Tropic of cancer
Lifestyle changes, increased longevity and higher detection rates have made cancer the fourth-largest killer disease in India, reports Sanchita Sharma.
Last month, Rekha Chadak saw a public service advertisement on television asking women not to ignore lumps and knots in their breasts. "I suddenly realised that's exactly what I had been doing — ignoring a persistent lump in my left breast for four years," says the 36-year-old schoolteacher. She was diagnosed with breast cancer in March and last week underwent surgery at the All India Institute of Medical Sciences (AIIMS), New Delhi, to get two cancerous lumps removed.
"My grandmother had died of breast cancer but I did not make the connection. I have always been very healthy and could not imagine having cancer," says Chadak. This denial, say experts, is why cancer is the fourth-largest killer disease in the country after heart ailments, respiratory infections such as tuberculosis and pneumonia, and diarrhoeal diseases, which is the leading cause of death in infants.
At AIIMS, where 50 per cent of cancer patients are from outside Delhi, only 20 per cent are diagnosed in the first and second stages of the disease. "Chances of complete cure in the first two stages is 80 per cent even for fast-progressive cancers such as lung cancer, but most people come to us at a later stage. Cure then is possible in only 20 per cent cases," says Dr GK Rath, head of the department of radiation oncology, Institute Rotary Cancer Hospital, AIIMS. "In Kerala, 40 per cent of the cases are diagnosed in the early stage, so the cure rate is higher," he adds.
The Institute Rotary Cancer Hospital will become the first centre in Asia to acquire Synergy — an image-guided radiotherapy system that offers greater accuracy in treating tumors in the trunk, such as those in the breast, abdomen, liver, pancreas, gall bladder and lungs.
Mapping the disease
For a country like India, which takes the lead when it comes to several types of cancer, the new technology is long overdue. According to The Atlas of Cancer in India, the country has the highest incidence of cancer of the gall bladder, mouth, and lower pharynx in the world. The atlas was compiled by the Indian Council of Medical Research (ICMR), which tracks patterns and incidence of cancers across the country under the National Cancer Registry Programme.
Its findings took even cancer specialists by surprise. It turned out that women in Delhi have the highest rate of gall bladder cancer in the world, with 10 out of one lakh suffering from it. Districts in central, south, and northeast India reported the world's highest rates of cancer caused by tobacco.
Men in Mizoram's Aizawl district topped the list of cancer of the lower pharynx (11 out of one lakh) and tongue (seven out of one lakh). They also had the country's highest rate of stomach cancer, which was also found frequently in men in Bangalore and Chennai.
In Pondicherry, mouth cancer was prevalent in nine out of one lakh men — the highest rate in the world. The survey also detected high rates of thyroid cancer in women in the coastal districts of Kerala, Karnataka and Goa. In other states such as Tamil Nadu and Andhra Pradesh, bacterial infection caused by a stomach bug, Helicobacter pylori, was the leading cause of stomach and gastrointestinal cancers.
"Compared to this, the northern states have low rates of digestive infections caused by H. pylori," says ICMR director general Dr NK Ganguly. The atlas, he adds, will help researchers identify the risk factors in specific locations.
The mysterious trigger Cancer occurs because of changes in genes responsible for cell growth and repair. This in turn transforms a normal cell into a tumour cell. The progress from a pre-cancerous lesion to malignant tumours is a multi-stage process. The trigger could be external or genetic.
Tobacco abuse, unhealthy lifestyle, pollution, pesticides, poor diet, obesity or genetic history — anything can cause cancer. In rural areas, frequent infections could set it off. There is no direct cause-and-effect equation and this poses the biggest hurdle in cancer prevention.
Until now, only tobacco has been established as the single largest preventable cause of cancer. It can cause cancer of the lungs, larynx, throat, oesophagus, mouth, oral cavity, pancreas, bladder, stomach, liver or kidneys. And it's no secret that secondhand smoking can also lead to lung cancer, which is also highly prevalent in men in Kolkata, Mumbai, and Delhi.
There is also strong evidence that alcohol causes cancer of the oesophagus, pharynx, larynx, liver and breast. In urban areas, of late breast cancer has become more prevalent than cancer of the cervix among women. "Urban women also marry late and have children at a later age, if at all, which allows estrogen to play havoc with their bodies," says Dr Sameer Kaul, senior cancer surgeon, Apollo Hospitals.
Age of infection
One-fifth of cancers worldwide are caused by chronic infections. Hepatitis B virus HBV can cause liver cancer; human papilloma virus affects the cervix; Helicobacter pylori targets the stomach; schistosomes goes for the bladder; liver fluke involves the bile duct; and human immunodeficiency virus HIV causes Kaposi's sarcoma (cancer of the tissue under the skin, in the lining of the mouth, nose, and throat or in other organs) and lymphomas (malignant cell infiltration of the lymphatic system).
The incidence of cancer also rises dramatically with age, most likely due to risk accumulation over the life along with cell repair mechanisms becoming less effective as a person grows old.
"The reason hospitals are reporting more cases of cancer is because longevity has increased dramatically in the past two decades and more people are getting diagnosed and treated for cancer," says Anil Thagwani, senior resident at the AIIMS department of oncology. "No one dies of old age, they always succumb to a disease that their ageing body cannot fight. Till two decades ago, the reason for death was diagnosed in just a fraction of the people dying," he adds.
It's not a silent killer Contrary to popular belief, 70 per cent of cancers have symptoms (see box), though pain occurs only in the advanced stages. Because symptoms tend to be subtle in the early stage, these are often mistaken for signs of other, less threatening diseases. Some symptoms are specific to certain types of cancer; for example, a person with prostate cancer has trouble urinating and acute leukemia manifests itself in flu-like symptoms.
Most cancer treatment is brief, and usually requires a combination surgery, six weeks of radiotherapy and chemotherapy for up to six months. Also, all patients in need of pain relief could be helped if current knowledge about pain control and palliative care were applied.
In the midst of all this, there is also a silver lining. Oncologists say 40 per cent of cancers can be prevented by abstaining from tobacco, eating healthy diet, leading an active life and preventing infections.