ANNUAL MAMMOGRAPHY ADEQUATE AFTER BREAST CONSERVING SURGERY

May 11, 2012 (Phoenix, Arizona) — Mammography for ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery at 1-year intervals is likely sufficient, according to research presented here at the American Society of Breast Surgeons 13th Annual Meeting.

IBTR is uncommon in the first 2 years after surgery; however, many institutions have protocols calling for mammography every 6 months during the initial 2 years, said coauthor Tricia Merrigan, MD, a surgeon from Aultman Hospital, in Canton, Ohio.

"Mammography is clearly an important surveillance tool in detecting ipsilateral breast cancer recurrence after breast-conserving surgery, but there is no consensus on the optimal time interval for short-term imaging evaluation of these patients," Dr. Merrigan noted.

To determine rates of recurrence, Dr. Merrigan and her team evaluated the chart and mammography records of 375 patients who had undergone breast-conserving surgery at Aultman Hospital from January 2006 to December 2008.

The center has a protocol for patients who have undergone breast-conserving surgery: ipsilateral mammograms on the affected side at around 6 and 18 months and bilateral mammograms at around 12 and 24 months.

Study participants had been diagnosed with invasive primary breast carcinoma or ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (with or without postoperative breast radiation), and had at least 1 postoperative surveillance mammogram at the center.

All mammograms that were Breast Imaging-Reporting and Data System (BI-RADS) 0 or 4 were reviewed by a single radiologist. Among the patients (median age, 63 years), 67% had invasive ductal carcinomas, 26% had DCIS, and 6% had invasive lobular carcinomas.

Estrogen-receptor status was positive in 80% of the patients and progesterone-receptor status was positive in 63%. HER2 status was available for 278 of 280 patients with invasive cancer, and was positive in 21%.

Of patients with invasive cancer, 26% had positive axillary nodes. As treatment, 35% received neoadjuvant chemotherapy, 68% received hormonal therapy, and 91% received breast radiation.

Each additional mammographic screening (the 6- and 18-month mammograms) resulted in additional imaging for 3% to 4% of patients.

The IBTR yield was very low — 1 of 266 (0.4%) for the postoperative mammogram done at around 6 months and 1 of 286 (0.3%) for the postoperative mammogram done at around 18 months.

"Based on our data and the low expected yield of IBTR in the first 2 years after breast-conservation surgery, it appears that annual mammographic surveillance would be adequate," Dr. Merrigan said.

"Interval ipsilateral mammograms at 6 and 18 months do not provide additional clinical benefit." Dr. Merrigan added that her center is considering changing its policy to an annual mammogram protocol.

According to breast surgeon Hiram S. Cody III, MD, attending surgeon at Memorial Sloan-Kettering. Cancer Center and professor of clinical surgery at Weill Cornell Medical College in New York City, the findings underscore an issue that warrants scrutiny.

"Many radiologists recommend that mammography for breast-conservation patients be done every 6 months for 2 to 3 years after surgery. The problem is that at 6 months postop, you always see dense scarring, which resembles cancer, causes patient anxiety, and requires yet another 6 months of follow-up to confirm resolution."

"It makes much more sense to let the operative scarring resolve on its own and do mammograms annually," he said.

"This study supports that approach, deserves the attention of the radiology community, and challenges them to justify a widespread practice that does not appear to benefit patients," Dr. Cody said.

Dr. Merrigan and Dr. Cody have disclosed no relevant financial relationships.

American Society of Breast Surgeons (ASBS) 13th Annual Meeting: Abstract  0251. Presented May 5, 2012.