Performance Status Indicative of Need for Bone Scan in Kidney Cancer
According to a recent article published in the Journal of Urology, a patient’s performance status (ability to perform daily activities without symptoms) should dictate whether or not they undergo a bone scan when diagnosed with kidney cancer.
The kidneys are a pair of bean-shaped organs located on each side of the spine. The kidneys filter the blood and eliminate waste in the urine through a complex system of filtration tubules. All of the blood in the body passes through the kidneys approximately 20 times an hour. Renal cell cancer (RCC) is an uncommon form of cancer that is most often characterized by the presence of cancer cells in the lining of the filtration tubules of the kidney. Metastatic RCC refers to cancer that has spread outside the kidney to several and/or distant sites in the body.
Upon diagnosis of kidney cancer, patients undergo a battery of tests to determine the cancer’s extent of spread, as this will dictate treatment options. Patients will undergo a biopsy (removal and examination of a piece of tissue), and some scans which can determine if or where in the body the cancer may have spread. One type of scan that determines whether the cancer has spread to the bone (bone metastasis) is called a bone scan. Patients with early RCC often do not undergo a routine bone scan unless they are suffering from symptoms such as bone pain, and patients with advanced RCC often undergo routine bone scans, particularly prior to surgery. Researchers have been evaluating ways to determine which patients are at a high risk for having bone metastases so that only select patients undergo a bone scan.
Researchers recently conducted a clinical study to determine which variables may be indicative of bone metastases in patients diagnosed with RCC. This study included a database of 1,357 patients who underwent treatment that included surgery for RCC at a single institution, and whose data was reviewed in an attempt to find associations between specific variables and the presence of bone metastases. Of these patients, 37% had metastases, and 14% had bone metastases. Of all of the patient variables assessed, such as the extent of the cancer, presence of metastases, enzyme levels and symptoms of the muscular and skeletal systems, only a patient’s performance status was indicative of bone metastases. Patients with a performance status of 0 according to the Eastern Cooperative Oncology Group (ECOG) performance status scale, which refers to patients that are completely ambulatory and no symptoms that inhibit daily activities, had only a 1.4% incidence of bone metastasis, regardless of all other variables. However, patients with greater than an ECOG performance status of 0 had significantly higher rates of bone metastases. Other variables, including the extent of the tumor, presence of metastases to other areas of the body, muscular or skeletal symptoms, and/or specific enzyme levels that may be indicative of cancer spread, did not demonstrate the same significance in predicting bone metastases in these patients.
The researchers concluded that ECOG performance status scores are highly predictive of bone metastases in patients diagnosed with RCC. Patients that have an ECOG performance status of greater than 0 are at a higher risk of having bone metastases and may benefit from a bone scan during their diagnostic work-up or prior to surgery. However, patients with an EGOC performance status of 0, particularly those without any bone pain or other metastases, are at a very low risk of having bone metastases. Patients diagnosed with RCC may wish to speak with their physician about their individual risks and benefits of undergoing a bone scan.
Reference: Shvarts O, Lam J, Hyung K, et al. Eastern Cooperative Oncology Group performance status predicts bone metastasis in patients presenting with renal cell carcinoma: implications for preoperative bone scans. Journal of Urology. 2004;172:867-870.
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