EXPLAINING OF SECONDARY BONE CANCER




EXPLAINING OF SECONDARY BONE CANCER

Introduction

Secondary bone cancer or metastatic bone cancer means cancer or it is cells that are spread to the bone from other part of body cancer
secondary bone cancer are more common than the primary bone cancer
secondary bone cancer are second causes of pathological bone fractures after osteoporosis


what are the common organs give secondary or metastatic bone cancer

any cancer in the body can spread to the bone but in adults most common organ are those that arise from the paired midline organs as
  • Prostate cancer
  • Breast cancer
  • Lung cancer
  • Kidney cancer
  • thyroid cancer
  • Multiple myeloma
In children there are two main cancers which can spread to the bone they are
  • Neuroblastoma
  • Wilm,s tumour or nephroblastom


Secondary bone cancer usually are multifocal but thyroid and kidney cancer tend to produce solitary or single lesions
Secondary bone cancer has three form either bone destruction like osteoclast bone cell called (lytic lesion) seen in breast ,lung multiple myeloma, kidney and thyroid cancers or  bone formation  like osteoblast bone cell called blastic or (sclerotic lesion )  seen in prostate and breast cancers or mixed form both types seen in breast and lung cancers
Methods of cancer spread to the bone and common site of bone affected
The cancer cells reach or spread to the bone from other cancer organ by the following way
  • Direct spread from nearby structures or organs
  • Lymphatic spread by the lymph vessels to the bone
  • Blood spread by blood vessels to the bone
  • Intraspinal seeding or spreading of the cancer cells
Common bone affected
  • Vertebral column common in thoracic and lumber spine
  • Pelvic bone
  • Ribs
  • Skull
  • Sternum
  • Proximal femur
  • Humerus
  •   Spread below the knee or below the elbow are rare and these distal metastasis are almost always due to lung carcinoma
These bone are common site of metastasis because the red bone marrow in these bones are rich in capillary network and slow blood flow and has nutrient environment

This predilections to certain bone due to the cytokines , local growth factor that attract and support growth of these lesions in specific areas
Symptoms and signs of secondary bone cancer
  • Bone pain characterized by boring constant  continuous various from dull acking pain to severe pain more worse or increased at night not relieved by rest not related to daily activity not respond to usual anti-inflammatory drugs or simple analgesic
  •  Fracture or breakdown the bone affected by this secondaries which called pathological fractures
  • Symptoms due to increased serum calcium in the blood due to hyperclcaemia which arise  due to the bone secondaries include these symptoms nausea vomiting  increased ability for stone formation like kidney stones constipation and brain confusion and drowsiness lethargy and even coma
  • Neurological manifestations like back pain and lower limb weakness numbness para paresis or even paraplegia or paralysis or incontinence this is due to cancer cells invasion to spinal cord or nerves of spinal cord in the spinal canal causing compression on the cord or its nerves
  • Manifestations due to bone marrow invasion by cancer cells lead to decreased red blood cells count and produce anaemia in the form of pallor weakness and generalized fatigue and decreased white blood cells and produced leucopnia  in the form of low body resistance to infection as increase susceptibility to lobar pneumonia and also decreased platelets count and produced thrompocytopenia in the form of  increased bleeding tendency eg bleeding from nose (epistaxsis) or bleeding from gums and bruising or skin rashes as subcutaneous haematoma and the patient become more immune-compromised or has low immunity
Investigations of secondary bone cancer
The aims are to confirm diagnosis to known the source of primary cancer which give these secondaries and to identifies other secondary bone cancer or other deposits and to treat or to exclude the complications
Imaging study
Plain X rays radiography
Simple easy and good for diagnosis the secondary bone cancer appear on the X rays as 
Lytic lesion (bone destruction) or sclerotic or blastic lesion (new bone formation) but normal X rays do not exclude metastasis
Lytic lesion seen in breast lung and thyroid cancers typically and it is due to the cancer cells secreted factors that stimulate osteoclastic bone resorption or destruction  lytic lesion must be more than 1 cm and causes loss of more than 50% of bone matrix before they are visible on plain film
Sclerotic lesion seen in adenocarcinoma of the prostate that stimulated osteoblastic formation
Most secondary bone cancer produce a mixed lytic and sclerotic reaction
Isotope bone scanning
Rapid sensitive and good method for screening and evaluating the all skeleton for the presence of secondary bone cancer or multiple lesions
  by injection radiorsotopic material intravenous and it is rely on uptake of radioisotope by reactive bone not by the cancer and so do not  show purly lytic lesions eg myeloma or rapidly growing lesions where there is no sclerotic response
bone scanning may be give false positive result as in old fractures

Computerized tomography CT scanning

good soft tissue image soft tissue and bone secondaries or metastasis are clearly demonstrated 
To show lytic bone lesion and also showing reactive new bone formation
    
Magnetic resonance imaging MRI scanning

More sensitive than CT  scanning especially for lesions involved the spine
To show bone marrow infiltration

PET positron emission tomography

A recent imaging technique used to measure activity of cells in different parts of the body
 low dose of radioactive substance like glucose is injected intravenous it will presented that
the cancer cells are usually more active than surrounding tissue which appear on the scan
For more details see the articles of muscloskeletal or bone imaging
Laboratory investigations of secondary bone cancer


  • Full blood count (FBC) to detect anemia(RBC) leucopenia (WBC) thrombocytopenia ( platelets deficiency) in case of bone marrow invasion
  •  Liver function test may show raising alkaline phosphatase enzyme in case patient with multiple lesions
  • Electrolytes as serum calcium level may arise in some tumours producing hpypercalcemia as result of secretion of parathyroid hormones (PHP- like protein) or secondary to massive osteolysis by the tumour cells
  • C-reactive protein (CPR)  and erythrocyte sedimentation rate (ESR) may raised
How we can identify the source of primary tumour which gives the secondaries bone cancer
  • Breast examination in women
  • Soft tissue mammography for breast cancer detection if not find by examination
  • Prostatic examination in men by per-rectum or digital rectal examination(PR) to showing enlarged and any hard mass or nodule in the prostate
  • Prostatic ultrasound for detection of cancer prostate
  •  serum and urine electrophoresis for multiple myeloma
  • Tumour marker like prostatic specific antigen (PSA) as in prostatic carcinoma
  • CT scanning or abdominal ultrasound for detection of any gastrointestinal liver or kidney cancers
  • CT scanning and X rays chest for detection of lung cancer
  
Bone biopsy
Aim
For known the nature of the primary cancer if not known and for also diagnosis these secondaries are cancer or malignancy not other wise else
If the primary tumors don not detected by the previous investigations bone biopsy of the secondaries or lesions may give the required information about the nature of the primary cancer
True cut needle biopsy
which the needle pass through the skin to reach the bone secondary where a small piece of the bone are taken as a biopsy and send for histopathological examination
Incisional or Open biopsy
  
Which a small incision is done in the skin over the bone secondary or metastasis to reach the bone lesion where a small piece  is taken and send also for histopathological examination to reach the diagnosis
  
Treatment of secondary bone cancer

Aim
To control of the disease to relieve bone pain to maintain mobility and function of the bone to prevent future bone fractures to help nurse care to treatment the complications

Methods of treatment

Surgical treatment

  By remove or excision the affected lesion then strengthening the remaining part of the bone by internal fixation according to type of the bone affected as by pin and screw or plating or intramedullary nailing for more details see
  To prevent fracture or used as prophylaxis which is more better to done than a fixation after complications 
If more than or 50% of single cortex of a long bone has been destroyed by metastatic disease that better to do prophylactic surgical interference as by intramedullary nail stabilisation
For cord compression by doing spinal cord decompression and stabilisarion also given high dose of steroid drugs to relieve edema and inflammation
Reconstruction for lesions around a joint as total hip replacement for lesions in the femoral neck or acetabulum

Pain relieves treatment of secondary bone tumour
  •  Non steroid anti-inflammatory drugs should be take chance
  • Bisphosphonates by it is action which act by reducing the activity of osteoclasts cells of the bone which responsible for  destruction old bone so it is decrease or prevent these destruction also help reduce breakdown of the bone and strengthen the existing bone also may reduce the need for radiotherapy and used also to decrease and treated the high serum calcium in the blood for examples disodium pamidronate , sodium clodronate (Bonefos) ibandronic and zoledronic acids
but Bisphosphonates have some side effect like flu - like symptoms joint and muscle pain decrease zcalcium give vitamin D and calcium as supplementation level in the blood sore throat indigestion and very rare side effect are osteonecrosis of the jaw bone which is common in people with removal teeth it may also causes loss of teeth  or poor healing of the gums
  • In anxious patients can give mild sedation especially at night due to the presence of sleeping trouble
  • general measures to get the patient attention away from the pain like listen to music spending long time in warm both
Radiotherapy
  • To relieve  pain and swelling
  • Two type of radiotherapy either external or internal radiotherapy
  • For more details see the articles of  cancer management by radiotherapy
Chemotherapy
  • To decrease size of the secondaries or shrinking it
  • Relieved symptoms and quality of life of the patient
  • For more details see the articles of management of cancer by chemotherapy
  



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