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Post radiation osteosarcoma - post radiation sarcoma

Summary

Post-radiation osteosarcoma is a type of secondary osteosarcoma (OS). It is defined as an osteosarcoma that occurs in the tissues that were treated with radiation for some other disease process. The tumor occurs after a latency period of several years (average is 17 y) following the radiation treatment, and is a direct complication of the treatment.

The incidence of secondary post-radiation sarcoma is related to the incidence of the primary cancers and diseases that are treated with high dose radiation. Published data suggest that males and females were equally affected, with age range 10 to 84 years old years old, and an average age 45.6 years.
Symptoms can go unnoticed for a fairly long time, or be misinterpreted by the patient and the doctor, and then an acute onset of constant and progressive pain and/or swelling occurs.
Radiographs most often shown aggressive pattern, with a mineralized soft-tissue mass and cortical bone destruction within the radiation field, and/or changes such as sclerosis and osteopenia.
A radiation oncologist, medical oncologist, and an orthopedic tumor specialist should be consulted to plan treatment. Surgical options include wide resection with limb salvage, or wide resection with amputation.
Complete Information on this Tumor
Introduction and Definition: 

Post-radiation osteosarcoma is a type of secondary osteosarcoma (OS). It is defined as an osteosarcoma that occurs in the tissues that were treated with radiation for some other disease process. The tumor occurs after a latency period of several years (average is 17 y) following the radiation treatment, and is a direct complication of the treatment. It is an uncommon tumor with an overall incidence rate of less than 1% for cancer patients treated with radiation who survive five years. It affects a wide age group and the prognosis and response to treatment is comparable with primary osteosarcoma.

Incidence and Demographics: 
The incidence of secondary post-radiation sarcoma is related to the incidence of the primary cancers and diseases that are treated with high dose radiation, which include childhood and adult cancers such as lymphoma, rhabdomyosarcoma, Ewing sarcoma, prostate cancer, and breast cancer. Post-radiation osteosarcoma patients are affected later than patients with primary osteosarcoma because it takes years before the tissues treated with radiation undergo malignant change. Published data suggest that males and females were equally affected, with age range 10 to 84 years old years old, and an average age 45.6 years. The axial and appendicular skeleton were equally affected.
Symptoms and Presentation: 

Symptoms can go unnoticed for a fairly long time, or be misinterpreted by the patient and the doctor, and then an acute onset of constant and progressive pain and/or swelling occurs. The pain is worse at night and is usually not relieved with aspirin or nonsteroidal drugs. Other symptoms include a development of a mass and/or a pathologic fracture near to the irradiation area with tenderness and/or bleeding.

X-Ray Appearance and Advanced Imaging Findings: 
Radiographs most often shown aggressive pattern, with a mineralized soft-tissue mass and cortical bone destruction within the radiation field, and/or changes such as sclerosis and osteopenia. Pulmonary metastases can be detected by a CT scan of the chest whereas technetium bone scan can be used to detect bone metastases. A CT and MRI scan are also required to determine the stage and degree of the tumor.
Preferred Biopsy Technique for this Tumor: 
If there is strong evidence of the cancer and only a confirmatory biopsy is needed, then fine-needle aspiration and/or trucut core biopsy may be performed to confirm diagnosis. If the diagnosis is not strongly suspected or the differential is broad, or tissue is needed to gather further information about the lesion such as type and grade, fine needle aspiration is frequently inadequate. A CT-guided core needle biopsy is a preferable option for a suspected lesion that is located deep inside the body and cannot be seen or felt by the physician. Open biopsy is sometimes preferable, and may sometimes be combined with an orthopedic procedure to stabilize the bone. Note that a biopsy may lead to complications if done incorrectly such as altering the appearance of an MRI; therefore, it should be done as the final diagnostic procedure. Biopsy performed prior to referral is associated with a higher rate of serious complications.
Histopathology findings: 
Upon microscopic examination, these tumors show the following characteristics: osteoid production; mitotic activity; variable necrosis; marked nuclear pleomorphism; pleomorphic plump high-grade spindle cells with neoplastic osteoid areas that appear pink in between the tumor cells. Gross findings indicate that these tumors are soft and fleshy; expansion to nearby soft tissue and formation of a soft tissue mass. There is also a possibility of seeing hemorrhage and necrosis.
Treatment Options for this Tumor: 
A radiation oncologist, medical oncologist, and an orthopedic tumor specialist should be consulted to plan treatment. Prior to surgery, there should be a thorough examination through imaging tests to determine if the tumor has become metastatic. Surgical options include wide resection with limb salvage, or wide resection with amputation. The choice is made by considering all of the factors such as the stage and location of the tumor in addition to the age and overall well being of the patient. The surgeon removes the tumor and if necessary, a prosthetic and/or allograft to reconstruct the missing bone segment is inserted. Radiation therapy may be used, ironically, prior or/and after the surgery. For the first two years after the surgery, a physical examination, laboratory tests, and imaging tests should be done and after the two years and up to the five years, assessments will be made by the physician.
Preferred Margin for this Tumor: 
Wide or radical required
Outcomes of Treatment and Prognosis: 
Published reports show a median survival of 33 months and a five year overall survival of 38%. The five-year disease-free survival rate was 17%. Note that the degree, stage, and location of the tumor greatly affect the treatment and prognosis of secondary osteosarcoma induced by radiation. For instance, localized, non-metastic tumors in the shoulder, hip, or knee has a better prognosis than a large tumor in the spine and pelvis because of its size and difficult location for complete surgical removal. In addition, a low-grade tumor has a higher rate of survival than a high-grade tumor and chance for survival is significantly lower in patients with metastasis. Surgical removal with chemotherapy may help the survival of patients with metastasis.
Special and Unusual Features: 
Extra measures should be taken to verify whether a patient indeed has radiation sarcoma because post-radiation changes such as fracture and other complications may present similar symptoms. Careful biopsy with several tissue samples may be necessary to confirm the postradiation osteosarcoma. As a result biopsy techniques that result in limited amounts of tissue for examination, such as fine needle aspiration and core needle biopsy, should be used with great care.