Two weeks ago I saw a patient who is known to be a carrier of hepatitis C virus (HCV). He was diagnosed in 2005 but for the last few years had not had regular surveillance of his liver. He had felt bloated for a few months and saw his doctor recently. Subsequent investigations showed he had bilobe liver cancer (hepatocellular carcinoma, HCC) in a cirrhotic liver. Curative surgical resection was not an option as he had lesions in both the right and left lobes of the liver. [The best scenario for any patient with HCC is the presence of a small (< 2cm in diameter) tumour confined to one lobe of the liver (i.e. stage I / II cancer).] Would the situation be different if he had had regular surveillance?

Researchers from Hiroshima Prefectural Hospital reported the results of a study evaluating the usefulness of regular check-ups by ultrasonography and contrast-enhanced imaging for early detection of HCC in patients infected with HCV (J Gastroenterol 2009, Oct 29; epub). From April 2001 to March 2007, 240 consecutive HCV patients with HCC were studied. These patients could be classified into 3 groups:- Group A patients had their HCC diagnosed by regular, imaging surveillance; Group B patients had their HCC detected during scheduled doctor visits for liver disease or other diseases such as diabetes and Group C patients had their HCC detected when they felt a need to visit a doctor. The study found that the prevalence of single tumour at the time of diagnosis was 66% in group A patients. Group B patients had a prevalence of 48% while it was only 24% in group C patients. The percentage of stage I and II patients were 83% for group A, 53% for group B and 24% for group C. The number of patients who underwent curative procedure (surgical resection / ablation) was 99/124 (80%) in group A, 42/79 (53%) in group B and 10/37 (27%) in group C.

At the present moment, we cannot, with one blood or x-ray test, predict the risk of developing HCC in anyone who is a carrier of the hepatitis B (HBV) or C virus. The only way we can help these carriers is to perform regular blood and x-ray screening at 6 monthly intervals. The surveillance / screening is to afford us a chance to detect the liver cancer at an earlier stage. It does not stop the development of the cancer. If the liver cancer can be detected at an earlier stage, the chance of having a curative treatment is much higher.     

To all HBV & HCV carriers and people with liver cirrhosis, please remember to go for regular screening. Please do not wait until you have symptoms. It could be a bit late by then.

Long-term exposure to low-dose ionising radiation has been linked to the development of solid cancers and leukaemia. Consequently, workers in the healthcare sector and in the nuclear industry who are at risk for repeated radiation exposure have to be monitored. They are limited to an effective radiation dose of 100 mSv every 5 years, with a maximum of 50 mSv allowed in any given year. With the increasing use of radiological scanning in the general population, patients are not monitored for their overall exposure to ionising radiation and there is little information on the subject.

Researchers from Emory University recently conducted a study on 655,613 enrollees, aged 18 – 64 years, from 5 healthcare markets: Arizona; Dallas; Orlando, Florida; South Florida and Wisconsin (N Engl J Med 2009; 361: 849 – 857). The amount of radiation exposure to each patient over the period January 1 2005 to December 31 2007 was noted. The mean cumulative effective dose of radiation exposure from imaging procedures was 2.4 +/- 6.0 mSv per person per year. Women underwent significantly more imaging procedures than men; 78.7 % of women undergoing at least one procedure during the 3 year period as compared to 57.9% of men. The proportion of enrollees undergoing at least one procedure during the 3 year period increased with age as well: 49.5% aged 18 – 34 years versus 85.9% aged 60 – 64 years. While most of the patients studied had low exposure (≤ 3 mSv per year, equivalent to the background level of radiation from natural sources in the United States), not an insignificant number of enrollees were exposed to higher radiation doses. Moderate annual effective doses (> 3 – 20 mSv) were incurred at an annual rate of 193.8 / 1000 enrollees, while 18.6 / 1000 enrollees and 1.9 / 1000 enrollees had high (> 20 – 50 mSv) and very high (> 50 mSv) exposure, respectively. The top 5 imaging procedures with the largest contributions to the cumulative effective radiation dose were myocardial perfusion scanning (22.1%), CT of the abdomen (18.3%), CT of the pelvis (12.2%), CT of the chest (7.5%) and diagnostic cardiac catheterization (4.6%). From this study, it was estimated that approximately 4 million non-elderly adult Americans would be receiving > 20 mSv per year from imaging procedures.

Part of the reason why Joe Public requests various imaging procedures during health checks is the perception that, if the various scans are normal, he is safe and free of cancer. He is only safe at that point in time. There is no guarantee that a small cancer is already lurking somewhere in the body. The scan could not demonstrate it because it was too small for the machine to ‘see’. Furthermore, there is no stopping a new cancer from developing 3 months after the scanning procedures. Imaging procedures should be ordered and used judiciously. While the doctor looking after the patient has a duty not to over-investigate, the patient must also refrain from pressurizing the doctor into doing a scan just because the patient saw a health report on TV about how powerful XYZ scan is in detecting cancer of the little toe!