Cytogenetics / Radiation- induced
Malformation
By Sharmila Sanmuganithi

What is cytogenetics?
Cytogenetics is the study of chromosomes and its abnormalities.
Cytogenetic Techniques: Routine analysis of G- Banded chromosomes,
cytogenetic banding techniques, molecular cytogenetics such as fluorescent in
situ hybridization (FISH) and comparative genomic hybridization (CGH).

Radiation Techniques: 3- Dimensional Treatment Planning, External Beam
Radiation, IMRT ( Intensity Modulated Radiation Therapy), Stereotactic
Radiosurgery, Prostate Seed Implants, Brachytherapy, Concurrent Chemotherapy and Radiation Therapy.

Imaging Techniques: X-rays, CT scans, MRIs, fMRI, Tomography and PET.

General Facts: Although radiation treatment is painless, many patients
receive acute and long term side effects after the treatment. These effects
depend on the part of the body treated and the amount of tissue that
receives radiation.

Acute Side Effects:
Radiation Nausea- patients may experience nausea after treatment, but the degree of vomiting/nausea varies from person to person. It depends on the amount of radiation. Patients are encourage to maintain fluid intake.

Hair Loss (Alopecia)- Hair loss may occur throughout the body including head, pubic area, face arms, legs, and underarm. This may lead to one’s psychological and emotional abnormalities.

Weight loss- Reduction of calorie intake due to pain and sore in the GI tract.
Fatigue / Malaise- Tiredness and lack of energy can be felt.

Low Blood Count- Blood elements can be reduced due to radiation. This may be due to the radiation exposure of bone marrow, and it can damage lymphocytes and lymph nodes. Number of WBC and Platelets may also be reduced.

Skin – irritation, inflammation, and dysfunction of skin

Defects in Mucous Membranes- radiation exposure in mouth, pharynx, esophagus, trachea, bowel, bladder or rectum will lead to mucositis. Mucositis may develop after radiation treatment and it breaks down the rapidly divided epithelial cells lining GI tract. This leaves the tissue open for ulceration and infection. There may be discomfort, dysphagia, cough, hoarseness, tracheitis, dysuria, diarrhoea and abdominal cramps.

Defects in Accessory Glands- such as saliva and mucous producing glands, lead to oral discomfort, dryness and change taste, irritating cough, and urinary or bowl symptoms.

Dry Mouth and Throat- leads to eating difficulties.

Loss of taste- sore and pain in the GI tract.

Long-Term Effects:

Scarring and Fibrosis- radiation can increase fibrous connective tissue formation, and this may lead to increased rigidity of tissues, less suppleness, less resistance to injury and blood walls thickening. Reduction of blood supply due to blood wall thickening can cause major problems during other surgeries or trauma.

Carcinogenicity- development of cancer after few years can be a result of radiation exposure during the treatment. This occurs due to bone marrow damage during radiation therapy.

Genetic Effects- exposure of gonads to radiation increases the risk of physical mutation and genetic change. Failure conception due to damaged chromosomes during the radiation. This can induce the chances of having a abnormal child.

Slow healing process- the reduction of cells to reproduce

Infertility-radiation to the testicles can lead to permanent loss of sperm production, loss of erection, may not be able to have sex, inflammations of reproductive organs and so on.

Possible damages in brain, lungs, digestive tract and reproductive organ can occur.

Malformation of Embryo/fetus due to radiation exposure

Malformation and Prenatal Death – abnormal development and aborted pregnancies

Growth Retardation- Shorter, lighter babies with smaller head circumference than normal

Neurological Effects- Small Head Size (SHS), microcephaly

Severe Mental Retardation- (SMR) most sensitive period is 8-15 weeks post-conception

Intellectual deficit- Decline in IQ

Seizures- significant increase in seizures, mostly among those with SMR.

Occurrence of Malignancies- Childhood cancer

Reference:
Rosenbaum, Ernest. “Mucositis: Oral, Esophageal and Gastrointestinal Problems and Solutions.” October 28, 2005 <http://www.cancersupportive care.com/mucositis.html>.

HealthCastle.com. “Radiation Side Effects”.2007. <http://www.healthcastle.com/se_ radiation.shtml>

Young, John. “Possible Side Effects.” Surveillance, Epidemiology and End Results (SEER). September, 2000. <http://training.seer.cancer.gov/module_cancer_ treatment/unit2_radiation4_side_effects. html>

American Cancer Society .“Possible Side Effects of Radiation Therapy.”. January 23, 2007. <http://www.cancer.org/docroot/ETO/content/ETO_1_4X_Side_Effects_of_ Radiation_Therapy.asp?sitearea=ETO>

The Oral Cancer Foundation ”Side effects of radiation treatment” January, 2007. <http://www.oralcancerfoundation.org/facts/radiation_side_effects.htm>

Baxter, Sheila.  “Guidelines for the Medical Management of Pregnant Patients Exposed to Diagnostic Radiation” Madigan Army Medical Cente. January 03, 2007.
<http://www.mamc.amedd.army.mil/preventive_med/ hpo_pregnancy.htm