- Email: [email protected]
New possibilities of diagnostic imaging and intervention
New Possibilities of Diagnostic Imaging and Intervention arly detection by increased use of imaging allows a mortality reduction of approximately 35% (WHO press release 18-3-02 www.iarc.fr), but it also leads to the detection of approximately 3 times more suspicious, eventually benign lesions than cancers. Diagnostic surgical biopsy of such a high number of lesions is neither sensible nor cost-effective. Thus percutaneous biopsy is increasingly used to avoid diagnostic surgical biopsy of indeterminate and probably benign lesions. Fine needle biopsy (FNB) has been used in some countries for workup of such lesions. However, its sensitivity varies between 53% and 98% (average 83%). Core needle biopsy (CNB) yields a better accuracy of 92% to 98% (average 95%).1 However, here, too, 5% to 10% falsenegatives occur. If, however, a negative percutaneous biopsy with a sensitivity of 90% were relied on, one of 10 cancers might be missed. False-negatives appear to be more frequent in cases with microcalcifications, architectural distortion, and probably small masses. Reasons for errors include stereotactic error, lesion shift during needle insertion, or sampling error. Vacuum biopsy (VB) is a new method, which, based on its unique principle, promises to avoid most above mentioned problems: Tissue is suctioned into the probe, then cut off by a rotating knife. The acquired tissue core is transported to the back part of the probe, where it can be picked off, while the probe stays in the lesion. Any bleeding is suctioned off and thus avoids pushing of the lesion away from the biopsy needle by a hematoma. By repeated tissue acquisition and by turning the probe around its axis, it is possible to remove an area of suspicion of approximately 1.5 cm (Fig 1). A special advantage of VB concerns the fact that partial or complete lesion removal is in most cases visualized on the postinterventional images. This allows a direct countercheck of correct excision. Several authors have pointed out its excellent diagnostic accuracy, improved
E
Curr Probl Cancer 2003;27:32-38. 0147-0272/2003/$35.00 ⫹ 0 56/1/5 doi:10.1067/mcn.2003.5
32
Curr Probl Cancer, January/February 2003
results concerning classification of ADH versus DCIS versus invasive carcinoma, and excellent patient tolerance.2-5 In a German multicenter study,6 2400 stereotactic VB were performed for predominantly indeterminate small lesions (60% lesions ⬍1 cm). Highly suspicious lesions instead mostly underwent sonographically guided core needle biopsy or surgical biopsy. Twenty-two percent of the lesions were malignant; 60% of the malignancies were DCIS, indicating preselection of discrete and early changes. All 22% malignancies and an additional 5% of ADH or LCIS underwent reexcision, whereas surgery could be avoided in more than 98% of the benign lesions. So far, 6 to 60 months of follow-up of the benign lesions showed one false-negative in a case with architectural distortion, an indication for which we would today recommend open biopsy. Based on its excellent negative predictive value of 99.8%, which even exceeds that of surgical biopsy, VB is very reliable. It allows avoidance of surgery in the vast majority of benign lesions and thus proves to be cost-effective. It was very well tolerated by 95% of the patients and only led to a small mammographic scar in 0.2% of cases. Whenever malignancy is confirmed, optimum local staging is important before breast-conserving surgery to avoid residual disease. So far, mammography and ultrasound have been used for this purpose. According to the present literature, however, additional therapeutically important information becomes available with the use of contrast-enhanced MRI. Because of its unique sensitivity for even enhancing small tumors, MRI is increasingly accepted in the following indication if assessment by conventional imaging is impaired7: Staging before breast conservation. Advantages include improved therapy planning by more accurate assessment of extent and multicentricity in 15% to 20% of cases. MRI can significantly improve breast cancer detection in patients with carcinoma of unknown primary site (CUP) syndrome. In patients with difficult-to-assess breast tissue after breast-conserving therapy, up to 46% of recurrences could be detected by MRI alone. After silicon implantation up to 47% of the recurrent malignancies could be detected by MRI alone. The mean size of malignant foci, which were only visible by MRI, was 9.3 mm versus 17.4 mm for foci, which were detectable by conventional breast diagnosis as well. In patients with a high risk of breast cancer, preliminary results of 4 studies have shown that additional malignancies are detected by MRI alone.8 Whenever a lesion is detected by MRI alone, MR guidance is needed Curr Probl Cancer, January/February 2003
33
FIG 1. Vacuum-assisted biopsy of indeterminate microcalcifications: a, mammogram before VB; b, probe positioned with microcalcifications directly ahead (prefire); c, microcalcifications largely covered by the probe (postfire); d, after VB the microcalcifications are removed from the breast. Histology: benign changes with secretory psammomatous microcalcifications.
34
Curr Probl Cancer, January/February 2003
FIG. 1. Continued.
Curr Probl Cancer, January/February 2003
35
FIG 2. Status after breast-conserving therapy 3 years prior. a, MR-detected suspicious enhancement within the scar (subtraction image: after contrast minus before contrast image); b, needle in place, piercing the lesion; c, postcontrast image after CM: the lesion is no more visible, the cavity (black) has partly collapsed. Histology: recurrence of a ductal carcinoma.
36
Curr Probl Cancer, January/February 2003
FIG. 2. Continued.
for histopathologic workup of MR-detected lesions. Various add-on equipment has been developed to allow preoperative MR-guided wire localization. A major problem so far concerned the lack of specimen imaging. (Contrast enhancement cannot be visualized in specimens.) Furthermore, timing of the MR localization procedure and subsequent surgery may be problematic, whereas 60% to 80% of the lesions prove to be benign. MR-guided CNB has been performed by some investigators. However, monitoring is impaired by problems of space within the magnet and by artifacts, which are caused by the usually recommended needle thickness. Therefore reliability of percutaneous CNB is mostly considered uncertain for lesions ⬍1 cm, unless a specific histology is obtained. In 1997, we introduced a new method, which promised to solve problems of MR-guided percutaneous biopsy (Fig 2): MR-guided percutaneous VB (MR-VB).9 MR-VB became possible by a specially designed device that allows guidance of a VB probe into the fixed breast under MR guidance. The method offers the following advantages: acquisition of larger tissue volume, thus compensation for tissue shift due to needle insertion and avoidance of sampling error. Since blood is also evacuated and since removal of the enhancing tissue can usually be proven directly after VB, an additional countercheck for correct incisional, or even Curr Probl Cancer, January/February 2003
37
excisional, biopsy exists. The method has no limitations concerning small-sized lesions. The first results of a large European multicenter study (EC project BMH 4- CT-3741, Biomed 2) on MR-guided VB are presented. Ninety-six percent of the procedures (⬎500), performed at 5 sites, were successful. The 4% unsuccessful biopsy procedures were all correctly recognized, since directly after biopsy, the enhancing lesion was visualized beside the biopsy cavity. So far, no false-negative calls occurred. Overall, 29% of malignant or borderline lesions were verified. In 98% of the 362 biopsy specimens of benign lesions, surgery could be avoided. Thus MR-VB proved to be a reproducible, very accurate, minimally invasive method for histologic work-up of MR-detected enhancing lesions.
REFERENCES 1. 2.
3. 4. 5.
6.
7. 8.
9.
38
Britton PD. Fine needle aspiration or core biopsy. Breast 1999;8:1-4. Burbank F. Mammographic findings after 14-gauge automated needle and 14-gauge directional, vacuum-assisted stereotactic breast biopsies. Radiology 1997;204: 153-6. Heywang-Koebrunner SH, Schaumloffel U, Viehweg P, et al. Minimally invasive stereotaxic core breast biopsy. Eur Radiology 1998;8:377-85. Zannis VJ, Aliano KM. The evolving practice pattern of the breast surgeon with disappearance of open biopsy for nonpalpable lesions. Am J Surg 1998;176:525-8. Jackman RJ, Burbank F, Parker SH, et al. Stereotactic breast biopsy of nonpalpable lesions: determinants of ductal carcinoma in situ underestimation rates. Radiology 2001;218:497-502. Rotter, Kettritz U, Schreer I, et al. Multicenter evaluation of stereotactic vacuum biopsies of mammographically indeterminate or suspicious lesions. Eur Radiol 2002;12(suppl 1):316. Heywang-Kobrunner SH, Viehweg P, Heinig A, et al. Contrast-enhanced MRI of the breast: accuracy, value, controversies, solutions. Eur J Radiol 1997;24:94-108. Stoutjesdijk MJ, Boetes C, Jager GJ, et al. Magnetic resonance imaging and mammography in women with a hereditary risk of breast cancer. J Natl Cancer Inst 2001;93:1095-102. Heywang-Kobrunner SH, Heinig A, Pickuth D, et al. Interventional MRI of the breast: lesion localisation and biopsy. Eur Radiol 2000;10:36-45.
Curr Probl Cancer, January/February 2003
E
Curr Probl Cancer 2003;27:32-38. 0147-0272/2003/$35.00 ⫹ 0 56/1/5 doi:10.1067/mcn.2003.5
32
Curr Probl Cancer, January/February 2003
results concerning classification of ADH versus DCIS versus invasive carcinoma, and excellent patient tolerance.2-5 In a German multicenter study,6 2400 stereotactic VB were performed for predominantly indeterminate small lesions (60% lesions ⬍1 cm). Highly suspicious lesions instead mostly underwent sonographically guided core needle biopsy or surgical biopsy. Twenty-two percent of the lesions were malignant; 60% of the malignancies were DCIS, indicating preselection of discrete and early changes. All 22% malignancies and an additional 5% of ADH or LCIS underwent reexcision, whereas surgery could be avoided in more than 98% of the benign lesions. So far, 6 to 60 months of follow-up of the benign lesions showed one false-negative in a case with architectural distortion, an indication for which we would today recommend open biopsy. Based on its excellent negative predictive value of 99.8%, which even exceeds that of surgical biopsy, VB is very reliable. It allows avoidance of surgery in the vast majority of benign lesions and thus proves to be cost-effective. It was very well tolerated by 95% of the patients and only led to a small mammographic scar in 0.2% of cases. Whenever malignancy is confirmed, optimum local staging is important before breast-conserving surgery to avoid residual disease. So far, mammography and ultrasound have been used for this purpose. According to the present literature, however, additional therapeutically important information becomes available with the use of contrast-enhanced MRI. Because of its unique sensitivity for even enhancing small tumors, MRI is increasingly accepted in the following indication if assessment by conventional imaging is impaired7: Staging before breast conservation. Advantages include improved therapy planning by more accurate assessment of extent and multicentricity in 15% to 20% of cases. MRI can significantly improve breast cancer detection in patients with carcinoma of unknown primary site (CUP) syndrome. In patients with difficult-to-assess breast tissue after breast-conserving therapy, up to 46% of recurrences could be detected by MRI alone. After silicon implantation up to 47% of the recurrent malignancies could be detected by MRI alone. The mean size of malignant foci, which were only visible by MRI, was 9.3 mm versus 17.4 mm for foci, which were detectable by conventional breast diagnosis as well. In patients with a high risk of breast cancer, preliminary results of 4 studies have shown that additional malignancies are detected by MRI alone.8 Whenever a lesion is detected by MRI alone, MR guidance is needed Curr Probl Cancer, January/February 2003
33
FIG 1. Vacuum-assisted biopsy of indeterminate microcalcifications: a, mammogram before VB; b, probe positioned with microcalcifications directly ahead (prefire); c, microcalcifications largely covered by the probe (postfire); d, after VB the microcalcifications are removed from the breast. Histology: benign changes with secretory psammomatous microcalcifications.
34
Curr Probl Cancer, January/February 2003
FIG. 1. Continued.
Curr Probl Cancer, January/February 2003
35
FIG 2. Status after breast-conserving therapy 3 years prior. a, MR-detected suspicious enhancement within the scar (subtraction image: after contrast minus before contrast image); b, needle in place, piercing the lesion; c, postcontrast image after CM: the lesion is no more visible, the cavity (black) has partly collapsed. Histology: recurrence of a ductal carcinoma.
36
Curr Probl Cancer, January/February 2003
FIG. 2. Continued.
for histopathologic workup of MR-detected lesions. Various add-on equipment has been developed to allow preoperative MR-guided wire localization. A major problem so far concerned the lack of specimen imaging. (Contrast enhancement cannot be visualized in specimens.) Furthermore, timing of the MR localization procedure and subsequent surgery may be problematic, whereas 60% to 80% of the lesions prove to be benign. MR-guided CNB has been performed by some investigators. However, monitoring is impaired by problems of space within the magnet and by artifacts, which are caused by the usually recommended needle thickness. Therefore reliability of percutaneous CNB is mostly considered uncertain for lesions ⬍1 cm, unless a specific histology is obtained. In 1997, we introduced a new method, which promised to solve problems of MR-guided percutaneous biopsy (Fig 2): MR-guided percutaneous VB (MR-VB).9 MR-VB became possible by a specially designed device that allows guidance of a VB probe into the fixed breast under MR guidance. The method offers the following advantages: acquisition of larger tissue volume, thus compensation for tissue shift due to needle insertion and avoidance of sampling error. Since blood is also evacuated and since removal of the enhancing tissue can usually be proven directly after VB, an additional countercheck for correct incisional, or even Curr Probl Cancer, January/February 2003
37
excisional, biopsy exists. The method has no limitations concerning small-sized lesions. The first results of a large European multicenter study (EC project BMH 4- CT-3741, Biomed 2) on MR-guided VB are presented. Ninety-six percent of the procedures (⬎500), performed at 5 sites, were successful. The 4% unsuccessful biopsy procedures were all correctly recognized, since directly after biopsy, the enhancing lesion was visualized beside the biopsy cavity. So far, no false-negative calls occurred. Overall, 29% of malignant or borderline lesions were verified. In 98% of the 362 biopsy specimens of benign lesions, surgery could be avoided. Thus MR-VB proved to be a reproducible, very accurate, minimally invasive method for histologic work-up of MR-detected enhancing lesions.
REFERENCES 1. 2.
3. 4. 5.
6.
7. 8.
9.
38
Britton PD. Fine needle aspiration or core biopsy. Breast 1999;8:1-4. Burbank F. Mammographic findings after 14-gauge automated needle and 14-gauge directional, vacuum-assisted stereotactic breast biopsies. Radiology 1997;204: 153-6. Heywang-Koebrunner SH, Schaumloffel U, Viehweg P, et al. Minimally invasive stereotaxic core breast biopsy. Eur Radiology 1998;8:377-85. Zannis VJ, Aliano KM. The evolving practice pattern of the breast surgeon with disappearance of open biopsy for nonpalpable lesions. Am J Surg 1998;176:525-8. Jackman RJ, Burbank F, Parker SH, et al. Stereotactic breast biopsy of nonpalpable lesions: determinants of ductal carcinoma in situ underestimation rates. Radiology 2001;218:497-502. Rotter, Kettritz U, Schreer I, et al. Multicenter evaluation of stereotactic vacuum biopsies of mammographically indeterminate or suspicious lesions. Eur Radiol 2002;12(suppl 1):316. Heywang-Kobrunner SH, Viehweg P, Heinig A, et al. Contrast-enhanced MRI of the breast: accuracy, value, controversies, solutions. Eur J Radiol 1997;24:94-108. Stoutjesdijk MJ, Boetes C, Jager GJ, et al. Magnetic resonance imaging and mammography in women with a hereditary risk of breast cancer. J Natl Cancer Inst 2001;93:1095-102. Heywang-Kobrunner SH, Heinig A, Pickuth D, et al. Interventional MRI of the breast: lesion localisation and biopsy. Eur Radiol 2000;10:36-45.
Curr Probl Cancer, January/February 2003