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NLN Position Papers: Risk Reduction, Diagnosis and Treatment, Exercise, Air Travel, Training, Breast Cancer Screening
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Volume 24, No. 1 January - March, 2012
Exercise for breast cancer survivors: Prevention, treatment, and attenuation of persistent adverse effects of treatment. including lymphedema?
Volume 23, No. 4 October - December, 2011
Imaging Lymphatic Disorders
Volume 23, No. 4 October - December, 2011
What is SPECT?
Exercise is good for breast cancer survivors, for many reasons. Multiple large, methodologically strong observational studies consistently find that three hours a week or more of walking reduces risk for breast cancer recurrence or mortality. There have been over 50 high quality randomized controlled trials which have demonstrated the safety and benefits of exercise during and after breast cancer treatment. The demonstrated benefits include physiologic improvements in physical function, cardiorespiratory fitness, strength, body weight, and body composition. Additional benefits include improvements in cancer-related symptoms and side effects, fatigue, and body image. Based on these findings, last year the American College of Sports Medicine published a set of recommendations for exercise among cancer survivors, including breast cancer survivors. The advice from the ACSM begins with 2 words 'Avoid Inactivity', and continues with guidance to return to normal daily activities as soon as possible after surgery and during non-surgical treatments. The specific recommendation for aerobic activity is to build to 150 minutes per week over the course of a month. Advice for cancer survivors to do flexibility activities on a daily basis mirrors long-held advice from physical therapists and certified lymphedema therapists. Resistance training is recommended 2-3 times weekly. These ACSM recommendations are similar to exercise advice from the National Lymphedema Network, the MacMillan Report from the U.K., and guidelines from Canada and Australia.
The ACSM expert roundtable advised that breast cancer survivors start with a supervised upper body resistance training program and that if a woman notices a change in symptoms that lasts a week or longer, she should seek an evaluation from a medical professional with training in lymphedema. The roundtable noted that the fitness professionals leading programs for cancer survivors should be familiar with common toxicities of cancer treatment (including lymphedema). The ACSM offers such training through the Cancer Exercise Trainer webinars. There is also a specialty certification for personal trainers through ACSM called 'Cancer Exercise Trainer'. Pre-exercise evaluation was advised only for those women with upper body symptoms. Those who had diagnosed upper body issues, including but not limited to lymphedema, were advised to seek treatment for those issues prior to starting upper body exercise. Those who developed new upper body symptoms, including but not limited to lymphedema symptoms, were advised to reduce upper body exercise and seek evaluation and treatment for those issues prior to restarting.
The advice from the ACSM is much more specific than any prior published advice on this topic, yet many elements of translating this advice to safe, effective, easily available, low cost exercise programs remain to be clarified and prepared. A group of us are undertaking that work, revising the PAL trial intervention so that it will remain safe and efficacious but will be more feasible to implement within a wide variety of settings, including large cancer centers, community oncology clinics, free-standing private physical therapy clinics, as well as community fitness facilities with adequately trained fitness personnel. The barriers to getting this program into the hands of as many of survivors as possible are formidable. There is no existing infrastructure for providing the program. Oncology clinicians are generally enthusiastic about the program and hope their patients will participate. However, getting oncology clinicians to refer women into the program is challenging, given that they are already so overburdened with other important clinical issues with their patients and how little time they get with patients.
The revised program, firmly grounded in the PAL trial intervention, is currently being called 'Strength After Breast Cancer' or 'Strength ABCs'. We renamed it because of concerns that women without lymphedema would see the name 'Physical Activity and Lymphedema' and decide, 'that's not for me'. The revised program starts with a physical therapy evaluation in which a certified lymphedema therapist (CLT) determines whether the survivor can safely proceed to doing a group weight training class or needs one-on-one therapy to reduce lymphedema, rotator cuff impingements and the myriad of other issues present in breast cancer survivors. It is hoped that most can proceed to the group exercise sessions eventually, even if one-on-one therapy is needed first. Regardless of the outcome of the evaluation, all survivors are invited to attend a 1-hour educational lecture in a group setting based on NLN's widely available patient education materials (training of certified lymphedema therapists, exercise, risk reduction guidelines, air travel).
For those cleared for group exercise, Strength ABCs then proceeds with four group exercise sessions to teach the PAL weight training protocol. At the end of the program, women are given a kitchen magnet that reminds them of key factors that will influence the long term effectiveness of the program, including that if they have a change in symptoms that lasts a week or longer, they should call to set up an evaluation for possible onset or flare-up. The educational lecture and group exercise sessions could be led by physical therapists, lymphedema therapists, or fitness professionals with specialty training in cancer and exercise. Program reimbursement and out-of-pocket cost issues differ across PTs versus CLT versus fitness professionals. Scheduling challenges also vary across PTs and CLTs versus fitness professionals. The breast cancer survivors who participate choose in advance whether they will exercise at home with adjustable dumbbells or at a local gym near their homes. The exercises taught vary according to this choice. In our ongoing research study, we are recruiting 120 women participants to evaluate whether this revised program is as safe and effective as the PAL trial intervention. We are seeking funding to create an online marketing and tracking tool for breast cancer survivors who participate.
Many of us share the goal of making it possible for as many of the 2.6 million breast cancer survivors in the U.S. as possible to have easy access to safe, effective exercise interventions that will improve their health and well-being. Lymphedema is only one of multiple reasons these women need to exercise but it may be a significant motivator. The barriers to getting any group of people exercising regularly are numerous. Breast cancer survivors may be particularly wary of exercise because for decades, oncology clinicians advised breast cancer patients to 'rest, take it easy, don't push yourself'. Advice to avoid overuse, injury, or trauma to the upper body on the side that received treatment is still prevalent and often still interpreted as avoiding use of the upper body on the side that received treatment. This is an excuse women use to avoid any kind of exercise. How many women do you know who would happily conclude that advice to avoid one specific type of exercise is advice to be sedentary? But we know exercise is good for survivors, so how do we get them moving? Do we think that telling them it might reduce risk for breast cancer specific mortality will make more women willing to pay for exercise programs, good walking shoes, and actually take the time for the recommended 3 hours a week of walking? Unfortunately, we know from four decades of efforts to motivate people to exercise because it will reduce likelihood of a disease that might happen years or decades from now results in little to no behavior change. We know that short term goals are more effective than long term goals for behavior change. Most of us are familiar with the idea of 'SMART' goals: specific, measurable, attainable, relevant, and time bound. This has relevance for breast cancer survivors with and at risk for lymphedema because if women have a specific goal to limit lymphedema onset or worsening and can be educated to understand their risk for lymphedema onset and progression, they may be motivated to do something about it through measurable, attainable, relevant, and time-bound exercise programs. If there is an intervention which can control lymphedema onset or progression, they might be particularly motivated to engage in that activity.
As we undertake the arduous work of translating the results of upper body exercise research trials into programs that are available to as many of the 2.6 million breast cancer survivors in the U.S. as possible, there will be questions to answer and decisions to make. As we do so, I urge all of us to weigh carefully the risks of remaining inactive and the resulting de-conditioning against the risks of slowly progressive weight-lifting.
Lymphedema (LE) develops from an imbalance between the generation and removal of interstitial fluid and proteins. Swelling results when the lymphatic system fails to remove interstitial fluid at the rate it is accumulating. Although lymphedema is primarily a clinical diagnosis, modern imaging can identify features of the disorder that can not be easily discerned by clinical examination. They permit interrogation of the anatomic and pathophysiologic processes underlying the disorder.
Diagnostic Imaging in Lymphedema
Dramatic advances in medical imaging have occurred over the last 20 years. All the common imaging modalities have been applied to the evaluation of patients with lymphedema. Oil Contrast Lymphography was the original imaging technique for evaluating the lymphatic system and it continues to be utilized occasionally for identification and demonstration of lymphatic channels, such as in preoperative planning.
Ultrasound:
Ultrasound is useful for the evaluation of deep venous thrombosis, determination of tissue consistency, and measurement of epifascial depth as a quantitative index of edema. In unexplained edema of the legs, duplex ultrasound examination of the venous system is mandatory for patient management. Duplex ultrasound with high frequency probe (10-20MHz) is a reliable and objective way to image the complex lymphedema areas (e.g. of breast, axilla, or back) and various anatomical abnormalities in addition to venous and arterial hemodynamics. The efficacy of lymphedema treatment may be assessed with duplex ultrasound evaluation measuring the epifascial hypoechogenic space.
Computerized Tomography (CT):
The utility of CT images in lymphedema derives from the exquisite anatomic detail as well as information about fluid content of tissues that they provide. If iodinated contrast is injected, they also provide information about tissue permeability to water soluble molecules. In lymphedema, CT can reveal structural or mechanical causes of lymphatic obstruction such as tumors, synovial cysts, or other mass lesions. This can be particularly useful within the chest, abdomen, or pelvis. Even without intravenous contrast, they often display subtle differences in tissue density resulting from edema.
Magnetic Resonance Imaging (MRI):
MRI images demonstrate fluid as well as anatomic detail in addition to subcutaneous edema, reticular lymphangiectasis (pathological dilatation of lymph vessels), lymph cysts and lakes, and dilated lymph channels. MRI can visualize peripheral lymph trunks, lymph nodes, and soft tissue. However, lymphoscintigraphy is more helpful in addressing the functional status of lymphatic obstruction. Using these two imaging modalities together is helpful for anatomical diagnosis and delineating the disarranged pattern of lymphedema.
Swollen subcutaneous tissue reveals low signal intensity on T1-weighted image (water/ fat is dark) and high signal intensity on T2-weighted images (water/fluid is white). Short-TI-IR (STIR) images are useful for evaluation of trabecular structures and fluid collections in the subcutaneous tissue with high signal contrast as well as for evaluation of lymphedema. Among its many uses in patients with edema include: localization of lymphedema to subfascial or epifascial compartments, demonstration of enlarged lymph vessels, and identification of structural causes of edema as with CT.
Lymphoscintigraphy (LS):
Although widely employed for sentinel node localization, LS is also very useful for evaluating (LE) and other lymphatic disorders. Examples include differentiation of primary, secondary and venous lymphedema, and other lymphatic etiologies. LS is indicated in evaluation of edema of unclear etiology for clarification of therapy guidance. Undiagnosed or untreated LE is associated with progressive disease, recurrent infections, and resistance to therapy. Congenital LE is variable in time of onset and severity, and increases surgical risk. Therefore, early and accurate diagnosis of the condition is important.
Cutaneous (skin) or subcutaneous (layer under skin) injection is followed by mild exercise of the limbs and/or ambulation. Images are usually acquired in whole body format at ~15-20 minutes, at ~2-3 hours, and sometimes the next day. The radiation dose to the patient is low from the small doses of Tc99m that are employed.
Normal lymphoscintigraphy demonstrates prompt flow to regional nodes by 15–20 min. in discrete, nontortuous lymphatics. Images at 2-3 hr. depict fairly intense nodal uptake, with some uptake in liver and spleen. Abnormal findings include slow or no flow, tortuous or deviated channels, collateral or crossover flow, localized or diffuse dermal retention. Areas of inflammation or infection usually reveal increased retention of radiotracer, as a reflection of macrophage (scavenge cells) activation, increased numbers of phagocytic cells (ingest microorganisms and foreign particles), and regional stasis and edema with delayed clearance of interstitial fluid.
Summary and Conclusions:
Lymphedema, in most cases, is established by history and detailed physical examination. It can also be evaluated with ultrasound of the epifascial compartment and demonstrated with MRI and CT. The severity of lymphatic functional deficits and mapping of lymph drainage can be evaluated with lymphoscintigraphy. Lymphatic imaging plays a pivotal role in defining the etiology and therapy of lymphedema. Lymphedema is a treatable disorder, and early recognition and treatment should be promulgated.
What is SPECT?
Single-photon emission computed tomography (SPECT) is a common nuclear medicine technique that allows for three dimensional (3D) visualization of imaging targets. 3D images are acquired by rotating a gamma camera (a camera that detects radioactivity) 360? around a patient after injection of a radiolabeled tracer molecule. Many different radiolabeled tracers can be utilized to evaluate the cardiac, renal, endocrine, or lymphatic, systems, among others. To image the lymphatic system, technetium labeled sulfur colloid is generally utilized since sulfur colloids are large molecules that are preferentially absorbed by the lymphatic rather than the venous capillaries. SPECT imaging is distinct from the anterior and posterior 2D images obtained for lymphoscintigraphy. Through a computer algorithm, the information collected as the gamma camera traverses its 360? path during SPECT imaging allows visualization of the imaging target from any point of view. None-the-less, most images are viewed in the three cardinal planes; transverse, coronal, and sagittal.
It is critical to bear in mind that like lymphoscintigraphic images, SPECT images are created when a gamma camera registers the radioactivity emitted by an injected tracer. Only tracer-associated radioactivity can be visualized. This may silhouette a bodily structure as is seen in the limbs of patients with severe lymphatic incompetence, but otherwise no anatomical information is collected during SPECT imaging. For example, in the case of lymph nodes, SPECT images will show a cluster of ovoid shapes. The viewer is left to infer the locations of these shapes since, in the absence of radiolabeled markers, the scan does not reveal their anatomic locations. The benefit of SPECT and other gamma camera-based imaging techniques is that they allow the viewer to make physiological inferences regarding the functional status of bodily structures and systems. The rationale for performing a SPECT scan is, therefore, to ask a question about physiology rather than anatomy.
How does SPECT/CT differ from SPECT?
SPECT/CT scanning developed from a desire to have the best of both worlds – precise anatomic and physiological information. During SPECT/CT scanning, a CT (computed tomography) scan is acquired simultaneously with a SPECT scan. The SPECT and CT images are subsequently fused to reveal the anatomic structures that correspond to the concentrated pools of radiolabeled tracer detected by the gamma camera. These pools may occur in lymph nodes, the liver, or endocrine glands, among many other structures depending on the injected tracer molecule. Figure 1 reveals a SPECT/CT scan acquired after technetium labeled sulfur colloid was injected into the interdigital web spaces and inner elbow of a patient undergoing treatment for breast cancer. The four bright spots on the image correspond to the lymph nodes that drain her arm. If one was to look only at the CT portion of this image, it would be impossible to distinguish which of the many small axillary lymph nodes (LNs) drained her arm. The SPECT image not only identifies which LNs drain her arm, but also reveals the location of LNs that may be too small to resolve with CT. SPECT/CT scanning can be applied to any clinical situation where both physiological and anatomic information is needed.
Why is SPECT/CT scanning relevant to lymphedema?
Because SPECT/CT scanning allows the viewer to localize all the lymph nodes that drain a specific bodily structure such as an arm or an organ, it may permit targeting or sparing of critical lymphatics during cancer treatments. Surgeons have utilized the information gained from SPECT/CT scanning to identify the lymph nodes at highest risk for harboring metastases. In these cases, radiolabeled tracer injected in the tumor bed migrates to regional lymph nodes where it can be detected using a Geiger counter, as with sentinel lymph node biopsies (SLNB), or a gamma camera. For breast SLNB, SPECT/CT scanning is rarely needed since the sentinel nodes are almost always found in the axilla. However, other tumor types involving the head and neck or genitalia may display highly variable drainage patterns.1 For this reason the information provided by a pre-operative SPECT/CT can help surgeons to target their dissections and thus avoid needless anatomic disruption.
Recently, our group demonstrated the feasibility of fusing SPECT/CT images with the CT scans utilized to plan radiation treatments for primary breast cancer.2 This effort allowed us to estimate the incidental irradiation delivered to "arm-draining" lymph nodes by tangent beams, that is radiation directed at breast, not lymphatic tissue. We found that 40% of "arm-draining" lymph nodes that had been surgically spared received potentially damaging doses of radiation.3 Over a third of the patients undergoing breast conservation therapy in our study received non-therapeutic, damaging radiation to their lymph nodes critical for arm drainage. Fortunately, the fusion of SPECT/CT and radiation planning CT images creates an opportunity to develop individualized radiation fields that minimize the exposure of these critical lymph nodes while ensuring the delivery of therapeutic doses to target tissues. Our group recently reported successfully blocking 57% of the lymph nodes critical for arm drainage using this technique among 27 patients.4
Can SPECT or SPECT/CT be of use to patients with established lymphedema?
SPECT/CT may allow localization of lymph flow abnormalities with potential therapeutic implications. For example, SPECT/CT images permit the identification of significant lymph vessel blockages and of alternate drainage routes, provided that sufficient tracer accumulates to permit their visualization. Alternatively large aberrant reflux tracts such as those depositing lymph from the legs into the genitalia could be localized and potentially sclerosed with real-time SPECT/CT guidance. SPECT/CT imaging reveals lymph nodes involved in collateral pathways established as the body attempts to restore lymphatic homeostasis following axillary dissection. Therefore, SPECT/CT may permit the targeting of these nodes for interventions, such as manual lymphatic drainage, designed to reinforce developing collaterals. A range of exciting possibilities have yet to be tapped as we begin to apply this benign and remarkably useful imaging technology to the field of Lymphology.
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