Errors in radiation treatment of cancer

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Errors in radiation treatment of cancer
Several hospitals do not participate in the virtually free audit programme
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A well trained clinician can detect exposures involving a 10 per cent or more over-dosage
If the dose delivered is less than 5 per cent of the prescribed amount many cancer cells survive
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Everyone knows that Bhabha Atomic Research Centre (BARC) contributes to the strategic areas in the country. Unknown to many, BARC has been, since 1976, rendering a priceless service to radiation therapy centres in India. It ensured that the error in the radiation dose to millions of cancer patients who undergo treatment remained within the clinically acceptable limits of plus or minus 5 per cent of the dose prescribed by radiation oncologists.
Side effects
Doses more than 5 per cent of the prescribed amount, lead to side effects; if less than 5 per cent, many cancer cells survive, causing recurrence. A well trained clinician can detect accidental exposures involving a 10 per cent or more over-dosage, based upon an unusually high incidence of adverse patient reactions (ICRP, 2000).
BARC started a postal dose quality audit programme in 1976, with 9 hospitals, using cobalt-60 machines, participating.
Presently, the Radiation Standards Section (RSS), BARC sends capsules containing a specially prepared thermo-luminescent powder to the hospital. As per instruction, the medical physicist of the hospital exposes them to a specific dose under specified conditions before returning them to BARC. BARC scientists at Trombay estimate the dose accurately.
Most hospitals deliver accurate radiation doses to patients. Some hospitals default. Atomic Energy Regulatory Board (AERB)/BARC has asked hospitals showing unacceptable errors to stop treatment of patients till the issue is resolved.
The service covered over 250 hospitals in India. From the 1990s, 80 per cent of the participants show deviations within acceptable limits compared to 50 to 60 per cent during the earlier period.
Many years ago, in one hospital, the source in its cobalt unit did not move into the treatment position; the patients did not receive any dose for a month, till BARC scientists identified the defect.
Another instance
In another instance, the dose was down by 40 per cent, as an engineer who repaired the unit shortened the length of a cable pulling the source into position. The audit service identified the latter.
During 2007-2008, (48th and 49th batch audit) eight beams showed errors of serious magnitude, ranging from -13.2 per cent to 72.8 per cent. They were due to calculation errors or mistaken irradiation of capsules. A positive deviation leads to under-dosing and inadequate treatment.
We may not know of adverse effects, if any, on any patient, as no one reported them to AERB, though the Atomic Energy (Radiation Protection) Rules, 2004 demand it.
It is appalling to note that several hospitals do not participate in this virtually free service which provides an independent verification of the dose. During February 2006, BARC invited 100 hospitals to the audit programme. Only 33 joined. The number joined and the number of invitations sent for a few batches are as follows: March 2007 (63/142); September 2008(37/98); May 2009 (65/207).
Analysis completed
The analysis for May 2009 is being completed. The number of hospitals with deviations of more than 10 per cent for the other years were 1, 10 and 4. One may feel that the number showing greater deviations are very few.
Little comfort
That is of little comfort for the 40 to 50 patients who may receive improper or inadequate radiation treatment at the defaulting hospitals every day. If there is a -20 per cent deviation, all the patients will get overdosed. An alert oncologist may find something amiss.
The deviations in the institutions which do not cooperate are unknown.
The callous, inexcusable indifference shown by many hospitals in not participating in the audit is at the cost of the patients. Patients may suffer unexpected side effects or receive inadequate treatment due to correctable errors.
Patients getting treated with cobalt machines or accelerators, or their relatives, may ask the head of the radiation therapy department whether the hospital participates in the BARC dose audit programme.
A dilemma
The programme faces a dilemma. Being a routine service, BARC, a research and development agency, may find it difficult to continue the programme routinely.
The stakeholders such as AERB, BARC, Directorate General of Health Services, State Directorates of Medical Education and Health Services must hand over the responsibility of dose audit to an agency, accredited by AERB. BARC can monitor the functioning of this agency. Such an audit by independent agencies is essential to ensure that cancer patients are receiving the correct dose and to avoid gruesome consequences of over-exposures from radiotherapy equipment.
K.S. PARTHASARATHY
FORMER SECRETARY, AERB
( ksparth@yahoo.co.uk)
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