The incidence of cancer has risen alarmingly in the last few decades. About a hundred year ago, cancer was not so common, but now every fourth person is having lifetime risk of cancer. The most important step in our fight against cancer is early detection, which is possible only by creating awareness among the people and by conducting mass screening programmes. In India, carcinoma of the oral cavity, oropharynx, oesophagus, stomach, rectum, colon and the lung are common in men whereas carcinoma of the cervix and breast are common among women.
Cancer presents with a variety of generalised and localised symptoms. General symptoms of cancer include loss of appetite, loss of weight, fatigue, pain, malaise, drowsiness, fever, haemorrhage, anaemia and cachexia. Local symptoms vary in different cancers. There may be dysphagia in oesophageal cancer; cough in lung cancer; abdominal pain in ovarian cancer; bowel obstruction in colorectal cancer; haematuria in bladder cancer; headache in brain tumours; and paralysis in the spinal cord tumours. There are various other local symptoms depending on the site of cancer.
Different cancer institutes all over the world have listed certain warning signals, which indicate the possible onset of a cancer in the body. The seven most common warning signals of cancer that can be remembered by the mnemonic CAUTION are given below:
C .... Change in the bowel or the bladder habit.
A .... A sore that does not heal.
U .... Unusual bleeding or discharge.
T .... Thickening or lump in the breast or elsewhere.
I .... Indigestion or difficulty in swallowing.
O .... Obvious change in a wart or a mole.
N .... Nagging cough or hoarseness of voice.
Carcinoma of the breast can be detected by self-examination of the breast. All the women above 30 years of age are advised to learn self-examination of the breast. This examination becomes essential in nulliparous women and in the women having positive family history of breast cancer. Self-examination of the breast is recommended every month immediately after the menstrual period, when the breasts are soft. If a lump is found in the breast, the lady must consult an oncologist. Clinical examination of the breast is recommended every third year to all women below forty years of age and every year to all the women above forty years of age. Mammography is recommended every year to all the women above forty years of age to detect breast cancer at an early stage..
All the women above 35 years of age are advised to undergo Pap test every year to detect cancer of the cervix. Pap test was developed by George Pappainecolau of Cornell University in 1928 and has been extensively used since 1943. This is a simple test, in which microscopic examination of the cervical cells is conducted. Pap test has already saved the lives of thousands of women all over the world.
Endometrial tissue biopsy is recommended to all the high-risk women at the age of menopause to detect cancer of the uterus.
To detect cancer of the ovaries, annual pelvic examination is recommended to all women during the childbearing age to detect cancer of the ovary.
Cancer of the oral cavity is common among tobacco-chewers & smokers. Any non-healing ulcer on the tongue or in the mouth (especially in tobacco-chewers & smokers) should be suspected of cancer.
Endoscopic examination is recommended to those patients of peptic ulcer who develop haematemesis or start losing weight, to detect any sign of stomach cancer. Regular gastric washings should also be examined in all the suspected cases of stomach cancer to detect it at the earliest.
Digital rectal examination is recommended to all the persons above forty years of age to detect cancer of the rectum. It is to be repeated every year thereafter. Faecal examination for occult blood should be done in all the persons above fifty years of age to detect colorectal cancer. A person having complaints of unusual rectal bleeding and resistant diarrhoea or constipation should undergo digital rectal examination, sigmoidoscopy and barium enema to detect the colorectal cancer.
Prostate Specific Antigen (PSA) and Prostatic Acid Phosphatase (PAP) estimations are recommended to all the men above fifty years of age (to be repeated every year) to detect cancer of the prostate. Digital rectal examination is also helpful in detecting the prostatic cancer and is advised to all the men above fifty years of age.
Cystoscopy is recommended to all the patients having haematuria to detect any sign of urinary bladder cancer.
Haemogram and bone marrow cytology should be performed in all the suspected cases of leukaemia.
To detect a cancer in an early stage, regular medical check-ups including Biochemistry, X-rays, Ultrasound, Computed Tomography (CT scan) and Magnetic Resonance Imaging (MRI) are recommended to all the high-risk persons.
In the past, researchers observed that some cancers (malignant tumours) produce certain proteins such as Alpha Feto Protein (AFP) and Carcino-Embryonic Antigen (CEA), which are similar to those produced by the embryonic cells. These specific proteins were given the name of “Tumour Markers” because these were considered as telltale marks of the tumours. Later, it was observed that the cancerous cells also produce many other biochemicals including specific antigens, cytoplasmic proteins, enzymes and hormones. Tumour markers can now be defined as the biochemical indicators of cancer. These are used to confirm the diagnosis and to determine response of the therapy. Tumour markers also indicate relapse or recurrence of cancer. These can be used in mass cancer screening programmes. The tumour markers are estimated in the plasma and other body fluids.
Alpha Feto Protein (AFP) is normally produced by the foetal liver. The elevated plasma level of AFP in an adult indicates the presence of carcinoma of the liver. It is also raised in cancers of testis, stomach, pancreas, lung or the ovary.
Carcino-Embryonic Antigen (CEA) is another protein that is produced by cancerous cells of the large intestines, liver, stomach, pancreas, melanoma, lymphoma, cervix, bladder, kidney, thyroid and the ovary. CEA is also produced by some of the breast and the lung cancers.
Prostate Specific Antigen (PSA) and Prostatic Acid Phosphatase (PAP) are produced by cancerous cells of the prostate. These tumour markers can be used to detect the prostate cancer.
Immunoglobulins are tumour markers for multiple myeloma. Multiple myeloma patients were found to excrete an abnormal protein in their urine. This protein was first detected by Henry Bence-Jones at Guy’s hospital in London in 1847 and is named after him. Estimation of the Bence-Jones protein is still used in the diagnose multiple myeloma.
CA 125 is tumour marker for the ovarian cancer. It is also used to detect many other cancers including those of the uterus, cervix, lung, digestive tract, pancreas, liver, colon and the breast.
CA 19-9 is tumour marker for the colorectal and the pancreatic cancer. It is also used to detect carcinoma of the stomach and the bile duct.
CA 15-3 is tumour marker for the breast cancer. It is also used to detect cancers of the ovary, lung and the prostate.
CA 27-29 is tumour marker for the breast cancer. It is also used to detect cancers of the colon, stomach, kidney, ovary, lung, pancreas and the liver.
CA 72-4 is tumour marker for the stomach cancer.
Human Chorionic Gonadotrophin is tumour marker for trophoblastic tumours and non-seminomatous testicular tumours.
Neuron Specific Enolase is tumour marker for the small cell lung cancer and the neuroblastoma.
Pancreatic Oncofetal Antigen (POA) is a tumour marker for the pancreatic cancer.
Lactate Dehydrogenase (LDH) is an enzyme found in blood, which is normally produced by the RBCs, liver, brain and some other tissues of the body. Higher level of LDH indicates the possible presence of the non-Hodgkin’s lymphoma, Ewing’s sarcoma, leukaemia and the testicular cancer.
5-Hydoxy Indole Acetic Acid (5-HIAA) is tumour marker for carcinoid syndrome.
Catecholamines are tumour markers for pheochromocytoma.
Urinary Steroids are tumour markers for the adrenal carcinoma and the para neoplastic Cushing’s syndrome.
Calcitonin is tumour marker for the medullary cancer of thyroid, myeloma and the multiple endocrine neoplasia.
Thyroglobulins are tumour markers for recurrence of metastases of the thyroid cancer.
Antimalignin Antibody Screen (AMAS) is a less specific tumour marker that simply indicates the presence of a cancer in the body.
Pre-Cancerous Stage (Leukoplakia)
Pre-cancerous stage is a stage prior to cancer. Dysplasia of the cervix and Leukoplakia in the oral cavity are the common pre-cancerous stages. Leukoplakia is a white thickened patch that usually appears in the mucous membrane of the mouth, lips, tongue, vulva and anus. The oral cavity Leukoplakia is commonly seen in tobacco-chewers & smokers. With continued use of tobacco, it progresses to form cancer. On the other hand, if the person having Leukoplakia stops tobacco-chewing & smoking, the leukoplakic patch does not develop into cancer, instead it gradually reverts back to the normal tissue. Cervical dysplasia is an altered patch of cervical tissue that can progress to cancer. It can be detected by performing Pap test. An early detection of cervical dysplasia usually provides enough time to the patient for taking preventive measures. Studies conducted by the Imperial Cancer Research Fund in London on the women smokers having cervical dysplasia, revealed that the lesions reduce remarkably in those women who stop smoking for more than six months.
Difference Between Benign Tumours & Malignant Tumours
When a living cell in the body loses its control over the normal cell division due to some external or internal factors, it starts multiplying at a much faster rate, loosing all restraints and controls. This purposeless proliferation of cells usually forms a mass known as Tumour or Neoplasm, which may be benign or malignant in character. The benign tumour is usually encapsulated and grows in size at one site. It remains within the tissue of its origin and does not spread to other parts of the body. The benign tumour can be completely removed by surgery. On the other hand, malignant tumour invades adjoining tissues and also spreads to distant tissues and organs of the body through various routes including lymphatic and vascular channels. The concept of dividing tumours into benign and malignant groups is too rigid. It has been observed that there is a third group of the tumours, which can invade locally but do not metastasise. These tumours are called intermediate tumours, which include: adenoma of the bronchus, mixed salivary tumour, carcinoid tumour and basal cell carcinoma. Some of the benign tumours can become malignant. Some or all of the following changes may be observed when a benign tumour turns malignant: rapid growth of the tumour; increased vascularity of the tumour; fixation of the tumour; and metastasis of the tumour.