Treatment benefits of radiotherapy outweigh small increased risk of developing a second cancer

March 29, 2011

The proportion of second cancers related to radiotherapy treatment for the first cancer in adulthood is small (about 8%), concludes an Article published Online First in The Lancet Oncology. The findings, from the first study to quantify the risk from routine radiation therapy for multiple first cancers*, suggest that most second cancers are due to other factors such as lifestyle and genetics.

With improvements in cancer survival, determining the long-term risks from treatments such as radiotherapy has become important. It is well established that radiotherapy treatment is associated with a risk of developing a second cancer, but until now, what proportion of second cancers might be related to radiotherapy was not known.

In this study, Amy Berrington de Gonzalez from the National Cancer Institute, Rockville, MD, USA and colleagues collected data on 647 672 adult cancer survivors (who survived for 5 years or longer) from the US Surveillance, Epidemiology and End Results (SEER) cancer registries. They calculated the long-term risk of second cancers from the radiotherapy treatment of first solid-cancer sites in these adults during a follow-up period of 30 years.

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

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

The estimated proportion of second cancers related to radiotherapy varied according to the site of the first cancer--from 4% for cancers of the eye and orbit to 24% for cancer of the testicles.

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

For every 1000 patients treated with radiotherapy the researchers estimated three excess radiation treatment-related cancers by 10 years after a first cancer diagnosis, and five excess cancers by 15 years. These risks, say the authors, are small compared with the likely treatment benefits.

The authors conclude: "These findings can be used by physicians and patients to put the risk of radiation-related cancer into perspective when compared with the probable benefits of the treatment...[however] Studies of the second-cancer risks from newer radiotherapy treatments such as intensity modulated radiotherapy...are still needed."
-end-


Lancet

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.