Radiation and Second Cancers
Ok, today I am getting back to work. I hope that you all had a lovely holiday season with at least some time for extra sleep and watching movies. It was a big help that the past two Mondays have been holidays, so there was really time to relax.
This is an encouraging article about the low risk (estimated at 1%) of second cancers caused by radiation therapy. For breast cancer, it is clear that the benefit of radiation far outweighs this concern. Here it is
Cancers Caused by Cancer Treatment
Maddams et al.
Cancer survivors face a unique threat: the development of a second cancer caused by the intense therapies that saved their lives in the first place. The full extent of this risk is only slowly becoming apparent as numbers of aging cancer survivors are still low and treatment strategies have changed over the past few years.
Maddams and colleagues have tackled this problem by employing a new rapid method of estimating the cancer burden caused by radiotherapy in England. They used data from the regional Thames Cancer Registry to obtain hard numbers of
surviving radiotherapy--treated patients in South East England. These numbers were then extrapolated to cancer survivors in the entire country. The authors applied relative risks previously calculated for second cancers of individual primary sites by
the Surveillance Epidemiology and End Results (SEER) study performed in the United States and thereby estimated numbers of second cancers expected in UK cancer survivors in 2007. Using this strategy, they estimate that less than 1 percent
of new cancers registered in 2007 in the UK were associated with radiotherapy of previous cancers.
Radiotherapy--associated second cancers involved most frequently the lung, the esophagus and the breast and occurred in more than half of the cases in older people aged 75 or above. The authors caution that their method did not take into
account confounding factors such as smoking or specific pathological or clinical factors of the first cancer, but they are optimistic that it provides a reasonable estimate of risk of secondary cancers due to radiotherapy.