WHY RADIATION AFFECTS CANCER CELLS MORE THAN NORMAL CELLS – GREATER PROPORTION OF DIVIDING CELLS (PART 2)

It is important to realise how long the delay between treatment and cell death can be. Very rapidly growing tumours may start to shrink within a week or so of starting treatment because their cells divide every few days. On the other hand, the cells of slowly growing tumours only divide every few months. This means that a slowly growing tumour can keep shrinking for some months after radiation is finished.

A delay before radiation damage becomes obvious also occurs with normal cells. For example, the cells lining the mouth divide every day or so, cells on the skin surface every week or so. When radiation is stopped, a reaction in the mouth will quickly start getting better but a skin reaction can keep getting worse for a week or more. The longest delay is seen in the case of tissues whose cells very rarely divide other than when the tissue is injured. These tissues may look fairly normal and function fairly normally for years, but heal very slowly or not at all if they are injured or infected. This poor healing is only partly due to the fact that some of the cells die when they try to divide. Another reason is that blood and lymph vessels are also damaged by radiation leaving tissues with a poor blood supply and sluggish drainage.

Radiation damage to the reproductive ability of cells has one other possible serious consequence. This one is only of concern to those of you who are lucky enough to be cured, or at least to live many years after your treatment. People who have had radiation treatment have a higher than normal, but still small, risk of developing a completely new cancer within the irradiated areas. I am not referring here to a recurrence of the original cancer but to a completely new cancer caused by the radiation. Radiation-caused leukaemia typically develops about five years after radiation. Other types of cancer take twenty or more years. The risk is small but definite. When weighing up your cost/benefit balance, do try to keep this one in perspective. I stress that it will only concern you if your treatment is successful in controlling your original cancer.

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BREAST CANCER: POST-OPERATIVE COMPLICATIONS

As with any type of surgery, there can be general complications following breast cancer operations, such as chest infection and deep vein thrombosis. Although minor complications are fairly common, serious ones are rare.

Poor posture can lead to back pain, and reduced mobility and strength in the shoulder are sometimes caused by the adhesion of muscle fibres following breast operations. Nerve damage during surgery can also lead to problems such as difficulty in reaching forward with the arm. Good physiotherapy advice and regular exercises can help prevent or alleviate these complications.

Chest infection

Chest infection can occur following general anesthesia for any type of operation, and particularly when a painful wound makes deep breathing more difficult. It is especially common in smokers. Deep breathing is important after your operation to keep the lungs well aerated, and if you find it difficult, a physiotherapist may be able to visit you on the ward to advise you about breathing exercises.

Pneumothorax

Very rarely, when the breast and underlying muscles are removed, as in a radical mastectomy, it is possible for the membrane between the ribs to be damaged, thus allowing air to enter the thoracic cavity. This condition, known as pneumothorax, can cause partial or total collapse of the lungs, and an X-ray of the chest may be done following a radical mastectomy to make sure such damage has not occurred.

If you cough up blood and have a pain in your chest following a radical mastectomy, you should report this to your doctor so that the possibility of a pneumothorax can be investigated.

Deep vein thrombosis

This is quite a common complication following pelvic surgery, but less so after other types of operations. Precautions such as wearing anti-embolism stockings while immobile and having a course of heparin injections are usually taken to help prevent it occurring. If a blood clot (thrombus) forms in the deep veins of the body – most commonly in the calf veins of the legs – it can break away and the resulting embolus may pass through the heart and block the arteries of the lungs. The resulting pulmonary embolism can be life threatening. If a thrombus is detected, it can be treated with a course of heparin or warfarin.

Pain and bruising

Local anesthetic is often injected into the skin edges prior to closing the wound to help reduce the pain once you wake up. This pain-killing effect lasts for several hours, but when it wears off another form of pain relief will be required.

A sharp, intermittent pain in the chest wall is probably due to nerve regeneration or a trapped nerve; whereas an aching pain in the anterior chest can be caused by spasm of the pectoral is major muscle. Pain in the upper arm may be referred discomfort from the spine, possibly resulting from bad posture or, if the pain is in the back of the upper arm, it can also be due to nerve regeneration.

A stabbing pain may occur in the upper, outer part of the arm (sometimes not until a couple of weeks after surgery) which is likely to be associated with the return of sensation to the arm as post-operative numbness wears off.

Persistent pain which is not relieved by painkillers such as paracetamol, although unlikely to have a serious cause, is worth investigating, and you should seek medical advice if it occurs.

Even minor breast operations can cause severe bruising, which can be extensive and last for several days or weeks. Although the sight of such bruising may be distressing, there is unlikely to be any cause for concern.

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