E. Tweedie et al., BIOLOGIC CHARACTERISTICS OF BREAST-CANCER DETECTED BY MAMMOGRAPHY ANDBY PALPATION IN A SCREENING-PROGRAM - A PILOT-STUDY, Clinical and investigative medicine, 20(5), 1997, pp. 300-307
Objective: To compare the histopathologic features and expression of p
53 and c-erb B2 in the tumours detected by mammography only (clinicall
y occult tumours) and the tumours detected by a nurse examiner (clinic
ally palpable tumours). Setting: London branch of the Ontario Breast S
creening Program, which uses both clinical breast examination and mamm
ography as screening methods. Interventions: Pathologic review and imm
unohistochemical staining of all tumours detected between 1990 and 199
3. Outcome measures: Categorization of tumours by detection method and
analysis of tumour size grade, type, lymph node status and c-erb B2 a
nd p53 expression in each group. Results: From 1990 to 1993, 131 tumou
rs were detected in patients ranging in age from 50 to 85 years (media
n 63 years). Sixty-seven occult tumours and 64 palpable lesions were d
etected. The occult tumours were significantly smaller (1.34 cm v. 2.2
9 cm, p < 0.0001) than the palpable ones and included a higher proport
ion of special-type lesions and ductal carcinoma in situ (43.3% v. 10.
9%, p < 0.0001). Occult invasive carcinomas were of lower grade than p
alpable carcinomas (68.4% grade 1, 21.1% grade 2, 10.5% grade 3 v. 32.
8% grade 1, 36.1% grade 2, 31.1% grade 3, p < 0.0001). Fewer occult le
sions showed axillary nodal metastases (19.6% v. 40.6%, p = 0.02). No
statistically significant differences were found for p53 or c-erb B2 p
ositivity between the 2 groups. Conclusion: Tumours detected by differ
ent screening methods in a screening program have different pathologic
characteristics.