Bone metastatic cancer is a secondary tumor arising from the metastasis of malignant tumor originating from an organ of the body to the bone through blood circulation or lymphatic system, which has the third highest clinical incidence after liver and lung and occurs mostly in middle-aged and elderly patients between 40 and 60 years old. Bone metastases mostly occur in the trunk bone, with the spine being the most common, followed by ribs, iliac bone, femur, humerus, etc.
I. Diagnosis
(I) Diagnostic basis
1.Symptoms
Nearly half of the patients with bone metastases can show symptoms clinically. The clinical manifestations are mainly local progressive bone pain, functional impairment, fracture, spinal cord and nerve root compression symptoms.
(1) Local pain and pressure pain are often the first symptoms. The pain may be mild or severe, and is worse at night. The pain is intermittent at the beginning and is not related to activity, then it becomes constant and intensifies, and cannot be relieved by rest or braking.
(2) Deep bone metastases are often not easy to find the masses at the early stage, and only pain and dysfunction are the main symptoms, so X-ray examination is essential in this case. In superficial bone metastases, pain and swelling often appear at the same time, and a lump with unclear boundary, hard texture and not being pushed can be found locally. If the mass is large, superficial venous anger and elevated skin temperature can be seen.
(3) In some patients, the first symptom is a pathological fracture with severe pain, deformity, and abnormal activity. Prior to this, there are no conscious symptoms or even pain, and the patient survives with the tumor for months or years.
(4) Loss of activity function is an important feature of bone metastasis cancer. Pathological fracture of lower limbs caused by bone metastasis cancer or paraplegia caused by spinal destruction can make patients lose their activity function.
(5) In the late stage of bone metastases, there may be systemic symptoms such as mental depression, poor appetite, emaciation, weakness, anemia and hypothermia.
(6) Bone metastases in the spine can often compress the spinal cord and produce neurological compression symptoms.
(7) Severe osteolytic lesions may lead to hypercalcemia. Malignant hypercalcemia may include abdominal pain, intractable vomiting, extreme weakness, severe dehydration, rapid onset of renal failure, and even death by coma.
2.Signs
(1) Local mass, limited pressure pain, tenderness and percussion pain. The pain is often located below the plane of the lesion and is not easily localized.
(2) Pathological fracture causes corresponding functional impairment.
(3) Compression of the spinal cord produces corresponding signs of nerve compression, such as limb weakness and complete paralysis.
3.Auxiliary examination
(1) X-ray examination of metastatic bone tumor is divided into osteolytic, osteogenic and less mixed, the former is the most frequent, forming worm-like and chisel-like bone defects with unclear boundaries and irregular margins without sclerosis. Osteolytic destruction can be one bone foci, one bone multiple foci and multiple bone multiple foci.
There are three types of osteolytic lesions.
1) worm-like, characterized by multiple, small and medium-sized lesions combined into one large lesion, which is common in breast cancer metastases.
2) diffuse infiltrative type, which is mostly seen as a metastatic manifestation of small round cells such as lymphosarcoma, neuroblastoma and Ewing tumor
3) large and expansive lesions, such as bone metastases from thyroid and adrenal tumors. Osteogenic lesions are less common, and the osteogenic destruction is patchy and sheet-like with increased density, which is to ivory-like, with disturbed, thickened and rough bone trabeculae, and the volume of affected bone may increase.
The lesions are smaller than osteolytic lesions, and there are three types.
1) round and scattered, with clear borders and uniform density.
2) mottled, irregularly shaped with varying degrees of sclerosis.
3) diffuse, with larger lesions. Mixed bone metastases have both osteogenic and osteolytic x-ray manifestations.
(2) Radionuclide bone scan (ECT) Bone imaging is more sensitive than x-ray examination, and can detect suspicious disease 3-6 months before the appearance of changes on x-ray plain film.
It can detect the suspicious lesion 3-6 months before the change of X-ray plain film. Since most bone metastases are multiple, radionuclide bone imaging can detect multiple metastatic bone lesions at the same time in one examination, so bone imaging has early diagnostic value for bone metastases, and at the same time, it can depict the size of lesions, guide surgery and plan the resection range; it is also important for designing treatment plan and prognosis evaluation. Bone treated with radiotherapy may show isotope hypotropic areas. At present, 99mTc bone scan has become a routine examination.
(3) CT and MRI CT is not used as much as other organs to diagnose bone tumors, and although it has been reported in the literature that it is useful for the differential diagnosis of malignant and benign tumors, MRI is more effective. It can also clearly show the size and scope of the lesion and the relationship with the surrounding tissues and organs.
(4) Pathological biopsy shows that most of the metastatic cancers are adenocarcinomas. A few well-differentiated metastatic cancers can show the histological characteristics of the primary cancer, such as follicular formation of thyroid cancer, renal clear cell carcinoma and hepatocellular carcinoma. Some other bone metastases are not easy to identify the primary cancer site based on pathological examination alone.
(5) Laboratory tests include the measurement of blood calcium, phosphorus, AKP and CEA, but none of them is specific for the diagnosis of bone metastases. Patients with bone metastasis cancer often have anemia, decreased hemoglobin, decreased red blood cells and increased sedimentation. Alkaline phosphatase is often elevated in cases of extensive bone destruction; acid phosphatase is elevated in the blood of those with prostate cancer bone metastases. Patients’ blood phosphorus is generally normal. High blood calcium is not directly associated with extensive bone metastases, although patients with bone metastases tend to have elevated blood calcium levels. Catecholamine measurement in urine is helpful in the diagnosis of neuroblastoma.
(II) Differential diagnosis
1.Bone metastasis and primary bone tumor
The former may have clinical manifestations of the primary tumor before the appearance of local pain and mass, while the latter has no history of other systemic tumors, and pathological biopsy can help to differentiate them.
2.Pathological fracture and normal fracture
A few bone metastases have pathological fracture as the first symptom, often without obvious cause, while the latter often has obvious history of local trauma (e.g. impact, fall). x-ray examination and whole body examination to find the primary tumor can help differentiate the two.
3.Differentiation with osteoporosis
C11 and X-ray of osteoporosis show intact cortex and small dense sparse area; while the cortex of bone metastases is incomplete and the size of destruction varies.
(iii) Common complications
Including severe osteolytic lesions can be to hypercalcemia, osteonecrosis and pathological fracture, spinal cord transection syndrome.
II. General treatment
1, light and nutritious diet for osteoporosis caused by bone destruction, can be taken orally active vitamin D drugs, such as Alfa D3, which can promote bone calcification, reduce bone calcium dissolution, release bone pain. In the diet can increase calcium food such as milk, fish and shrimp, soy products, etc., to prevent further osteoporosis.
2.Early stage asymptomatic people can combine labor and rest, but late stage especially those with multiple bone metastases should absolutely rest in bed.
When the pain is severe, effective pain medication should be given in strict accordance with the “three-step pain relief treatment principle”.
That is, oral administration, timely administration, stepwise administration and individualized dosage. The drug should never be given after the occurrence of pain, but should be given when the effect of the last drug has just disappeared, so that the pain is in a state of continuous relief.
4, to maintain emotional stability, the necessary psychotherapy according to the situation, respectively, to take implied therapy, supportive therapy, behavioral therapy and distraction, etc., the application of proper, its effect can be considerable.