Radioactive Seeds Guide Surgeons to Nonpalpable Breast Lesions

WASHINGTON – Radioactive seeds were a safe and effective method of pinpointing nonpalpable breast lesions for surgery, with an 85% rate of negative margins on the first excision and an ipsilateral recurrence rate of less than 2% over 33 months, according to a large retrospective study.

Close margins occurred in 12% of the 767 patients with nonpalpable breast lesions, and positive margins occurred in 3%. The overall re-excision rate was 15%, Dr. Lee McGhan of the Mayo Clinic, Scottsdale, Ariz., said at the annual meeting of the American Society of Breast Surgeons.

Performing the procedure is "almost intuitive," with a very low learning curve, he said. "It is now our method of choice when dealing with preoperative localization of nonpalpable breast lesions."

His retrospective review of 978 prospectively collected patient records comprised 1,000 radioactive in 2003-2010. Almost 1,150 seeds were deployed.

The patients’ mean age was 65 years; their mean lesion size was 1.2 cm. Most (550) had an invasive carcinoma; 217 had DCIS (ductal carcinoma in situ); 115 had atypical hyperplasia, and the remainder, uncertain or suspicious percutaneous biopsy results.

Dr. McGhan reported 33-month follow-up results on the 767 women with either invasive carcinoma or DCIS. Most patients (910) received just one seed; 84 received two seeds; 5 received three seeds; and 1 patient received four of the devices.

Most (76%) underwent the procedure at least 1 day before surgery. Typically, Dr. McGhan said, patients came to the clinic a few days before surgery for an evaluation. Many chose to have the localization on a Friday, stayed over the weekend, and had the seeds removed early on Monday morning.

The 4- to 5-mm seeds containing radioactive iodine-125 can be placed up to 5 days before surgery. They were deployed through an 18-gauge spinal needle under image guidance; post deployment, a mammogram or ultrasound confirmed their position near the lesion. "We used a handheld gamma probe to identify the area of greatest radioactivity at the skin surface, marking the optimal site of skin incision," Dr. McGhan said.

Intraoperative complications included 30 displaced seeds – including 3 suctioned up by operative tubing and 3 that were improperly deployed during radiology – as well as one instance of an incorrect incision site resulting from a miscommunication between the radiologist and the surgeon, Dr. McGhan said. All of these seeds were retrieved with no patient harm.

All of the localized lesions were successfully removed, along with their associated seeds; the specimens were sent to pathology. Among the 550 invasive cancers, margins were negative in 87%, close in 9%, and positive in 3%. Re-excision was required in 13% (69).

Among the 217 DCIS lesions, margins were negative in 77%, close in 19%, and positive in 3%. Re-excision was necessary in 23% (49).

Sentinel node biopsies occurred in 544 cases, and were successful in all but one, Dr. McGhan said. "There was no blue dye detected, which was determined to be due to tumor invasion of the lymphatics rather than a direct complication of the procedure."

The mean follow-up period was 33 months. Over this time, the overall ipsilateral recurrence rate was 1.6% (12 patients). The rate was slightly higher among patients with DCIS (3%; seven patients). The local recurrence rate was 1% (five patients) among those with invasive cancer. By the end of the follow-up period, there were six mastectomies secondary to recurrence: three (0.5%) in the invasive cancer group and three (1%) in the DCIS group.

Dr. McGhan had no financial declarations.

WASHINGTON – Radioactive seeds were a safe and effective method of pinpointing nonpalpable breast lesions for surgery, with an 85% rate of negative margins on the first excision and an ipsilateral recurrence rate of less than 2% over 33 months, according to a large retrospective study.

Close margins occurred in 12% of the 767 patients with nonpalpable breast lesions, and positive margins occurred in 3%. The overall re-excision rate was 15%, Dr. Lee McGhan of the Mayo Clinic, Scottsdale, Ariz., said at the annual meeting of the American Society of Breast Surgeons.

Performing the procedure is "almost intuitive," with a very low learning curve, he said. "It is now our method of choice when dealing with preoperative localization of nonpalpable breast lesions."

His retrospective review of 978 prospectively collected patient records comprised 1,000 radioactive in 2003-2010. Almost 1,150 seeds were deployed.

The patients’ mean age was 65 years; their mean lesion size was 1.2 cm. Most (550) had an invasive carcinoma; 217 had DCIS (ductal carcinoma in situ); 115 had atypical hyperplasia, and the remainder, uncertain or suspicious percutaneous biopsy results.

Dr. McGhan reported 33-month follow-up results on the 767 women with either invasive carcinoma or DCIS. Most patients (910) received just one seed; 84 received two seeds; 5 received three seeds; and 1 patient received four of the devices.

Most (76%) underwent the procedure at least 1 day before surgery. Typically, Dr. McGhan said, patients came to the clinic a few days before surgery for an evaluation. Many chose to have the localization on a Friday, stayed over the weekend, and had the seeds removed early on Monday morning.

The 4- to 5-mm seeds containing radioactive iodine-125 can be placed up to 5 days before surgery. They were deployed through an 18-gauge spinal needle under image guidance; post deployment, a mammogram or ultrasound confirmed their position near the lesion. "We used a handheld gamma probe to identify the area of greatest radioactivity at the skin surface, marking the optimal site of skin incision," Dr. McGhan said.

Intraoperative complications included 30 displaced seeds – including 3 suctioned up by operative tubing and 3 that were improperly deployed during radiology – as well as one instance of an incorrect incision site resulting from a miscommunication between the radiologist and the surgeon, Dr. McGhan said. All of these seeds were retrieved with no patient harm.

All of the localized lesions were successfully removed, along with their associated seeds; the specimens were sent to pathology. Among the 550 invasive cancers, margins were negative in 87%, close in 9%, and positive in 3%. Re-excision was required in 13% (69).

Among the 217 DCIS lesions, margins were negative in 77%, close in 19%, and positive in 3%. Re-excision was necessary in 23% (49).

Sentinel node biopsies occurred in 544 cases, and were successful in all but one, Dr. McGhan said. "There was no blue dye detected, which was determined to be due to tumor invasion of the lymphatics rather than a direct complication of the procedure."

The mean follow-up period was 33 months. Over this time, the overall ipsilateral recurrence rate was 1.6% (12 patients). The rate was slightly higher among patients with DCIS (3%; seven patients). The local recurrence rate was 1% (five patients) among those with invasive cancer. By the end of the follow-up period, there were six mastectomies secondary to recurrence: three (0.5%) in the invasive cancer group and three (1%) in the DCIS group.

Dr. McGhan had no financial declarations.

WASHINGTON – Radioactive seeds were a safe and effective method of pinpointing nonpalpable breast lesions for surgery, with an 85% rate of negative margins on the first excision and an ipsilateral recurrence rate of less than 2% over 33 months, according to a large retrospective study.

Close margins occurred in 12% of the 767 patients with nonpalpable breast lesions, and positive margins occurred in 3%. The overall re-excision rate was 15%, Dr. Lee McGhan of the Mayo Clinic, Scottsdale, Ariz., said at the annual meeting of the American Society of Breast Surgeons.

Performing the procedure is "almost intuitive," with a very low learning curve, he said. "It is now our method of choice when dealing with preoperative localization of nonpalpable breast lesions."

His retrospective review of 978 prospectively collected patient records comprised 1,000 radioactive in 2003-2010. Almost 1,150 seeds were deployed.

The patients’ mean age was 65 years; their mean lesion size was 1.2 cm. Most (550) had an invasive carcinoma; 217 had DCIS (ductal carcinoma in situ); 115 had atypical hyperplasia, and the remainder, uncertain or suspicious percutaneous biopsy results.

Dr. McGhan reported 33-month follow-up results on the 767 women with either invasive carcinoma or DCIS. Most patients (910) received just one seed; 84 received two seeds; 5 received three seeds; and 1 patient received four of the devices.

Most (76%) underwent the procedure at least 1 day before surgery. Typically, Dr. McGhan said, patients came to the clinic a few days before surgery for an evaluation. Many chose to have the localization on a Friday, stayed over the weekend, and had the seeds removed early on Monday morning.

The 4- to 5-mm seeds containing radioactive iodine-125 can be placed up to 5 days before surgery. They were deployed through an 18-gauge spinal needle under image guidance; post deployment, a mammogram or ultrasound confirmed their position near the lesion. "We used a handheld gamma probe to identify the area of greatest radioactivity at the skin surface, marking the optimal site of skin incision," Dr. McGhan said.

Intraoperative complications included 30 displaced seeds – including 3 suctioned up by operative tubing and 3 that were improperly deployed during radiology – as well as one instance of an incorrect incision site resulting from a miscommunication between the radiologist and the surgeon, Dr. McGhan said. All of these seeds were retrieved with no patient harm.

All of the localized lesions were successfully removed, along with their associated seeds; the specimens were sent to pathology. Among the 550 invasive cancers, margins were negative in 87%, close in 9%, and positive in 3%. Re-excision was required in 13% (69).

Among the 217 DCIS lesions, margins were negative in 77%, close in 19%, and positive in 3%. Re-excision was necessary in 23% (49).

Sentinel node biopsies occurred in 544 cases, and were successful in all but one, Dr. McGhan said. "There was no blue dye detected, which was determined to be due to tumor invasion of the lymphatics rather than a direct complication of the procedure."

The mean follow-up period was 33 months. Over this time, the overall ipsilateral recurrence rate was 1.6% (12 patients). The rate was slightly higher among patients with DCIS (3%; seven patients). The local recurrence rate was 1% (five patients) among those with invasive cancer. By the end of the follow-up period, there were six mastectomies secondary to recurrence: three (0.5%) in the invasive cancer group and three (1%) in the DCIS group.

Dr. McGhan had no financial declarations.