Women 70 years of age or older with early-stage breast cancer did not benefit from the addition of radiation therapy to breast-conserving surgery and tamoxifen, according to the findings of a phase III randomized trial released last week. The study results, presented May 20 in advance of the American Society of Clinical Oncology (ASCO) annual meeting, indicate that “death from breast cancer is a very rare event among [older] women with these small cancers,” said lead author Dr. Kevin Hughes of Massachusetts General Hospital in Boston. The trial was conducted by three NCI clinical trials cooperative groups: the Cancer and Leukemia Group B, Eastern Cooperative Oncology Group, and Radiation Therapy Oncology Group.

Between 1994 and 1999, the researchers enrolled 636 women in the trial; 319 received tamoxifen alone after surgery, and 317 received tamoxifen plus radiation therapy. All women had early-stage,estrogen-receptor-positive (ER-positive) disease that had not spread to the lymph nodes. The researchers followed the women for a median of 10.5 years after treatment.

Although adding radiation therapy to tamoxifen reduced the chance of cancer recurrence in the same breast by 6 percent, it did not affect overall survival, breast-cancer-specific survival, cancer spread, or the need for later mastectomy due to disease recurrence. The 10-year breast-cancer-specific survival was 98 percent for women receiving tamoxifen alone and 96 percent for women receiving tamoxifen plus radiation therapy.

“Older women often have small tumors that are ER-positive, without evidence of spread to the lymph nodes. This [study] is certainly practice-affirming and may be potentially practice changing,” said Dr. Douglas Blayney, president of ASCO. “Many [older] women…elect to defer radiation therapy. This gives us some comfort as physicians in supporting that decision…and maybe it will change the recommendations we make to our patients,” he concluded.

In perhaps the strongest epidemiologic research of its kind to date, a case-control study of invasive cutaneous melanoma, involving more than 2,200 participants, found that any use of indoor tanning devices increased melanoma risk, but the risk was highest among those who engaged in indoor tanning most frequently. The findings were published online May 27 in Cancer Epidemiology Biomarkers and Prevention.

The results—from the Skin Health Study, conducted between 2004 and 2009 in Minnesota, a state with documented high indoor tanning use—are the first to show a clear dose—response relationship, with melanoma risk increasing by as much as 200 percent when indoor tanning usage exceeded 50 hours, 100 sessions, or 10 years. Over the last decade or so, the commercial tanning industry has introduced a number of newer technologies, and these were found to further increase the melanoma risk. Compared with people who have never used indoor tanning devices, those who used high-speed/high-intensity devices experienced 2.9 times the risk, and using high-pressure devices led to 4.4 times the risk. High-speed/high-intensity devices emit mostly UVA radiation plus a small percentage of UVB radiation; high-pressure devices emit UVA radiation almost exclusively.

Dr. Margaret Tucker, director of NCI’s Human Genetics Program in the Division of Cancer Epidemiology and Genetics, lauded the study for its value to researchers and public health. “This study was designed to specifically investigate the role of tanning devices in melanoma risk. It is carefully done and analyzed. This is the most solid, substantive study to date to specifically address the tanning device issue and is an important contribution to the field,” said Dr. Tucker, who led research that established the first susceptibility genes for melanoma and the development of a melanoma risk assessment tool.

The design and quality of the research is significant because industry has used the limitations of earlier studies “to counter possible health concerns,” said lead author Dr. DeAnn Lazovich from the Masonic Cancer Center and the University of Minnesota. Using in-depth surveys and thorough follow-up phone interviews, the researchers were able to explore details of tanning bed use that had not been simultaneously examined in a study of this size and in a population with high use.

“The risk of melanoma was increased whether we looked at the age of diagnosis, gender, the body site of the tumor, time period of use, how we measured the amount, or the type of devices used,” explained Dr. Lazovich. “All of those pieces tell a very consistent story.”

While it may not be possible to definitively distinguish between the effects of UVA versus UVB radiation employed in different devices, “the evidence indicates that all of these approaches do harm: there is no such thing as a safe device,” she emphasized. “And you don’t have to actually get a burn to incur the higher risk from indoor tanning, though we know that often happens.”

In 2009, the International Agency for Research on Cancer classified tanning devices as carcinogenic, emphasizing the risk to those exposed to indoor tanning before age 36. The current study did not confirm increased susceptibility for younger ages, but did suggest that those who start younger would likely go on to a greater lifetime exposure and, thus, face higher risk.

A big part of putting these findings into action will come at the societal level, said Dr. Electra Paskett, associate director for population sciences at the Ohio State University Comprehensive Cancer Center. “We have to change the social norms, and there are ways to do that,” she said, citing the successful effort to reduce tobacco use.

Indoor tanning has indeed become a social norm. As the study authors noted in the paper, a recent analysis of policies and laws on indoor tanning in 116 large U.S. cities found that “the average number of tanning salons exceeded the average number of Starbucks or McDonald’s.” And Dr. Lazovich cited data from the American Cancer Society stating that, nationally, 35 percent of 17-year-old girls report indoor tanning use. An FDA advisory panel recommended in March that the agency consider age restrictions or parental consent requirements for children under 18.

“Given the findings on the 116 large U.S. cities, it will likely take stronger age restrictions rather than relying on parental consent,” said Anne Hartman, a biostatistician in NCI’s Risk Factors Monitoring and Methods Branch in the Division of Cancer Control and Population Sciences. “That study did not find an association between youth indoor tanning laws, which mainly consisted of various forms of parental consent, and lower indoor tanning use among teens.”

Changing behaviors, Dr. Paskett stressed, will also require action at the health care provider level, and not just among dermatologists. Providers should be “educating their patients about the risks of indoor tanning,” she said. Questions about tanning should be added to those about smoking, drinking, and other risk behaviors that clinicians commonly ask their patients, Dr. Paskett said.