Breast Neoplasms; Ethics; Health Services Research
Extensive Research Description
My research has focused on breast cancer and while it spans the spectrum of inquiry related to this disease process, the majority of it falls into several large themes:
Chest Wall Recurrence: I began to become very interested in chest wall recurrences (CWR) after mastectomy and did a number of studies in this area. Several findings were key and were significant contributions to the literature and in fact were practice changing.
(i) Prognosis: While it had previously been thought that all patients with CWR had a dismal prognosis, I was able to define a group in whom prognosis was not poor, and in whom aggressive management was warranted. I developed a clinical prediction model to assess prognosis in these patients. This is now widely used, and was quoted by every speaker in a plenary session at the American College of Surgeons on the management of CWR.
(ii) Reconstruction: I was able to demonstrate that patients who develop a CWR after having had breast reconstruction did not need to have their reconstruction taken down. This finding which allowed many women to maintain their reconstruction despite having a CWR won the best poster award at the Southwestern Surgical Congress.
(iii)Radiation: I defined not only the need for radiation therapy after CWR, but also added to the literature findings to support the use of post-mastectomy radiation therapy, which has now become widely accepted and supported by ASCO and ASTRO guidelines.
Sentinel Lymph Node Biopsy: Much of my work has focused on various issues surrounding sentinel lymph node biopsy (SLNB) in the management of breast cancer patients. I validated the subareolar injection technique in the world’s largest series (4131 patients); this is now considered by many to be the optimal injection technique for SLNB. I elucidated, in one of the most widely quoted studies, the association between immunohistochemically detected sentinel node deposits and prognosis, a study which won me an ASCO Merit Award. I identified factors associated with a failure to identify a sentinel lymph node, which has encouraged surgeons to use dual tracer technique to optimize identification rates. I explored the use of lymphoscintigraphy and the finding of internal mammary nodes (IMN), finding that positive IMN nodes frequently do not change prognosis or management – this is one of the oft-quoted studies for why many surgeons do not routinely use lymphoscintigraphy or do IMN biopsies. I published that there was no difference in SLN-positivity rates based on biopsy type – a study that contradicted the myth that core needle biopsy could spread cancer cells into lymph nodes. This was important as excisional biopsy is now considered suboptimal, and needle biopsies are favored. Having an extensive background in SLNB, I acquired skills in clinical prediction modeling through my MPH at Harvard, and created a number of clinical prediction rules which have now been validated in a number of studies. I consider these seminal contributions to the literature, as these prediction rules allow for the prediction of (i) non-sentinel node metastases in SLN-positive patients using preoperative and intraoperative factors alone, (ii) the finding of four or more positive SLNs in patients with tumors
Mammography and Screening in Population-Based Studies: I have worked extensively with the National Health Interview Survey to understand trends in mammography and screening in the US population. I was one of the first to demonstrate that the recent decline in breast cancer incidence rates was not due solely to a reduction in hormone replacement therapy use, but also to a decline in mammography screening. I defined the use of mammography in various racial cohorts, and analyzed mammography usage based on risk stratifications. This work was cited by the US Preventative Services Task Force in their review of significant literature in their recent 2010 position statement regarding screening mammography. ·
Other: I have been interested in a potpourri of other studies, from identifying biomarkers in nipple aspirate fluid, to understanding the prognostic significance of concomitant DCIS in patients with invasive cancer (a study which won the best paper award at the Central Surgical Association meeting).
Large Database/Outcomes Research:
We use a series of large databases including the National Health Interview Survey, the National Cancer Database, and in house surveys to answer important clinical and outcomes questions. In particular, we have been interested in clinical prediction modelling, diversity and health equity issues, cancer screening and survivorship issues, and cost, quality and access to care.
Prospective Therapeutic Clinical Trials:
SHAVE: A randomized controlled trial of routine shave margins vs. standard partial mastectomy
A Chemoprevention Study of Black Cohosh in Women with DCIS
PREHAB: A randomized pre-surgical window trial of mindfulness vs. exercise on biomarkers in breast cancer patients
Collaborative Translational Research:
Understanding the intersection between clinical phenotype and intratumoral heterogeneity using whole genome next-generation sequencing (with Lajos Pusztai, MD, DPhil)
Modelling Human Immune System Interaction with Breast Tumors and Treatments in Mice (with Alfred Bothwell, PhD and Joanne Sweasy, PhD)
Capsacin and eosin in local therapy for breast cancer (with John Giebel, PhD)
- Chagpar AB, McMasters KM, Sahoo S, Edwards MJ. “Does DCIS accompanying invasive carcinoma affect prognosis?”, Surgery 2009; 146(4): 567-568.
- Chagpar AB, McMasters KM, Edwards MJ. “Can sentinel node biopsy be avoided in some elderly breast cancer patients?”, Annals of Surgery 2009; 249(3): 455-460.
- Chagpar AB, Polk HC, McMasters KM. “Racial trends in mammography rates: A population-based study”, Surgery 2008; 144(3); 467-472.
- Chagpar AB, McMasters KM. “Trends in mammography and clinical breast examination: A population-based survey”, Journal of Surgical Research 2007; 140(2): 214-219.
- Chagpar AB, Scoggins CR, Martin RC, Cook EF, McCurry T, Mizuguchi N, Paris KJ, Carlson DJ, Laidley AL, El-Eid SE, McGlothin TQ, McMasters KM. “Predicting patients at low probability of requiring post-mastectomy radiation therapy”, Annals of Surgical Onco
- Chagpar AB, Scoggins CR, Martin RC, Carlson DJ, Laidley AL, El-Eid SE, McGlothin TQ, McMasters KM. “Prediction of sentinel lymph node-only disease in women with invasive breast cancer”, American Journal of Surgery 2006; 192(6): 882-887.