Sacral chordoma is a rare form of bone cancer that originates in the sacrum, the triangular bone located at the base of the spine. It accounts for approximately 1 in 800,000 individuals annually.
Understanding Sacral Chordoma
Sacral chordoma develops from remnants of the notochord, a rod-like structure present during embryonic development that forms the basic framework for the spine. While the notochord typically disappears before birth, small clusters of these cells can persist in adults, and rarely, these remnants can undergo changes leading to a chordoma.
About half of all chordomas are found in the sacrum, located between the hip bones. These tumors are characterized by their slow growth, often developing over years before symptoms become noticeable. Despite their slow growth, sacral chordomas are considered locally aggressive, meaning they can invade and damage surrounding tissues and structures. This local invasiveness, combined with the sacrum’s proximity to vital nerves and organs, makes these tumors challenging to treat effectively. Chordomas are more frequently diagnosed in men than women, typically between the ages of 40 and 60, with a median age of diagnosis around 58 years.
Recognizing Symptoms and Diagnosis
Symptoms of sacral chordoma can be subtle and non-specific in their early stages. Common indicators include localized pain in the lower back or buttocks, which may worsen when sitting. This pain can sometimes radiate into the legs, or individuals may experience numbness, tingling, or weakness in their legs due to nerve compression. Bladder or bowel dysfunction, such as difficulty with urination or constipation, can also occur as the tumor grows and affects nearby nerves.
The diagnostic process typically begins with a physical examination, where a doctor assesses the patient’s symptoms and neurological function. Imaging studies are then performed to visualize the tumor and determine its extent. Magnetic Resonance Imaging (MRI) is often the preferred imaging technique, as it provides detailed views of the tumor and its relationship to surrounding soft tissues. Computed Tomography (CT) scans are also commonly used, especially to evaluate bone involvement and to assess for any potential spread of the tumor to other areas of the body.
A definitive diagnosis of sacral chordoma requires a biopsy, where a small tissue sample is taken from the tumor and examined under a microscope by a pathologist. For sacral tumors, a CT-guided biopsy is often recommended to precisely guide the needle. This biopsy is important for differentiating sacral chordoma from other conditions that may present with similar symptoms.
Treatment and Management
The primary treatment for sacral chordoma is surgical resection, aiming for the complete removal of the tumor with clear margins. Achieving complete removal can be complex due to the tumor’s location near delicate nerves and structures within the sacrum. Despite the challenges, surgical removal offers the best chance for long-term local control. In cases where complete removal is not feasible due to the tumor’s size or involvement of critical structures, surgery may still be performed to remove as much of the tumor as possible.
Radiation therapy plays a significant role in the management of sacral chordoma, often used with surgery or as the primary treatment for tumors that cannot be surgically removed. High-precision techniques like proton beam therapy or carbon ion therapy are favored because they deliver radiation directly to the tumor while minimizing exposure to surrounding healthy tissues. Proton therapy, for instance, allows for escalated radiation doses to the tumor. Carbon ion radiotherapy has shown promising outcomes for unresectable sacral chordomas, with studies reporting favorable local control and survival rates. Conventional chemotherapy generally has a limited role in treating sacral chordoma, as these tumors are not very sensitive to it.
Long-term follow-up and monitoring are important to detect any signs of recurrence. Recurrence is a common concern even after initial treatment. Regular imaging scans are part of post-treatment care.