In the next illustration, one will realize that early detection of cancer may not be beneficial if the cancers are non-progressive or grow very slowly. They are collectively referred to as pseudo disease (literally, "false disease"). These kinds of cancer don't exhibit symptoms, either because they don't grow at all or they grow so slowly that people die of other causes before symptoms appear.
The objective of screening is to detect and treat cancer at its early stage in order to increase survival rate. Based on the following illustration, one will notice that "longer survival" or "increased five-year survival" does not imply that death has been delayed, as it is equally likely that diagnosis simply occurred earlier in life.
One may argue that patients might be worse off, because they must live longer with the knowledge they have cancer and have to look out for the "time bomb" - having no peace of mind for the rest of their lives.
Cancer screening can be a tedious and long-drawn affair. Some women will find the following story familiar and quite similar to their experience of endless cycle of Pap smear screening for cervical cancer.
My friend went for her Pap smear screening and was told that it was abnormal. In medical term, it is ASCUS - "atypical squamous cells of unknown significance" which are frequently detected in a Pap smear. It's not cancer, but it's not normal - it is an "indeterminate" result.
The test was repeated every 3-6 months for three years. Finally, she was given laser therapy. One year after the laser therapy, her Pap smear was abnormal again. She was determined to fight it by taking some health supplements. In 2007, she was overjoyed when she passed her Pap smear test. Sadly, her joy was short-lived. In June 2008, she was diagnosed of Thymic Carcinoma (4th stage).
Recently, a friend shared with me that overseas cancer patients' survival rates are much higher than those of local cancer patients. She asked for my comments if it is true that our local treatment protocols are not as good as those available overseas. This is a tricky question and I reserve my comments. Perhaps, after reading this write-up, she will find the answer.
Some years ago, I read about a lawsuit filed against a local hospital by a patient for the wrong diagnosis of liver cancer. The patient received cancer treatment and found out the truth that he did not have cancer from his friend who is a doctor living overseas. The case was settled out of court for an undisclosed sum of compensation.
Patients might like to know the role of pathologists and radiologists in cancer diagnosis. They have the final say on the question of who has and who does not have cancer. The below illustration is adapted from a survey conducted overseas
From a casual conversation with a hospital staff, more people are joining the queue for screening of cancers owing to the success of cancer screening campaigns carried out by some local hospitals and cancer charities. As a result, the queue for cancer screening at public hospitals gets longer and resources are overstretched. In one public medical institution, their Radiation Department personnel are required to work longer hours in order to cope with the increased workload.
Survey studies in the United States show that radiologists reported more symptoms of blurred vision, eyestrain, difficulty in focusing, and headache arising from work overload. The huge amount of imaging data generated has the high potential for fatigue, discontent, and possibly increased error rates.
If one has a particular interest in avoiding death from cancer, cancer screening may be the dominant cancer prevention strategy to look for cancer in people who have no symptoms. Please bear in mind that cancer screening is not foolproof.
Given the above spectrum of choices, I choose to minimize medical contact while I feel well. I appreciate the thoughtfulness of a friend who has been constantly urging me to go for screening for my gastric problem. Being skeptical about such screening, I will only go for it when the symptoms become prevalent.
Most importantly, we must understand the cause of illnesses so that we can take preventive measures to tackle them holistically. I reckon early detection of cancer from screening is not the same as prevention of cancer. Detection merely precedes treatment.
Posted on 5 July 2008