Brachytherapy

Brachytherapy is a radiological method for treating tumors and cancers. It is also referred to as internal radiation and endocurie therapy. It is a conventional technique of radiation which is specifically administered into the body to treat cancers and also reduce or shrink tumors. Brachytherapy is used in the treatment of cancers in the liver, rectum, eye, prostate, breast, cervical and other soft tissues. In some cases brachytherapy is done in combination with the other cancer treatment methods to obtain accurate results. The source of radiation during brachytherapy appears as seeds and ribbons. These radioactive implants are administered in the patient's body.

Brachytherapy procedure

Before a brachytherapy procedure, oncologists evaluate the patient through CT scans and X-rays. Patients are counseled about the procedure and side effects involved in brachytherapy. Since brachytherapy involves the administration of implants, patients are generally catheterized. There are two types of brachytherapy treatment methods. They are classified on the location of the implants and dosage of the implants administered in the body.

Intracavitary brachytherapy: In this procedure, the implants are placed in close proximity of the tumor or the cancer in the body. Intracavitary brachytherapy is a temporary mode of treatment which is again associated with the dosage. In some cases, low dose rate implants are given and the patient is advised to remain in the therapy room for some time. This period of stay may vary from few hours to few days. The patient is kept in an isolated section until the radioactive implants are removed. The other method is by administering high doses. In this case the patient is advised to stay back in the treatment room for a few minutes. The patient is allowed to move out of the room after the radioactive substances are completely removed from the body.

Interstitial brachytherapy: The implants are placed within the zone of cancer or the tumor. This method may be temporary or permanent depending upon the type of cancer or tumor and the stage of metastases. In case of a permanent implant, the radiation subsides gradually. Dosage of the radioactive implants is a very significant factor in brachytherapy as it is directly associated with the results and risk factors that may emerge. Appropriate dosage of the radioactive implant either through intracavitary or interstitial methods, will prevent the damage of healthy tissue that is close to the cancerous tissue. The accuracy of this procedure is mainly due to the positioning of the radioactive implants near the cancerous region. Brachytherapy has lesser side effects when compared to external beam radiation therapies.

Risk factors of Brachytherapy

Dosage and positioning of the implants are very important factors as failure in one of the techniques can lead to damage of the adjacent tissues. Patients generally express discomfort during the procedure and some patients experience swelling and tenderness in the respective area after the procedure. Precautions in appropriate catheterization during implants can avoid normal tissue damage.

Restenosis

Restenosis refers to the re-narrowing of the coronary artery after an Angioplasty procedure. It literally means reoccurrence of the stenosis (narrowing of the blood vessel). Restenosis occurs within 3-6 moths in 40-50% of people who have undergone an Angioplasty.

During the procedure of angioplasty a balloon is inserted into the blocked artery and inflated so as to allow the blood to flow normally to all portions of the heart. During this procedure the surrounding tissues undergo trauma and become susceptible for damage. Restenosis may set in during thrombosis or due to fresh tissue growth at the site of the surgery. Restenosis does not indicate progression of the heart disease but may be an indication that the body's immune system is responding to the injury caused during angioplasty.

Modern medicine has seen the use of stents to keep the artery open. Usage of stents has brought down restenosis considerably. Usage of drug-eluting stent allows slow seepage of medication that reduces proliferation of cells thus reducing re-clogging.

Restenosis causes and treatment

Restenosis is mainly caused due to a surgery that unblocks or widens a blood vessel. Treatment depends on the clinical condition:

• If the original surgery had no stent, then a repeat surgery is performed and a stent is fixed.
  
• In case restenosis occurs even after stent has been placed during the first surgery then a repeat angioplasty is done.
  
• Many a times a second stent may also be placed.
  
• Bypass surgery wherein the affected portion of the artery is replaced with another artery from the patient's thigh.
  
• Brachytherapy; wherein radiation is used to remove the scar tissues from inside the artery.

Bone Sarcoma

The word 'sarcoma' is derived from the Greek word for 'fleshy'. Sarcomas arise from Mesenchymal tissue which is the precursor to fibrous tissue, muscle, bone and fat. Bone sarcoma is malignant tumor or cancer of the bone. The difference between the terms sarcoma and carcinoma is that while sarcomas spread through blood, carcinomas through lymph fluid to the nearby lymph nodes.

Symptoms of bone sarcoma

• Pain in the bones.
  
• Pain may worsen in the nights.
  
• Swelling, redness and tenderness at the site of bone pain.
  
• Swelling of the leg or arm in longer bones such as above or below the knee or upper arm, shoulder etc.
  
• Bone fracture after a routine movement – like throwing a ball.
  
• As cancer weakens bones, broken bones tend to occur more easily.
  
• Fatigue, fever and weight loss and anemia are other signs.
  

Causes of bone sarcoma

The cause is unknown in most cases although bone sarcoma can develop from benign lesions in the bone and areas that previously received radiation. Therefore persons who received radiation therapy or chemotherapy can be at increased risk. A genetic syndrome called Li Fraumeni and retinoblastoma and a disease called Paget's Disease are also associated with sarcoma.

Types of bone sarcoma

1. Osteosarcoma that occurs in the bones around the knee and upper arm.
2. Chondrosarcoma that begins at the cartilage and ends of bones and lines of joints and in pelvis, upper leg and shoulder.
3. The Ewing sarcoma family of tumors that occurs in bone but may also be present in the connective tissues located in the pelvis, legs and arms.
4. Multiple Myeloma which is a cancer of plasma cells that originates in bones.

Bone sarcoma diagnosis

A doctor examines the patient physically after ascertaining family medical history. Then the physician may recommend the following diagnostic tests:

• X rays in various parts of the body to show location, size and shape of bone tumor.
  
• Bone scans
  
• CT scans which reveal cross sectional images to check if the tumor has spread.
  
• MRI scans
  
• PET scans that image the body's metabolic action to show if cancer has spread.
  
• Biopsy
  

Treating Bone Sarcoma

Surgery plays a primary role in the treatment of bone sarcoma. The goal of surgery is twofold. On the one hand it can remove the cancerous tumors and restore the physical function and appearance. On the other hand, a cuff of normal tissue is taken from around the tumor cells to minimize the risk of tumor recurring at the local resection site.

After surgery, the reconstructive or plastic surgery team performs the delicate task of replacing bone. Musculoskeletal oncologists and reconstructive plastic surgeons use donor bone, the patient's own bone from other sites and metal implants to reconstruct limbs and restore function.

Radiation therapy: This can be performed before or after surgery or even during surgery though the use of brachytherapy. Radiation therapy is used to treat tumors or when there is disease recurrence at the site of the original tumor or other localized site. This is especially used in treating chondrosarcomas more often than bone sarcomas.

Chemotherapy: Chemotherapy is given before surgery in order to shrink the tumor and allow for better resection. Surgery and radiation can only act on a small area tumor site. Chemotherapy kills any cancer cells floating undetected elsewhere in the body.

Follow-up depends upon the grade and type of bone sarcoma. In case of Osteosarcoma and Chondrosarcoma, follow-up includes physical exam, chest x-ray which should be performed every three months for at least two years initially and then after four months for a year and then every six months for two years and subsequently annually.