Breast imagers and surgeons continue to seek ways to treat breast cancer that are less invasive surgically and expose women to less radiation dose. Researchers presented studies addressing these issues in a press conference on Friday during the American Society of Breast Surgeons (ASBrS) annual meeting in Phoenix.
RF ablation: As good as radiation therapy?
Radiofrequency (RF) ablation of the lumpectomy site during breast cancer surgery can provide an effective alternative to postoperative external-beam radiation therapy, reducing repeat surgeries to clear tumor margins, according to researchers from the University of Arkansas for Medical Sciences.
Using RF ablation as a radiation therapy alternative is good news for a number of reasons, according to presenting author Dr. Misti Wilson: Not only does the technique avoid radiation's side effects such as breast tissue shrinkage and damage to nearby healthy tissue, it offers a far less invasive treatment for rural patients who may not have the option of radiation therapy -- and thus have no choice but mastectomy.
Wilson and colleagues found that using radiofrequency-generated heat to create an added disease-free zone around the tumor cavity is at least as effective in preventing local tumor recurrence as radiation therapy following surgery. In many cases, ablation extended the disease-free zone enough to eliminate the need for repeat surgery.
The study included 73 patients with invasive cancer but clinically negative nodes; tumor size was approximately 1 cm. All patients had a lumpectomy and radiofrequency ablation and were tracked for an average of 55 months. None of the patients had external radiation therapy.
Nineteen of the 73 patients had close positive margins, and three patients required a second surgery, according to Wilson. Eighty-seven percent of patients who would have returned to the operating room with similar margin findings and external radiation therapy were spared additional surgery, she said.
"Patients in this study did extremely well," Wilson said. "Without the side effects of radiation, radiofrequency ablation is an extremely appealing choice, especially since the ablated tissue remains in the breast, so less breast mass is lost than with radiation. The cosmetic results are excellent. Often, you can barely tell a patient has had surgery."
Based on the results of this study, RF ablation is now being examined in a multicenter trial, which to date includes five centers: Columbia University, University of Kansas, Comprehensive Breast Care of San Diego, University of Arizona, and Rockefeller Cancer Institute in Little Rock. Researchers are also actively recruiting and training additional sites, Wilson said.
Infrared thermography not ready for prime time
Meanwhile, infrared thermography, a nonradiation-based imaging modality that measures thermal abnormalities in breast tissue, is not a reliable breast cancer screening tool, researchers from Bryn Mawr Hospital found.
"We're all looking for ways to detect breast cancer with less radiation exposure and no contrast," said study presenter Dr. Andrea Barrio. "Unfortunately, [infrared thermography] is unable to discriminate between benign and malignant tumors and produces an unacceptable amount of false positives."
Barrio and colleagues examined 178 patients with abnormal results on mammography, ultrasound, or MRI who were undergoing minimally invasive breast biopsy for further evaluation. Patients' affected breasts were scanned using UE LifeSciences' NoTouch BreastScan (NTBS) infrared thermography system prior to minimally invasive biopsy. The company announced in March that the system received U.S. Food and Drug Administration (FDA) clearance.
The team used the device in both high-specificity and high-sensitivity modes, according to Barrio. All results were compared with pathology findings following biopsy.
In the high-specificity mode, of the 52 patients later identified with cancer, infrared imaging failed to pick up 26, producing a sensitivity of 50%. Sensitivity was lower with early-stage ductal carcinoma in situ (DCIS) than with invasive cancer. Of the 132 negative biopsies, 42 presented with positive findings on infrared thermography, for a specificity of 67%. The positive predictive value of infrared thermography was only 37%. Its negative predictive value was 77%.
In the high-sensitivity mode, infrared thermography correctly identified 44 of the 46 positive breast biopsies (sensitivity 87%). Of the 116 negative biopsies, 61 were incorrectly identified as positive (specificity 48%). Overall, the positive predictive value of infrared thermography was 40%, while the negative predictive value was 90%, Barrio's team found.
"Our research shows infrared thermography cannot be used as a successful adjunct to mammography, nor can it replace any of the screening modalities in standard practice today," she said.
Lumpectomy for high-risk, local cancers
In another presentation, women with high-risk tumors can be safely treated with lumpectomy if their tumors respond well to chemotherapy prior to surgery, researchers at the University of California, San Francisco found.
Presenter Dr. Elizabeth Cureton and colleagues examined cancer recurrence in areas near the original tumor site in high-risk women who received multidisciplinary cancer therapies. The group found that tumor biological characteristics, reflected in part by response to neoadjuvant chemotherapy, and not choice of mastectomy or breast-conserving lumpectomy, was the major determinant of cancer returning locally.
The study, part of the Investigation of Serial Studies to Predict Your Therapeutic Response With Imaging and Molecular Analysis (I-SPY) 1 trial, examined 206 patients classified as high risk. All patients had chemotherapy before surgery. Ninety women were treated with lumpectomy and 116 with mastectomy; the choice of surgical treatment and the use of postoperative radiation therapy were at the discretion of the treating physician.
Of the 206 patients enrolled in the study, only 14 (6.8%) had recurrences near the original tumor site, while 45 (21%) eventually developed cancers in other areas of the body, Cureton said. Tumor size and lymph node status at the times of diagnosis and of surgery were significantly associated with recurrence, and women who did not respond well to neoadjuvant chemotherapy were also more likely to recur, the team found.
Most significantly, local recurrence rates were not different in women who received lumpectomy compared to mastectomy.
"Our study shows that both local and distant breast cancer recurrence are affected by aggressive tumor biology rather than type of surgery," Cureton said.
Men's breast cancer mortality risk higher than women's
Finally, researchers from Bay Area Breast Surgeons in Oakland, CA, found that men have a significantly lower breast cancer survival rate than women, particularly for early-stage disease.
Although men account for only about 1% of all breast cancer cases, approximately 2,000 men will develop the disease every year -- and that number is large enough that a busy practicing breast cancer surgeon can expect to see one or more cases every year, according to presenter and lead author Dr. John Greif.
Greif and colleagues compared more than 13,000 male and 1,440,000 female breast cancer cases entered from 1998 to 2007 in the National Cancer Data Base (NCDB). The group found that the five-year survival rate for women overall was 83%, compared to 74% for men. Men with breast cancer were more often African-American and older, at age 63 at diagnosis, on average, Greif said.
The study also found that although men were more likely than women to have estrogen-positive tumors (88.3% compared to 78.2%), only 41% of men in the study were treated with antiestrogen medications, Greif said.
