Persistence of bone marrow micrometastases in patients receiving adjuvant therapy for breast cancer: Results at 4 years

Abstract

We have previously developed a quantitative PCR (QPCR) technique for the detection of cytokeratin 19 (CK19) transcripts in blood and bone marrow and compared this to immunocytochemistry (ICC).Together, both have shown promise for monitoring therapeutic efficacy in patients with metastatic breast cancer. The aim of this study was to determine the feasibility and value of these assays for minimal residual disease (MRD) in monitoring efficacy of adjuvant therapy following surgery for primary breast cancer. Bone marrow aspirates and peripheral blood samples were taken at the time of surgery from patients with primary breast cancer and no evidence of metastases on conventional scans. These were tested for the presence of CK19 mRNA transcripts and cytokeratin positive cells. Follow-up bone marrow aspirates were taken at 3, 6, 12, 24, 36 and 48 months. Prior to surgery, 51% of patients displayed evidence of disseminated cancer cells in the bone marrow by either or both QPCR and ICC. Of 91 patients who had repeat samples assayed, 87% and 65% had positive results at some time using QPCR and ICC, respectively. All patients received adjuvant systemic therapy and in 44 cases where there was a positive result in either the pretreatment or 3-month aspirate, 32/44 (73%) showed a fall in CK19:ABL ratio (QPCR) and 15/24 (63%) showed a reduction in the number of cytokeratin-positive cells (ICC) during follow-up. These results indicate that MRD persists despite adjuvant therapy in a majority of patients with primary breast cancer up to 4 years following surgery.

Comparison of bone marrow, disseminated tumour cells and blood-circulating tumour cells in breast cancer patients after primary treatment

“…We have previously published the fact that there is occasional evidence of DTCs on follow-up of patients over 4 years after treatment for primary breast cancer (Slade et al, 2005). Most patients show considerable variability.…”

“…To have a group of patients who were at very low risk of having recurrence in the future, we decided to take the subset of patients from our published study (Slade et al, 2005) to include only those patients with T 1 N 0 (i.e., those who had a tumour p2 cm)and who were node negative (group II) 4 -13 years post-surgery. For the high-risk group (group III), we included patients who previously had 43 node-positive breast cancer (with one exception, a patient with two positive nodes) and were on follow-up and who had no sign or symptom of recurrence.…”

“…On account of the difficulties inherent in subjecting patients to regular bone marrows, as well as the small number of cells detected in primary patients with no evidence of overt metastases, such tests have been difficult to apply in routine clinical practice. Furthermore, until recently, the peripheral blood has been shown to be generally negative for CTCs in all but a minority of patients, with most series showing 1 -5% of patients found to be positive (Schoenfeld et al, 1997;Slade et al, 2005).…”

Impact of cyclins E, neutrophil elastase and proteinase 3 expression levels on clinical outcome in primary breast cancer patients

“…All samples were normalized for ABL gene expression, which has been reported in several breast cancer papers as reference gene to normalize RT-PCR data. [20][21][22][23] The ABL forward primer was 5 0 -CGTCCTCCAGCTGTTATCTGG-3 0 and reverse primer was 5 0 -CACTCAGACCCTGAGGCTCAA-3 0 . All primers were designed with Primer Express Software.…”

Predicted trends in long-term breast cancer survival in England and Wales

“…Where long-term survival has been examined, it has mostly been shown that women with breast cancer continue to experience excess mortality into the second and third decades after their diagnosis (Duncan and Kerr, 1976;Langlands et al, 1979;Brinkley and Haybittle, 1984;Adami et al, 1986;Zahl and Tretli, 1997;Joensuu et al, 1999). This excess mortality may be due to the existence of 'micro-metastases' -disseminated cancer cells present even in women with apparently localised disease at diagnosis (Slade et al, 2005). Because previous survival studies have been based on cohort or complete approaches, trends in longterm survival have involved women diagnosed from the 1940s up to the 1970s, at least 10 years before the important advances in diagnosis and management that occurred during the 1980s.…”