BONES METASTASES

BONES METASTASES Multiple bone lesions - more often Single metastases (myeloma, thyroid and kidney cancers) must be differentiated from primary bone tumors Osteolytic (lung, colon carcinomas, melanoma) Osteoblastic (multiple myeloma, breast and kidney carcinomas) – correspond to the reaction of the host bone to the metastases Mixed – characteristic for fast growing tumors (bone reaction cannot keep up with the tumor rate of growth)

CLINICAL MANIFESTATION Pain – the principal symptom Tends to be worse at night May be partially relieved by activity As the lesions progress becomes more constant Atelectasis Thromboembolic disease Loss of ambulatory ability

DIAGNOSIS Plain radiography Bone scintigraphy Remains the most specific test The fastest, least expensive, most readily available Greatly assists surgical planning Should be the first test in the evaluation of pain! Bone scintigraphy Extremely sensitive Shows disease much earlier than radiographs* Practical – screens the entire body at one time Any abnormality found on bone scan should be assessed with plain radiographs (does not evaluate the structural integrity of the skeleton) False-negative bone scans – multiple myeloma, lung cancer, melanoma** Can be used to evaluate the response to therapy *Nearly 30% of bone mineral must be lost for a lesion to appear on plain radiograph. **Grow rapidly and evoke little reactive bone formation

DIAGNOSIS CT Very effective in evaluating the 3-dimensional integrity of bone Very useful in evaluating tumors in the pelvic and shoulder girdles Demonstrates the bone mineral content and cortical integrity better than MRI MRI The best method to evaluate bone marrow, the first site of most metastatic cancers Especially suited to the spine Helpful in distinguishing pathologic fracture due to osteoporosis from that due to tumor

DIAGNOSIS Biopsy CT-guided needle biopsy - satisfactory when the lesion is osteolytic - may be especially helpful in determining cancer regrowth or necrosis in area that has been already irradiated Open surgical biopsy when the lesion is osteoblastic or there is a thick overlying cortical rim * Increased fracture risk Difficulty to insert a needle

TREATMENT - RADIOTHERAPY Should be considered in all but the few cases: - the disease is very responsive to systemic treatment (e.g. germ cell tumor, lymphoma) - the lesions are resectable for cure * More than 80% of patients with a limited number of well-localized bony metastases can be treated effectively by external beam radiation

TREATMENT - RADIOTHERAPY Relieves pain, at least, in 80-90% of patients* -> reduces the need for narcotic analgesics -> improves activity Arrests local tumor growth * localized external radiation * hemibody radiation – for widely disseminated bone disease *The speed of response is variable. When the cause of pain is neurologic, tumor regression can be prompt and relief rapid (e.g. spinal cord compression from lymphoma). 70% of patients experience some pain relief within 2 weeks of starting therapy. 90%-within 3 months. 55-65% of patients experience sustained pain relief for 1 year or more. If there is a sudden increse in pain after the start of treatment a pathologic fracture may have occurred. Marrow fibrosis can be the late complcation that precludes chemotherapy if necessary.

TREATMENT - SURGERY Tumor excision – should be considered for isolated solitary metastases in case of long projected survival (renal or thyroid cancers) Amputation * Internal fixation of pathologic fractures** External fixation*** Principal surgical adjuvant – radiotherapy *In case of: 1) unreconstructable extremity lesions; 2) complications of the tumor treatment ( fungating infected lesion); 3) intractable pain ** Necessary to immobilize the bone, decrease pain, accelerate healing and ambulation of the patient *** Internal fixation is the most effective. EF is suitable for: 1) patients with extensive localized disease that cannot be immobilized by internal means; 2) preterminal patients in whom analgesic modalities can control symptoms; 3) patients in whom temporary medical problems prevent surgery

TREATMENT – SYSTEMIC RADIONUCLIDES Very effective in treating symptomatic bone metastases Treats all involved sites rapidly and selectively (reduced toxicity) Relieves pain Heals the underlying bone lesions Sr-89 (low-energy β emission)– response rates 50-90% Rh-185 (β and γ emission) Causes bone marrow supression May be complemented by local external beam radiation for optimal palliation of symptoms The strategy is to use a carrier that seeks the tumor. It localizes in the mineral of bone. Degradation of the isotope administers local shortacting radiation to the adjacent tumor cells. Gamma emission permits imaging of blastic tumors.Beta emission confers therapeutic value.

TREATMENT - BISPHOSPHONATES Treat hypercalcemia Stop bone reabsorption Reduce pain New-generation bisphosphonates may prevent the development of bony metastases Do not have a cytotoxic effect Do not interfere with other commonly used chemotherapeutic agents The indipendent mechnism of action makes them an attractive adjunct to other modes of treatment.