The MammoSite catheter is a bracytherapy device used for accelerated partial
breast irradiation. It is available as two spherically shaped balloons
meant to fill 70-cc and 120-cc cavity volumes. The authors conducted a
study to define the relationship between these excision volumes and the
likelihood of microscopically detectable, residual disease based on tumor
size, margin status, patient age, and histology. The study database was
composed of 531 patients with stages 0, I, and II breast carcinoma (using
American Joint Committee on Cancer staging criteria) who received breast-conserving
therapy and underwent surgical re-excision. Patients in the database were
stratified based on the volume of their initial excision: less than or
equal to 70 cc versus greater than 70 cc, and less than or equal to 120
cc versus greater than 120 cc. The authors found that surgical margin
size was a strong predictor of residual disease for patients with smaller
excision volumes (P=0.0014) and patients with larger excision
volumes (P=0.0003). Histology (extensive intraductal component
[EIC] or pure ductal carcinoma in situ [DCIS]) was also a strong predictor
of residual disease. Tumor size was significant only for the larger volume
group (P=0.029). On multivariate analysis, only histology and
initial margin status were significant correlates with residual disease.
The adjusted odds ratio for residual disease with pure DCIS was 0.79,
and the adjusted odds ratio for invasive ductal or lobular carcinoma (IDC/ILC)
without EIC was 0.44 relative to IDC/ILC with EIC (P=0.008).
The adjusted odds ratio for residual disease with a positive initial margin
versus a negative initial margin was 2.65 (P<0.0001).
The authors concluded that for excisions amenable to use of the MammoSite
catheter, a margin of greater than or equal to 1.0 mm appeared to afford
at most a 35 percent risk of microscopically detectable residual tumor.
Evidence of EIC on excision of IDC/ILC connoted a significantly higher
risk. Age did not appear to be predictive for residual disease.
Kaufman SA, DiPetrillo TA, Ruthazer R, et al. MammoSite excision volume as
a predictor for residual disease. Cancer.
Reprints: Dr. Seth A. Kaufman, Dept. of Radiation Oncology, Tufts-New
England Medical Center, Box 359, Boston, MA 02111; email@example.com
Allelic losses of 1p and 19q arms correlate with the oligodendroglial phenotype as well as with sensitivity to radiotherapy and chemotherapy. Furthermore, the DNA repair gene methylguanine methyltransferase (MGMT) is diminished in 80 percent of oligodendroglial tumors and represents a possible mechanism for this therapeutic sensitivity. However, the authors of this study questioned the relevance of genetic testing and measuring MGMT levels in tumors that were diagnostic of oligodendroglioma. They performed a retrospective analysis of 1p, 19q, 9p21, TP53, and MGMT status in 46 patients with oligodendrogliomas to address any relationships that may exist between these markers with regard to progression-free survival and total survival. Methodologies included comparative genomic hybridization; loss of heterozygosity (LOH) on 1p, 19q, and 9p21; TP53 mutational analysis; and immunohistochemistry for MGMT. The authors found that survival among patients with light microscopically diagnosed oligodendroglial tumors demonstrating LOH of 1p and 19q trended toward statistical significance (P=0.102 and P=0.058, respectively). 9p21 LOH was significant as a predictor of progression-free survival only among anaplastic oligodendrogliomas in this cohort (P=0.033). TP53 mutation was found to be significantly predictive of a shorter survival (P=0.027) among all patients and exhibited a strong trend toward a shorter progression-free survival (P=0.060). Low-level MGMT labeling index (less than 20 percent) was noted in 86 percent of all oligodendroglial tumors. MGMT labeling index was not found to correlate with an improved progression-free survival or total survival in this cohort, recognizing that median survival was not reached after a median followup of 104 months. The authors concluded that 9p21 and TP53 mutational status assisted in developing a stricter subclassification of these tumors with prognostic significance. MGMT levels were decreased in a majority of oligodendrogliomas.
McLendon RE, Herndon JE, West B, et al. Survival analysis of presumptive prognostic
markers among oligodendrogliomas.
Reprints: Dr. Roger E. McLendon, Dept. of Pathology, Duke University
Medical Center, P.O. Box 3712, Durham, NC 27710; firstname.lastname@example.org
The authors conducted a study to see if multiple tumors in the breast
are associated with increased nodal involvement when compared with similar
staged unifocal disease. Their study compared two methods of tumor size
assessment to predict tumor behavior in the relationship between size
and axillary node involvement for patients with multifocal and multicentric
breast cancer. The authors examined the histologic reports of every patient
with multifocal breast cancer treated in New South Wales between April
1995 and September 1995. Tumors were assessed using the largest tumor
focus diameter and the aggregate diameters of all tumor foci. The dimensions
were compared with unifocal tumors and against nodal positivity. The authors
found that 94 (11.1 percent) of 848 women had multifocal breast cancer,
and of these, 49 women (52.1 percent) had axillary node involvement, compared
with 37.5 percent with unifocal breast cancer (P=0.007). The
use of aggregate dimension reclassified significant numbers of multifocal
tumors at a more advanced stage. Using this method to stage cancers, rather
than largest tumor size, removed the excess node positivity when compared
with unifocal, stage-matched breast carcinomas. The authors concluded
that the tendency of breast tumors to metastasize is a reflection of the
total tumor load. Failure to measure the additional tumor burden provided
by multiple small foci may understage a woman’s disease. This may deny
patients the opportunity of adjuvant therapies if doctors ignore the contribution
of the smaller foci to the incidence of node positivity and survival.
Coombs NJ, Boyages J. Multifocal and multicentric breast cancer: Does each
J Clin Oncol. 2005;23:7497-7502.
Reprints: John Boyages, New South Wales Breast Cancer Institute, Westmead
Hospital, Westmead, Sydney, NSW 2145, Australia; email@example.com
Dr. Cibull is professor of pathology and laboratory medicine and direct of surgical pathology, University of Kentucky Medical Center, Lexington. Dr. Lele is assistant professor of pathology and laboratory medicine, University of Kentucky Medical Center. Dr. Kesler is hematopathology fellow, University of Texas Southwestern Medical Center at Dallas.