Radiotherapy wait linked to cancer recurrence

The longer a woman is left waiting for radiotherapy after breast cancer surgery, the more chance there is that the disease will recur, the results of a new study indicate.

Four to six weeks is generally accepted as a reasonable interval between cancer surgery and radiotherapy, however until now, the evidence relating to waiting times in patients with breast cancer has been mixed.

Researchers from the US, Canada and Japan set out to examine the link between waiting for radiotherapy and breast cancer recurrence.

They analysed cancer records for over 18,000 women who had been diagnosed with early stage breast cancer between 1991 and 2002 when they were aged 65 or older. All of the participants had received cancer-related surgery and radiotherapy, but not chemotherapy. They were followed up for an average of five years.

The study found that women who started radiotherapy more than six weeks after surgery were at an increased risk of having the disease return. Some 30% of the participants started radiotherapy after six weeks and 734 (4%) experienced a local recurrence of the disease at five years.

A further analysis meanwhile showed a continuous relation between time to radiotherapy and local recurrence. According to the researchers, this suggests that initiating radiation therapy as soon as possible after surgery could minimise the risk of recurrence.

“The implication of a continuous relationship between start of radiotherapy and local recurrence is that there is no ‘safe’ threshold in terms of waiting time and that radiotherapy should therefore be started as soon as possible,” they said.

They added that the cost of increasing capacity to ensure uniformly short waiting times could be substantial and would need to be weighed against the small absolute benefit in local recurrence.

“But given the known negative impact of local recurrence on overall survival and the large numbers of women treated with radiotherapy for breast cancer, it seems appropriate to consider whether this is a price we should be prepared to pay.”

Details of these findings are published in the British Medical Journal.

[Posted: Wed 03/03/2010]