Ep 141: A 51-Year-Old with Stage 3 Breast Cancer

A woman with a history of breast cancer presents with new back pain. This episode explores the differential diagnosis and diagnostic procedures.

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Transcript

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[Ms. Heidhausen] This is Katerina Heidhausen, executive editor of Harrison's Principles of Internal Medicine. Harrison's Podclass is brought to you by McGraw Hill's AccessMedicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, on to the episode. 

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[Dr. Handy] Hi, everyone. Welcome back to Harrison's Podclass. We're your co-hosts, I'm Dr. Cathy Handy. 

[Dr. Wiener] And I'm Dr. Charlie Wiener, and we're joining you from the Johns Hopkins School of Medicine. 

[Dr. Handy] Welcome to episode 141: a 51-year-old with stage 3 breast cancer. 

[Dr. Wiener] Cathy, today's patient is a 51-year-old woman who four years ago was diagnosed with stage 3 breast cancer. She was treated with surgery and adjuvant chemotherapy with an excellent response. Her past medical history is notable for chronic low back pain that developed in her 30s related to her work as an airport baggage handler. She takes non-steroidal anti-inflammatories daily and occasional narcotics as needed. She comes to you reporting that she's noticed new pain in her mid-back for the past week that has not responded to those therapies and she's asking for additional treatment. She really has no other medical issues. Her only other medication is tamoxifen. 

[Dr. Handy] Tell me more about her medical history first. What does she mean by new pain? Was there any inciting event? And tell me more about the pain too. Is it positional, pleuritic? How does this relate to her chronic pain? 

[Dr. Wiener] Good questions. So her typical pain is in her lumbosacral areas, and it's both dull and sharp, worse in the morning when she gets out of bed, and then it typically subsides with movement or going to work. This new pain, which started about a week ago, is higher up, about around where her bra strap crosses. It's sharper, it's worse at the midline, and it actually gets worse at night while she's lying in bed or when she coughs. It is released somewhat by taking her prescribed narcotics, but it's not improved even with taking a few days off work. 

[Dr. Handy] So this sounds like it's different than her usual pain, so I would not want to ascribe this to her prior occupational injury. While low back pain is very common, mid-thoracic pain due to degenerative disease is not common. Can you tell me more about her physical examination? 

[Dr. Wiener] Sure. Her vital signs are normal and she's fully oriented and appropriate. Lungs, heart, abdomen are all normal. Her surgical site from her prior lumpectomy is well healed with no lesions. There's no axillary or cervical lymph adenopathy. She does have some point tenderness at her mid-thoracic spine around T6. There's no redness or vesicular lesions over the spine or laterally. The pain does not radiate. When taking deep breaths, she does report the pain is sharp and worse. There's no leg or arm weakness. And her reflexes and sensation are both normal in the upper and the lower extremities. 

[Dr. Handy] Okay, and I'm glad you mentioned the vesicular lesions because shingles is on the differential, but it sounds that's not the case 'cause after this long, shingles would typically have some vesicular lesions appearing. 

[Dr. Wiener] Okay, well what are you thinking then? 

[Dr. Handy] Well, one of the things I'm thinking about is spinal metastasis from her breast cancer. She did have stage 3 disease, so is at risk of recurrence, and a spinal metastasis would be a common presentation of recurrence. Breast cancer often goes to bone and the spine particularly. Also, this pain is very different from her chronic low back pain being in the thoracic area. If she were older and had a history of osteoporosis, I'd also worry about a degenerative compression fracture, but she doesn't seem at risk for that, so she does need further evaluation. 

[Dr. Wiener] Okay. Well, that gets us to our question which says, all of the following statements regarding spinal metastatic disease are true, except? So four true, one untrue. Option A. breast cancers are more likely to metastasize to the thoracic vertebra than the lumbosacral vertebra; option B. breast metastases to the spine are typically lytic, not blastic; option C. glucocorticoids can be administered before obtaining a radiologic study; option D. MRI with gadolinium can distinguish between metastatic disease and epidural abscess; and option E. plain radiographs have a greater than 90% sensitivity for identifying metastatic vertebral lesions. 

[Dr. Handy] Let's take a step back for a second and talk more about spinal cord disorders. As a clinician, your first step is to distinguish between compressive and non-compressive lesions. Since compressive causes require urgent treatment to avoid irreversible neurologic loss. 

[Dr. Wiener] Besides tumors, what are some other compressive lesions? 

[Dr. Handy] Well, you need to consider the other common causes such as epidural abscess or hematoma, a herniated disc, and spondylitic vertebral pathology. Non-compressive causes of acute myelopathy that are intrinsic to the cord include primarily vascular, inflammatory, and infectious etiologies. 

[Dr. Wiener] Is pain the typical presenting symptom? Our patient has no focal or neurologic defects. 

[Dr. Handy] So when talking about spinal metastases, pain is usually the initial symptom. And pain is rarely mild or absent. Patients characterize the pain as aching and localized, or sharp and radiating in quality. It typically worsens with movement, coughing, or sneezing, and characteristically awakens patients at night, as in our patient. A recent onset of persistent back pain, particularly if in the thoracic spine, which is uncommonly involved by spondylosis, should prompt consideration of vertebral metastases. 

[Dr. Wiener] You already mentioned breast, but which are the most common malignancies to involve spinal metastases? 

[Dr. Handy] Almost any malignant tumor can metastasize to the spinal column, but breast, lung, prostate, kidney, lymphoma, and myeloma are the most frequent. The propensity of solid tumors to metastasize to the vertebral column probably reflects the high proportion of bone marrow located in the axial skeleton. 

[Dr. Wiener] What about location? Our patient is having thoracic pain. 

[Dr. Handy] The thoracic spinal column is most commonly involved. Exceptions are metastases from prostate and ovarian cancer which occur disproportionately in the sacral and lumbar vertebrae, probably from spread through Batson plexus, a network of veins along the anterior epidural space. Retroperitoneal neoplasms, especially the lymphomas or sarcomas, enter the spinal canal laterally through the intervertebral foramina and produce radicular pain with signs of weakness that corresponds to the level of involved nerve roots. 

[Dr. Wiener] That answer is option A. It's true that breast cancer is typically metastasized to the thoracic vertebrae. Let's go through the other options. 

[Dr. Handy] Well, let's start with diagnosis. So option D. is true. MRI with gadolinium is the ideal test and should be performed as soon as possible, and urgently if the patient has any focal neurologic deficits. MRI provides excellent anatomic resolution of the extent of spinal tumors and is able to distinguish between malignant lesions and other masses such as epidural abscess, tuberculoma, or lipoma, or epidural hemorrhage, among others, that can present in a similar fashion. Vertebral metastases are usually hypointense relative to a normal bone marrow signal on T1-weighted MRI. Often, infections of the spinal column, such as osteomyelitis, is on your differential as well. They look different on MRI because, unlike metastatic tumors, they often cross the disc space to involve the adjacent vertebral body. 

[Dr. Wiener] Option B proposes that metastatic breast cancer lesions are lytic, not blastic. Is that true? 

[Dr. Handy] Yes, that relates to pathology or plain radiology. Breast metastases are typically lytic not blastic. When you see blasting lesions in the bone or spine, you should think more about prostate or myeloma, but that also gets us to the one incorrect statement. It's not true that plain radiographs have over a 90% sensitivity for spinal metastases. Plain radiographs of the spine and radionuclide bone scans have a limited role in diagnosis of spinal metastases because they do not identify 15 to 20% of metastatic vertebral lesions and also fail to detect paravertebral masses that reach the epidural space through the intervertebral foramina. 

[Dr. Wiener] Okay, so then the last option talks about glucocorticoids and the timing of administration. 

[Dr. Handy] Immediate treatment for spinal metastases includes glucocorticoids, typically dexamethasone, to reduce cord edema. They can be administered before an imaging study if there's any concern for cord compression. If there is cord compression, proper management will be individualized based on the radiosensitivity or chemosensitivity of the primary tumor, the extent of compression, and the presence of additional lesions, and stability of the spine. 

[Dr. Wiener] Great, so the teaching points of this case are that new focal spine pain, particularly in the thoracic region, should raise the concern of a compressive spinal cord of vertebral issue. MRI is the best diagnostic modality. In the event of a spinal metastatic lesion with clinical or radiologic concern for spinal cord compression, glucocorticoids should be administered without delay. 

[Dr. Handy] You can find this question and others like it in Harrison's Self-Review, and you can read more about this topic in the Harrison's chapter on diseases of the spinal cord. Visit the show notes for links to helpful resources, including related chapters and review questions from Harrison's, available exclusively on AccessMedicine. If you enjoyed this episode, please leave us a review, so we can reach more listeners just like you. Thanks so much for listening. 

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