All chemotherapy agents generally have early side effects that subside over a period of weeks to months after therapy is completed. Several groups of chemotherapy agents also have specific late effects developing over months to years after treatment is completed. They are agent and dose dependent. Some of the common effects are listed below.

Alkylating agents: Include a large number of drugs and are grouped together based on common side effects. All alkylating agents can cause infertility by decreasing the production of sperms and eggs.

They can also cause early menopause if fertility is preserved, so that the number of reproductive years are fewer.

They also alter normal cells and predispose to the development of late second cancers.

These cancers are usually acute leukaemia or lymphoma but any tumor can occur. It is necessary to monitor for bone marrow dysfunction, changes in blood counts, etc. to detect the development of blood cell abnormalities.

1. Cyclophosphamide and ifosfamide: They can decrease kidney function and impair absorption of essential nutrients such as potassium, bicarbonate and phosphorus, or excretion of toxic waste substances such as urea and creatinine (kidney failure). They can cause damage and scarring of the urinary bladder. This can result in an urge to urinate frequently and cause blood and clots in the urine. Rarely the bladder has to be removed and urine surgically diverted.
2. Mustargen, BCNU, CCNU, melphalan: They can cause decreased lung function and volume. Kidney damage may occur and needs to be evaluated at follow up.
3. Cisplatin and carboplatin: They can cause decreased kidney function. The kidney may be unable to absorb magnesium so body magnesium levels become low and need to be supplemented. Hearing can be affected, especially with cisplatin. Hearing aids may become necessary if hearing tests are abnormal. This should be done early especially in a young child who is just learning to talk or in a child having school problems because of hearing difficulties.
4. Procarbazine and dacarbazine: Can cause infertility or increase the chances of miscarriage and still birth. There is no evidence that babies will be born deformed in any way because a parent received chemotherapy. Liver damage can occur, especially in combination with other agents that damage the liver.
5. Thiotepa: Can cause sterility and predisposes patients to the development of second cancers.
6. Busulfan: Can cause decreased lung function or liver damage. Long term monitoring is required.
7. Actinomycin D: By itself this drug has few late side effects. If used in combination with radiation therapy, it can increase the local side effects of radiation and cause increased skin inflammation and rash that eventually subsides with time. In combination with radiation and other therapeutic agents, it can accentuate damage to organs such as the lungs, heart, gastrointestinal tract, liver and kidney.
8. Anthracyclines: Examples are daunomycin, doxorubicin, idarubicin and mitoxantrone. They affect heart muscle growth and function and can cause defective heart function or heart failure. The heart may thus be unable to cope with excess demand especially with aggressive exercise or the extra demands of pregnancy. Regular follow up of heart function by EKG and/or echocardiogram is important to detect and treat these complications on time. Some symptoms of heart problems are excessive tiredness, shortness of breath, chronic cough that wonít go away and palpitation (being aware of regular or uneven heartbeats even at rest). Anthracyclines can augment radiation therapy damage like actinomycin D can. When combined with other agents, damage to the liver, gastrointestinal tract, lungs and kidney is increased.
9. Bleomycin: Causes fibrosis in the lungs and results in shortness of breath, poor exercise capacity, etc. These effects are enhanced by radiation to the chest. Pulmonary functions should be serially tested for early detection and treatment.
10. L-asparaginase: Can cause permanent damage to the pancreas and cause decreased digestive enzymes and diabetes. The drug increases the chances of developing clots within blood vessels and can cause clotting in the arms and legs but also permanent damage to vital organs such as the brain due to clot formation and decreased blood supply.

Antimetabolites:

1. Cytosine arabinoside (Ara-C): Can affect the central nervous system and cause weakness, seizures and altered consciousness especially when instilled in the spinal fluid or given in high doses.
2. Methotrexate: When instilled into the nervous system or given repeatedly as a high dose intravenously, methotrexate can cause learning disabilities especially in the young child. Serial testing is necessary to plan adequate intervention especially in school. Methotrexate can also precipitate seizures or have other manifestations of brain damage. It can also cause permanent scarring of the liver and kidney damage. Bones are weaker, and have less calcium when methotrexate is used for prolonged periods. Rarely, bones may undergo degeneration, causing pain, fractures or joint problems. All these need to be carefully monitored during and after methotrexate based therapy.
3. 6 mercaptopurine: Negligible long term side effects.
4. VP16 (etoposide), VM26 (teniposide): These drugs in high doses or with prolonged therapy predispose to the development of altered bone marrow function causing anaemia, bleeding and infections. This can progress to become leukaemia.

Hormones:

Steroids: Steroid use for long periods can cause cataracts in the eyes that will need to be surgically removed. The adrenal gland that normally produces essential steroids may stop doing so with long term steroid use and may never recover. Since this hormone is essential at times of stress to the body (such as surgery), supplementation may become necessary. Steroids also can weaken bones, alter growth, and affect bones around the hip joint causing a painful condition called ëavascular hip necrosis that will need orthopaedic intervention. Continued steroid use can cause weight gain, high blood pressure and diabetes that need medical attention.

Stem cell transplantation: High dose chemotherapy and/or radiation therapy is usually necessary before infusing stem cells for transplantation. Hence, all the side effects described above such as infertility and second cancers are more common and severe in transplant patients.

If bone marrow or stem cells were infused from another person, they can cause graft versus host disease. This can affect different organs and needs continued medical attention. Muscle weakness, joint stiffness or skin rash and thickening may occur because of radiation or graft versus host disease.

Physical and occupational therapy and guidance in addition to medical treatment can help. This may require special services especially in school and should be requested as needed.

Various organ functions such as eyes, lung, liver, gut and kidneys need to be serially monitored after transplantation. The immune system does not function well for many months or even years after a bone marrow transplant, especially when there is graft versus host disease, and all infections should be promptly and adequately treated.

Cyclosporine: Can cause seizures, high blood pressure, increased body hair and anaemia especially with prolonged use. Kidneys may not function well. It decreases function of cells of the immune system called lymphocytes increases the chances of fungal and viral infections.

It may predispose to the development of lymphomas (tumours) because of this immune suppression. Additional side effects of therapy

The immune system and infection: Radiation and chemotherapy temporarily (for about 3-6 months) destroy the immune system and care should be taken to avoid contact with infectious situations. Following transplantation, the immune system takes longer to recover (6 months to 1 year) especially if graft versus host disease is present.

Preventive medicines may be necessary after cancer treatment is completed. Infections also need early diagnosis and aggressive treatment. Vaccines are not given during treatment and vaccination should be resumed after treatment is completed (usually after 6 months to 1 year) based on medical advice.

Psychosocial and adjustment problems: Survivors of cancer need a lot of support and empathy from family and friends and yet should be allowed gradually to return to a normal lifestyle. Concerns about appearance, growth, learning disabilities, dental problems, sexual dysfunction and infertility may result in emotional stress that should be handled with the right amount of support and understanding. Medications may be of benefit medical consultation should be sought on time. In addition, interaction with support groups can help to relate better to side effects and handicaps.

Second cancers: Though most cancers are not hereditary and never infectious, there are some genetic disorders known as cancer predisposition syndromes that are associated with repeated cancers in different locations within one individual and similarly affected members of the family.

Because of the risk of second cancers either for genetic reasons or due to radiation and chemotherapy, regular medical follow up is wise and any unusual symptoms such as easy bruising or bleeding, swelling or skin lesions should be immediately investigated.

Excess weight gain: The loss of appetite and nausea that occur during therapy of cancer go away and appetite returns to normal gradually after therapy is completed. This can result in excess food intake and may be combined with restricted physical activity. This can frequently result in excess weight gain and obesity. A dietician will be able to advise regarding a healthy diet suitable for age and activity.