Radiation Therapy May Be Unnecessary for Postmenopausal Patients with Early-stage Breast Cancer after Conservative Surgery
Postmenopausal women aged 55 to 75 with early-stage breast cancer can be safely treated with breast-conserving surgery without postoperative radiation therapy, according to a double-arm, prospective, randomized study presented this week at the American Society of Breast Surgeons Annual Meeting. The study found no statistically significant difference in the risk of local recurrence and overall survival between the two treatment groups.
The authors note that breast-conserving surgery accompanied by postsurgical radiation of the breast is the generally accepted choice for treatment of women with early-stage breast cancer. “We may be overtreating almost half of these patients,” said primary study author Corrado Tinterri, MD, of the Humanitas Cancer Center in Milan. He noted that select patients may be spared the potential side effects, poorer cosmetic results, direct and indirect costs, and inconvenience associated with breast radiation. The elimination of follow-up radiation represents a major change in current breast cancer treatment protocols.
Study Details
The study followed 749 patients treated in 11 medical centers across Italy for a median of 9 years. Women studied ranged in age from 55 to 75 and had a tumor size of 2.5 cm or less without an extensive intraductal component and without peritumoral vascular invasion. They were randomly assigned to either a group treated with surgery alone or surgery accompanied by postoperative breast irradiation (50 Gy plus 10 Gy boost). Tumor characteristics were well-balanced across the groups.
“Breast irradiation might be associated with undesirable side effects. Costs are significant not only to the medical system but also to the radiotherapy patient who is unable to return to work or an active lifestyle as quickly as patients not receiving the treatments,” Dr. Tinterri commented. Furthermore, “Women who receive radiation along with surgical resection may be unable to have satisfactory breast reconstruction if the tumor recurs and they are subsequently treated with mastectomy. In addition, many patients in rural or other isolated areas where radiotherapy is not available or who are unable to schedule lengthy radiation treatments receive a mastectomy instead of conservative surgery. This is because mastectomy generally is not accompanied by radiation.”
Significant Findings
Noting that the findings of the study are extremely significant, Dr. Tinterri stresses that they involve a specific group of patients meeting strict biologic criteria. “Age was an extremely important factor in the study’s findings. Prior research found that younger women did not respond as well without radiation therapy,” he says. “Also women with small and nonaggressive tumors respond well to treatment without radiation. These are women who do not have intraductal involvement, that is, who do not have a significant number of atypical cells that extend into the milk ducts surrounding the tumor. They are also patients whose tumor has not spread into blood and lymphatic vessels around the tumor.” For these patients, he says, the findings are extremely promising.
In the study, at a median follow-up of 108 months, 3.4% (12) of the group receiving radiation therapy experienced a breast cancer recurrence (7 in the index quadrant and 5 in the other quadrant), and 4.4 % in the group without radiation therapy. There was no statistically significant difference in the risk of local recurrence and death in the two treatment groups.
“The fact that the patients studied came from 11 medical facilities in different geographic regions of the country is also significant,” adds Dr. Tinterri. “This suggests that specific methods of surgery employed in a particular center and patient lifestyle variances do not account for the findings. Additionally, the randomized, prospective format of the study also makes the findings extremely reliable.”
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