role in staging nodal involvement of the axillary areas therefore currently remains limited. Several enzymes and receptors have been targeted for imaging breast cancers with PET. [¹⁸F]Fluorodeoxyglucose is particularly useful in the detection and staging of recurrent breast cancer and in assessing the response to chemotherapy. Several other ligands targeting proliferative activity, protein synthesis, and hormone and cell-membrane receptors may complement this approach by providing unique information about biological characteristics of breast cancer across primary and metastatic tumor sites.

The Value of FDG Positron Emission Tomography in the Management of Patients with Breast Cancer

Increasing experience with positron emission tomography (PET) scanning in breast cancer patients is revealing a significant role for this imaging modality. This report summarizes the experience of 2-[F18]fluoro-2-deoxy-D-glucose (FDG) PET scanning in 165 breast cancer patients from the BC Cancer Agency, British Columbia, Canada, and reviews the literature on this topic. Using the database at PETSCAN Vancouver, we identified imaged patients with a diagnosis of breast cancer. We then conducted a retrospective review of these patients' BC Cancer Agency charts to extract demographic and follow-up information. Between November 2000 and March 2003 we identified 165 patients with histologically confirmed breast cancer who had undergone PET scanning, were registered at the BC Cancer Agency, and had follow-up information. The median patient age was 52 years. The sensitivity of PET in detecting axillary metastases was 28%, and the specificity was 86%. At diagnosis, 5% of patients were diagnosed with distant metastases. In patients undergoing PET scanning because of suspected recurrence, the sensitivity and specificity for detecting recurrence were 89% and 88%, respectively. Distant metastases were demonstrated in 30% of patients who were thought only to have local-regional recurrence. The results suggest that there are two clinical situations in which PET appears to be particularly valuable. The first is in the evaluation of patients who are suspected of having a tumor recurrence. The other is in identifying patients with multifocal or distant sites of malignancy who otherwise appear to have an isolated, potentially curable, local-regional recurrence.

Evolving role of positron emission tomography in breast cancer imaging

18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has been used for detection, staging, and response monitoring in breast cancer patients. Although studies have proven its accuracy in detection of the primary tumor and axillary staging, its most important current clinical application is in detection and defining the extent of recurrent or metastatic breast cancer and for monitoring response to therapy. PET is complementary to conventional methods of staging in that it provides better sensitivity in detecting nodal and lytic bone metastases; however, it should not be considered a substitute for conventional staging studies, including computed tomography and bone scintigraphy. FDG uptake in the primary tumor carries prognostic information, but the underlying biochemical mechanisms responsible for enhanced glucose metabolism have not been completely elucidated. Future work using other PET tracers besides FDG will undoubtedly help our understanding of tumor biology and help tailor therapy to individual patient by improving our ability to quantify the therapeutic target, identify drug resistance factors, and measure and predict early response.

PET and functional anatomic fusion imaging in lung and breast cancers

Metabolic imaging with PET is an established adjunct to anatomic imaging methods in patients with bronchial and breast cancers. The functional anatomic fusion imaging with PET/CT can further improve staging and restaging of patients. PET/CT can influence the planning of a surgical intervention or radiation treatment at staging and in patients with suspected locoregional recurrence. The use of a PET/CT whole body imaging protocol may identify extended disease earlier than conventional imaging methods and thus influence treatment decisions.

Fluorodeoxyglucose-PET in the management of breast cancer

FDG-PET can be helpful in the diagnosis of primary breast cancer, especially in patients with dense breast tissue, significant fibrocystic changes, fibrosis after radiotherapy, and inconclusive results from MR imaging and other imaging modalities. PET has a limited role in patients with very small tumors and with well-differentiated and lobular types of breast cancer. In preoperative staging, FDG-PET has a low sensitivity for detection of regional lymph node involvement. Also, current PET imaging techniques can easily miss micrometastases. FDG-PET, however, has high positive predictive value for the axillary lymph node involvement, especially patient with advanced tumors. Compared with conventional imaging modalities, FDG-PET provides high diagnostic accuracy in detecting recurrent or metastatic breast carcinoma. FDG-PET seems to be highly useful for monitoring response to therapeutic interventions. This technique can identify response to therapy earlier than any other imaging method currently available. Obviously, identification of nonresponding patients could greatly improve patient management by allowing termination of ineffective and toxic therapies.

Positron emission tomography in the staging and management of breast cancer

Background

Breast cancer is the commonest cause of cancer death in women in the Western world, and imaging is essential in its diagnosis and staging. Metabolic imaging is a novel approach to improving the detection of cancers, as malignant transformation of cells is often associated with increased metabolic activity. This review assesses the possible role of positron emission tomography (PET) as a single non-invasive imaging modality to replace or complement current imaging and surgical practices in the diagnosis and staging of breast cancer.

Methods and results

A Medline search was performed and articles were cross-referenced with other relevant material. Evaluation of primary breast cancer with PET has shown a sensitivity of between 64 and 100 per cent and a specificity of 33–100 per cent; diagnostic accuracy appears to be related to tumour size. Difficulties arise in altered fluorodeoxyglucose uptake in lobular carcinoma, carcinoma in situ and benign inflammatory breast disease. In axillary staging, sensitivities of between 25 and 100 per cent have been reported, but with a false-negative of up to 20 per cent. In the assessment of distant metastasis and asymptomatic patients with raised levels of tumour markers, PET was superior to conventional imaging modalities.

Conclusion

PET is not a single diagnostic and staging tool that can replace current surgical, histological and radiological staging. Its main role in breast cancer lies in the investigation of metastatic disease and the evaluation of pathological response to various chemotherapeutic regimens.

Molecular imaging in breast cancer

Since the 1960s, bone scanning has played a major role in the management of breast cancer. In the last decade, however, the role of radionuclide molecular imaging has expanded significantly in the clinical management of breast cancer because of fluorodeoxyglucose positron emission tomography, mammoscintigraphy, and sentinel lymph node techniques. Molecular imaging also is instrumental in drug development,gene therapy, and in basic science research of breast cancer. This article provides a comprehensive review of the role of molecular imaging of breast cancer in clinical practice and reports on the current state of research in this field.