Tumour epidermal growth factor receptor, erbB-2 and cathepsin D in node-negative invasive breast cancer: their impact on the selection of patients for systemic adjuvant therapy.
OBJECTIVE
To determine the feasibility and the economic impact of tumour EGFR, erbB-2 and cathepsin-D measurements in women with node-negative breast cancer.


METHODS
Consecutive tumour samples received at a regional steroid receptor laboratory from patients with node-negative breast cancer were evaluated with commercially available kits to determine EGFR, erbB-2 and cathepsin-D levels.


METHODS
All node-negative patients whose tumours were submitted to the steroid receptor laboratory from November 1992 to March 1994 were included (n = 142). A control group of concurrent node-negative breast cancer patients from the London Regional Cancer Centre (LRCC) database were also evaluated to determine the representativeness of our sample.


METHODS
To determine the proportion of patients who were positive for the 3 newer prognostic factors relative to their risk of relapse.


RESULTS
We found 75 positive values in 69 patients (48.6%). We demonstrated that each factor identified a different high-risk subgroup. Epidermal growth factor receptor (EGFR) positivity (> 10 fmol/mg protein) was found in 16.3% of patients, with 19.9% of patients positive for erbB-2 (> 250 units/mg protein) and 17.3% positive for cathepsin D (> 70 pmol/mg protein). Between 10% and 23.2% more node-negative patients currently seen in a regional cancer centre could be offered systemic adjuvant chemotherapy based on a single positive new factor.


CONCLUSIONS
These tumour evaluations are straightforward using material already available in a regional steroid receptor laboratory or on tumour tissue available to pathologists. The economic impact is minimal; the 1995 cost of performing all 3 evaluations is Can$425-616 (US$304-440) per patient treated depending on the number of assays per run. Prospective clinical trials incorporating tumour EGFR, erbB-2 and cathepsin D are feasible and economically viable.
Tonkin
K S
KS
Cross Cancer Institute, Edmonton, Alta. katiaton@cancerboard.ab.ca
McKay
J W
JW
Stitt
L W
LW
Tokmakejian
S
S
Haines
D S
DS
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000191:economics / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000628:therapy; D002402:Cathepsin D / Q000032:analysis*; D017024:Chemotherapy, Adjuvant; D016009:Chi-Square Distribution; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D066246:ErbB Receptors / Q000032:analysis*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D017698:Postmenopause; D017410:Practice Guidelines as Topic; D017697:Premenopause; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors
D002402:Cathepsin D; D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone