Treatment outweigh the benefits of radiation therapy small increased risk for a second cancer

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The proportion of second cancers related radiotherapy treatment for the first cancer in adulthood is small (about 8%), comes to the conclusion that an article in the Lancet Oncology online is published first. The results, the first study, the risk of routine radiotherapy for several types of first cancer *, quantify suggest that are second cancers by other factors such as lifestyle and genetics.

With improvements in cancer survival, the determination of the long-term risks of treatments such as radiation therapy has become important. It is established that radiation therapy treatment is associated with a risk to fall ill, but until now, what proportion of second cancer could be related with radiation therapy for a second cancer was not known.

Amy Berrington de Gonzalez of the National Cancer Institute, Rockville, MD, United States and gentlemen in this study collected data on 647 672 adult cancer survivors (, which survived for 5 years or longer) from the cancer register US surveillance, epidemiology and end results (SEER). You calculated the long-term risk of second cancers of radiotherapy treatment of the first solid cancer sites in these adults one follow up period of 30 years.

During the follow up (1978-2007), 9% (60 271) a second solid cancer developed the 5-year survivors.

The researchers estimated that these second cancers with radiotherapy treatment for the first cancer in connection could be 8% (about 3300). More than half of them were survivors in breast and prostate cancer.

The estimated proportion of second cancer associated with radiation therapy varies depending on the location of first cancer-by 4% for cancer of the eye and orbit by 24% for cancer of the testicles.

The risk of developing a second cancer was highest for patients exposed in a younger age and organs, higher doses of radiation, and increases with longer time from diagnosis.

For each 1000 patients treated with radiation therapy researchers estimated three excess radiation treatment types of cancer 10 years after a first diagnosis of cancer and five excess cancers of 15 years. These risks, say the authors, are too small in comparison probably use treatment.

The authors conclude: "these results can be used by doctors and patients to the risk of radiation-related cancer when compared to the likely benefits of treatment... modifying studies [However] the second cancer risks from newer radiation therapy treatments such as intensity modulated radiation therapy requires...."

Notes* 15 solid cancer sites, which routinely treated with radiation therapy were analyzed oral and salivary gland, rectum, anus, throat, larynx, lung, soft tissue, female breast, cervix, endometrial, prostate, testes, eye and orbit, brain and CNS and thyroid. link to the article

Source of the Lancet Oncology