Young Age and DCIS Tied to Increased Risk of Breast Tumor Recurrence
NEW YORK (Reuters Health) – In women ages 40 and younger, the presence of ductal carcinoma in situ (DCIS) next to an invasive tumor is associated with an increased risk of ipsilateral breast tumor recurrence (IBTR), according to a recently published study.
“In the early ’90s, the EORTC ran the ‘boost no-boost’ trial, randomizing 5,569 early-stage breast cancer patients treated with breast-conserving surgery and whole-breast irradiation between no boost and a 16-Gy boost. A third of the patients were included in a central pathology review,” said Dr. Conny Vrieling of Clinique de Grangettes in Geneva, Switzerland.
“The 10-year follow-up results of this subpopulation showed that young age and high-grade invasive carcinoma were the most important risk factors for IBTR,” she told Reuters Health by email.
“In this study, we re-analyzed with long-term follow-up the pathological prognostic factors related to IBTR, with a special focus on the evolution of these effects over time,” she explained.
As reported in JAMA Oncology, online September 8, Dr. Vrieling and colleagues analyzed data from 1,616 patients who had a microscopically complete resection and were followed for up to 20 years. There were 160 IBTR during the study period: 99 in the 801 women in the no-boost group and 61 in the 815 patients in the boost group.
“The 20-year cumulative incidence of IBTR was 34% for patients 40 years or younger, compared to (14% for those ages 41 to 50) and 11% for patients 50 years and older,” Dr. Vrieling said.
In addition, she noted, the IBTR incidence was 18% and 9% for tumors with and without DCIS, respectively.
Young age (p<0.001) and DCIS adjacent to the invasive tumor (HR= 2.15) were associated with an increased incidence of IBTR, "whereas the grade of the invasive tumor was not a significant factor anymore," Dr. Vrieling observed. "High-grade tumors relapsed more frequently only during the first five years, whereas the relative effect of age and presence of DCIS was stable over time."
Therefore, “patients with high-grade invasive tumors should be monitored closely, especially in the first five years,” while long-term follow-up is needed for patients with DCIS, she said.
She added, “In the high-risk population (patients up to age 50 with DCIS present), a radiotherapy boost dose of 16 Gy reduced the 20-year cumulative incidence of IBTR from 31% to 15% (HR=0.37).”
Taken together, “these results . . . underline the importance of long-term trial follow-up to estimate absolute effects accurately,” Dr. Vrieling concluded.
Dr. Laurie Cuttino of Virginia Commonwealth University in Richmond, coauthor of an accompanying editorial, told Reuters Health, “This analysis shows that younger patients . . . , those with high-grade tumors, and those with tumors which are not responsive to estrogen benefit most from the additional (‘boost’) dose of focused radiation. Older patients with low-grade tumors which are responsive to estrogen do not appear to benefit from the boost dose.”
“This is important data for radiation oncologists in that it will allow for greater personalization of treatment for individual patients,” she said by email.
Dr. Homayoon Sanati, medical director of the MemorialCare Breast Center at Orange Coast Memorial Medical Center in Fountain Valley, California, commented, “This is a very important study which addresses the risk of local recurrence for breast cancer. They have 20-year follow-up results, which is amazing.”
With respect to the clinical implications, Dr. Sanati told Reuters Health by email that the recommendation of closer monitoring for patients at higher risk would probably not change his group’s practice “since we are monitoring all of our patients closely.”
“They found that giving a radiation boost to the tumor bed reduced the rate of local recurrences,” he noted. “Our breast program’s radiation oncologist has been giving a boost to the tumor bed, and this study confirms the benefits of this boost.”
JAMA Oncol 2016.