[Show abstract][Hide abstract] ABSTRACT: The physiology of the nonlactating human breast likely plays a key role in factors that contribute to the etiology of breast cancer and other breast conditions. Although there has been extensive research into the physiology of lactation, few reports explore the physiology of the resting mammary gland, including mechanisms by which compounds such as hormones, drugs, and potential carcinogens enter the breast ducts. The purpose of this study was to explore transport of exogenous drugs into ductal fluid in nonlactating women and determine if their concentrations in the fluid are similar to those observed in the breast milk of lactating women. We selected two compounds that have been well characterized during lactation, caffeine and cimetidine. Caffeine passively diffuses into breast milk, but cimetidine is actively transported and concentrated in breast milk. After ingestion of caffeine and cimetidine, 14 nonlactating subjects had blood drawn and underwent ductal lavage at five time points over 12 h to measure drug levels in the fluid and blood. The concentrations of both caffeine and cimetidine in lavage fluid were substantially less than those observed in breast milk. Our results support recent evidence that the cimetidine transporter is not expressed in the nonlactating mammary gland, and highlight intriguing differences in the physiology and molecular transport of the lactating and nonlactating breast. The findings of this exploratory study warrant further exploration into the physiology of the nonlactating mammary gland to elucidate factors involved in disease initiation and progression.
Journal of physiology and biochemistry 12/2011; 67(4):621-7. DOI:10.1007/s13105-011-0109-z · 1.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ductal lavage is a technique that samples the contents of breast ducts for research into the biology of breast cancer. Enthusiasm for this method has declined because of technical challenges associated with the procedure. These include: difficulty in duct cannulation, high levels of subject discomfort, and an inability to confirm perforation.
As part of a larger institutional review board (IRB)-approved study, consenting healthy women underwent ductal lavage of 3-4 ducts in one breast. Intranipple lidocaine was administered before duct cannulation. Ductoscopy was performed prior to catheterization and high-definition ultrasound was used for imaging during the lavage procedure. Pain scores were recorded at 24 hours and 2 weeks. Subjects were asked to return in 6 months for a repeat of the procedure.
Ductoscopy was performed prior to lavage under real-time ultrasound 308 times in 107 subjects. There were 280 confirmed ducts (90.9%) and 21 perforations (6.8%), while seven (2.3%) were indeterminate. Subjects reported minimal discomfort, and 91% reported a 0 (0-10 range) pain score 2 weeks after the procedure. The retention rate was 90% at 6 months.
The injection of lidocaine directly into the nipple greatly increases the feasibility of duct cannulation and improves subject comfort. Confirmation of duct cannulation and lavage can be documented with ductoscopy and ultrasound imaging. These procedures can be added to ductal lavage to facilitate its use as a research tool.