Metastatic Bone Disease

 

 

 The skeletal system is one of the commonest site of secondary metastasis of malignant disease. Patient over 50 years’ metastatic bone disease are more frequent than all malignant bone tumour together. Secondary bone tumour arises from primary source elsewhere in the body, though about 10% cases primary sites cannot be detected. Evaluating the characteristics of metastatic bone disease is significant for proper diagnosis and management system of this type of disease.

 

Common primary source-

 Breast, then prostate, kidney, lung, thyroid, Bladder and gastrointestinal tract.

Common site of metastasis-

Vertebrae, pelvic bone, ribs, Proximal half of femur and the humerus.

Pathogenecity: 

Metastatic lesions are commonly osteolytic and more chance of pathological fractute. Bone resorption due to direct action of tumour cells, OR due to tumour derived factors which stimulate osteoclastic activity. Osteoblastic lesions are less common.

 

 Bone metastases symptoms and signs-  

Common age of The patient is 50 years to 70 years. Pain is commonest- as  Backache, Thigh pain. Pathological fracture, vertebral collapse, some lesion may diagnose incidentally with silent clinical features. Symptoms of hypercalcemia include thirst, anorexia nausea polyuria, Abdominal pain general weakness,and depression.In children-bone pain,abdominal mass-(adrenal Neuroblatoma)

Imaging:  

X-ray-

Most skeletal deposits are osteolytic, appear like rarified area in medulla and produce mouth-eaten appearance in cortex. Bone destruction, Pathological fracture,

Osteoblastic deposits seen also-in prostatic carcinoma

Radio scintigraphy

 —99mTcMDP radio isotope scanning is most sensitive method of detecting silent metastatic deposits in bone, Areas of increased activity found.

Laboratory Investigation: 

ESR-increased, HB%-decreased .Serum Alkaline phosphatase may be increased, Acid phosphatase level also elevated. Tumour associated antigen or tumour marker can be identified .

Treatment: 

Solitary lesion can be deals with radical treatment combined chemotherapy,radiotherapy and surgery, Most of the cases with multiple secondaries, Treatment is entirely symptomatic.

Palliative Care-

Great measures should be taken as prognosis is very poor, patient deserved to to be made comfortable And Patient need sympathetic counseling also.

Control of pain and metastatic activity-

Analgesic, Narcotics (late stage), Radiotherapy- if not contraindicated, Radiotherapy controls pain and size of metastatic growth.Hormone therapy- stibosterole for prostatic cancer, androgenic drugs or oestrogen for carcinoma of breast. For disseminated Secondaries from carcinoma of breast sometime treated with oophorectomy combined with adrenalectomy or hypophyseal ablation.

 

Treatment of hypercalcemia-

Hypercalcemia may have serious consequence like renal acidosis, naphrocalcinosis, unconsciousness and coma. Adequate hydration, reduction of calcium intake, and if needed bisphosphonate can be used.

Treatment of limb fractures

Internal fixation and packing with methylmethacrylate cement  is used for pathological fracture due to metastasis,Surgical options are-intramedullary nailing,(shaft fracture) plate fixation for fracture near the joint or blade plate fixation or arthroplasty also can be done. Pelvic reconstruction, custom made prosthesis, If extensive surgery contraindicated- some times-excisionalarthroplasty can be done.

Benefits of internal fixation are- Relief of pain, Easy nursing care, and easy to get up the patient for other type of treatment without unnecessary discomfort.

Prophylactic fixation, when large deposits threaten to result in fracture.when 50% of single cortex has been destroyed, Avulsion fracture also. Mirels' scoring system accounts for indication of fixation. 8 or more score indicates a high risk, and need internal fixation specially before radiotherapy.

Score :     Site:                   Pain             Lesion           Size

   1           Upper limb         Mild,             Blastic            <1/3

   2           Lower limb         Moderate      Mixed            1/3-2/3

   3           Peritrochanteric   Functional    Lytic             > 2/3

 

Treatment of Metastatic Spinal Lesion

40 times more common than all primary spinal tumor together. 41-70 % of malignant tumour have spinal metastasis, Common site are Thoracic region and vertebral body.

Spinal Bracing- if fracture is stable,

If unstable-anterior or posterior Spinal Fixation

Preoperative CT or MRI required to identify cord compressing or threaten to cord compression, If so-decompression is carried out at the same time,

Some time debulking, or palliative surgery- Vertrebrectomy and Reconstruction.

Radiotherapy reserved alone for soft tissue compression and palliation for inoperable case.

Paliative surgery: 

 Surgery for debulking the tumour or removal of solitary lesion.

Sclerotic Bone Metastases

A type of metastatic bone disease characterized by formation of dense area in bone tissue, which is also known as osteoblastic or osteosclerotic secondary bone disease. Osteolastic activity increase as there is interaction between cancer cells and bone micro environment. This type of metastasis usually occur in prostatic cancer, sometime in breast cancer and other malignancy also.

May be asymptomatic  as it does not involve normal architecture of bone But bone pain ,pathological fracture may occur.

Area involved in this type of metastasis- are spine, ribs, pelvis and long bone also.

X-ray, CT,MRI, Radioisotope scanning are diagnostic tools for osteoblastic type metastasis.

Treatment involve- 

 Chemotherapy, Hormone therapy, or Immune therapy  may be used.

Radiation Therapy,

Bone-Targeted Therapies :-Bisphosphonate,Monoclonal Antibody,

Surgery-  when pathological fracture,

Side Effects of Radiation Therapy for Bone Metastases-

Common side effects of radiotherapy are fatigue, skin eruption, bone pain nausea vomiting, hair loss, difficulty in swallowing, soft tissue damage, risk of fracture, secondary cancer in applied area.

 Metastatic bone tumours exposes multiple challenges for the patients and healthcare providers regarding management. A comprehensive and multidisciplinary approach for diagnosis and treatment of bone metastasis should be carried out. Appropriate Diagnosis and management protocols are needed for improving outcomes and maintaining quality of life of the patients of secondary metastatic bone diseases.