title: Benefit of ultrasonography in the detection of clinically and mammographically occult breast cancer.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the performance of high-resolution ultrasonography in the detection of clinically and mammographically occult breast cancer.
  
  
  METHODS
  From September 2003 to November 2006, a total of 1485 patients were confirmed to have in situ or invasive breast cancer in Hong Kong Sanatorium and Hospital Breast Care Centre. All patients underwent mammography (MMG) and/ or sonography (USG) evaluation. Patients' age and size of tumor detected by USG alone were compared with those detected by MMG.
  
  
  RESULTS
  Altogether, 222 patients (17%) had positive imaging findings on USG only, among which 22 (13%) patients had nonpalpable tumors. Performing USG increased the cancer detection rate among clinically and mammographically occult breast lesions by 14.3%. The mean size of the tumors detected only by USG was 1.98 cm, which was not significantly different from the mean size of tumor detected by MMG (1.46) (p = 0.23). This remains true in the group of patients with nonpalpable tumors (1.36 vs. 1.46 cm, p = 0.88). The sensitivity of USG is 91%, which is significantly higher than that of MMG (78%) (p = 0.001). This remains true in patients age <40 or > or = 40, tumor grading I toIII, and LVI +/- cases. However, MMG had higher sensitivity in the group of patients with nonpalpable tumors (73% vs. 62%, p = 0.01) and noninvasive cancers (72% vs. 69%, p = 0.01).
  
  
  CONCLUSIONS
  The use of high-resolution USG may lead to detection of a significant number of occult cancers that are no different in size from nonpalpable mammographically detected lesions.
authors.affiliation: Department of Surgery, United Christian Hospital, Hong Kong, Republic of China.
authors.forename: Sharon W W
authors.initials: SW
authors.lastname: Chan
authors.forename: Polly S Y
authors.initials: PS
authors.lastname: Cheung
authors.forename: Stefanie
authors.initials: S
authors.lastname: Chan
authors.forename: Suk Sze
authors.initials: SS
authors.lastname: Lau
authors.forename: Ting Ting
authors.initials: TT
authors.lastname: Wong
authors.forename: Michael
authors.initials: M
authors.lastname: Ma
authors.forename: Ada
authors.initials: A
authors.lastname: Wong
authors.forename: Yuen Ching
authors.initials: YC
authors.lastname: Law
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016462:Mammaplasty; D008327:Mammography; D008408:Mastectomy; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D016217:Ultrasonography, Mammary; D055815:Young Adult