Abstracts 61

Upper limit of normal

Normal Decrease Stable Increase limits (-> 10%) (?< 10%) (+> 10%)

CEA 6ng/ml 0 -2 +l +2 CA15-3 33 U/ml 0 -2 +l +2 ESR 20mrn/h 0 -1 +l +2

Scores for each individual marker were added together to give the response index score.

In 65 patients with systemic breast cancer changes in these three markers at 2,4 and 6 months showed a highly significant correlation with UICC assessed response at 6 months. At 4 months, changes in these three markers resulted in a selectivity of 93% with a sensitivity of 92% and a specificity of 82%. Survival of groups of patients assessed biochemically or by UICC criteria for non-progression or progression showed no significant difference.

The use of three markers increased the sensitivity of the biochemical assessment to 93% compared to 70% for CA&3 alone.

The advantages of biochemical assessment are that it is objective and reproducible. The assessment gives similar infor- mation to the UICC assessment but can be carried out earlier. Changes in the three markers appear to reflect the dynamics of change in tumour mass in response to systemic therapy in contrast to the UICC criteria which reflect structural change.

11 The Nottingham biochemical index (ESR, CEA, CA 15.3): a marker of therapeutic response in metastatic breast cancer and its potential role in rationalising breast cancer therapy

A. R. Dixon

City Hospital, Nottingham, UK

A biochemical (ESR, CEA, CA 15.3) response index (NBI) was prospectively evaluated in 163 patients treated by 1st (62) and 2nd line (47) hormone therapy and cytotoxic chemotherapy (67); 156 patients were UICC and biochemically assessable. Marker changes at 2 months correlated with the UICC assessed response at 6 months (< 0.00) for all three individual treatment groups. In the combined group the NBI had a sensitivity 83%, specificity 83%; PPV 74%; NPV 89%. There was no difference in survival between responders and progressors as assessed by the two methods.

The index has been prospectively evaluated in directing chemotherapy. A selected group of 26 responding (biochemi- cal/clinical) patients were randomised to discontinue cytotoxics after 6 months and move to maintenance hormones (n = 13) or to continue chemotherapy whilst the biochemical markers kept falling or remained within the normal range; biochemical progression prompted a change of chemotherapy. Continuous chemotherapy in biochemically selected responders was asso- ciated with a significant lengthening of remission duration (21 vs 12 months, p = O.OO), an improved quality of life (p = 0.03) and survival (27 vs 17 months; p = 0.04). We now use the index to routinely direct chemotherapy and select out true responders for maintenance therapy.

The index was finally prospectively evaluated in directing primary systemic therapies. 60 newly diagnosed patients were randomized to have treatment guided by tumour markers alone (30) or conventional means (UICC). Clinical evidence of disease progression was significantly delayed in the marker directed group (18 months vs 10); marker evidence of progres- sion having occurred at 7 months (p = 0.03) allowing an early and successful change of therapy. Quality of life scores were improved in the marker directed group and there was a trend towards an improved survival. Marker directed therapy was

also associated with fiscal savings. Marker direction provides a quick, reliable, cost-effective objective measure of early therapeutic response in metastatic breast cancer and can be used for both hormonal and cytotoxic chemotherapy.

12 Assessment of response in bone metastases from breast cancer

R. Coleman

Senior Lecturer & Honorary Consultant Medical Oncologist, YCRC Department of Clinical Oncology, Weston Park Hospital, Shefield, UK

Bone is the most common site to be involved by metastatic spread from breast cancer and the majority of women with advanced breast cancer will at some time require palliative treatment for the complications of skeletal disease. External beam radiotherapy, radioisotope pharmaceuticals, endocrine agents, chemotherapy and bisphosphonates are all valuable treatment modalities. However, assessing response to therapy in bone is very difficult. The UICC criteria rely on serial radio- graphic changes which at best, are an indirect slowly evolving reflection of tumour activity. In many patients the presence of sclerotic metastases and mixed lytic and sclerotic lesions com- plicates interpretation further.

Alternatives to plain radiographs for response assessment are urgently needed. Suggested techniques include imaging tests, measures of subjective response, tumour markers and biochemical monitoring of bone metabolism. At present, de- spite the rapid improvements in imaging, a radiological altema- tive to plain radiography has not been established. Serial bone scans give conflicting results due to confusion between the healing response and increased osteoblast activity from pro- gressive disease. Computerized tomography is only appropriate for following target lesions, while serial magnetic resonance imaging and bone mineral density measures are yet to be criti- cally evaluated. Pain relief is clearly a principle aim of pallia- tive therapy but validated reliable instruments for measuring subjective response have not been defined. However, assess- ment of subjective response should at least include changes in the severity of pain, analgesic consumption and mobility. Currently tumour markers and biochemical monitoring of bone metabolism offer the most promising, widely applicable and reproducible alternatives.

Bone metastases develop following the attraction of tumour cells circulating in the bone marrow capillaries to the endosteal bone surface. There, these cells are able to produce a variety of paracrine and humoral factors which stimulate normal bone cell activity, resulting in osteoclastic bone resorption and vari- able amounts of new bone formation. Effective systemic treat- ment for bone metastases reverses this process (at least partially) leading to a reduction in the rate of bone resorption and healing of the lytic component.

Bone is comprised of a mineralized matrix, bone cells and water. Changes in the mineral component are reflected by se- mm and urinary levels of calcium while a whole range of colla- gen fragments and crosslinking molecules have been shown to correlate with variations in the matrix. In addition other bone cell products, particularly alkaline phosphatase and osteocalcin from osteoblasts and tartrate resistant acid phosphatase from osteoclasts will reflect changes in bone metabolism.

In benign disorders of bone metabolism, biochemical moni- toring of bone cell activity is of some value in screening for disease and particularly useful for monitoring progress and response to treatment. However, relatively little work has been performed in metastatic bone disease. Acute changes (at 1 month) in urinary calcium excretion, reflecting bone resorption, and osteocalcin and alkaline phosphatase as measures of bone formation following initiation of a new systemic treatment

68 The Breast

have been shown in a relatively small study to predict radio- logical response while more recently preliminary data suggest that the new specific markers of collagen synthesis and break- down may be useful.

90% of bone matrix is composed of type-l collagen. This complex molecule is produced as procollagen. After cleavage of the C (PlCP) and N (PlNP) terminal ends of procollagen, the collagen chains are bound together in the bone matrix by the crosslinking molecules hydroxypyridinoline (HP) and hydroxylysyl-pyridinoline (LP). The procollagen fragments PlCP and possibly also PlNP are potential measures of colla- gen synthesis (bone repair) while the pyridinolines and their joining regions with collagen (l-CTP and NTX) reflect bone resorption. The assays for collagen crosslinks and fragments are rapidly becoming more specific and simpler to perform on either serum or urine samples. Critical evaluation of their value in malignancy is now indicated.

13 Osteolysis is mediated by humoral mechanisms in patients with breast cancer and bone metastases

N. J. Bundred, J. Walls and A. Howell*

Departments of Surgery and *Oncology, University Hospital of South Manchester, Manchester, UK

The aim of this prospective study was to establish the mecha- nisms leading to hypercalaemia and progression of bone metastases in patients with breast cancer, using recently identi- fied humoral and osteolytic markers.

80 women with breast cancer and newly diagnosed bone metastases were studied; (progressive n = 35, stable n = 24, responding n = 21) as determined by UICC criteria. Patients were monitored at monthly intervals, when blood and urine samples were collected. Plasma parathyroid hormone-related protein (PTHrP), the putative cause of hypercalcaemia of malignancy, and parathyroid hormone (PTH), were measured using immunoradiometric assays. In-house radioimmunoassays were used to measure serum 1,25 (OH), vitamin D, and 25(OH)D. Urinary cyclic adenosine monophosphate (CAMP), the second messenger of PTH receptor activation was meas- ured by radioimmunoassay. Three novel urinary markers of bone resorption were measured by high performance liquid chromatography; pyridinoline (Pyd), deoxypridinoline (Depyd) and galactosyl hydroxylysine (Gal Hyl).

PTHrP was undetectable in 95% of patients with stable bone metastases, and became detectable when they progressed (p < 0.05). Of 18/80 (23%) who developed hypercalcaemia, median plasma PTHrP was significantly elevated (p < 0.001). Hypercalcaemic patients had significantly increased urine CAMP excretion, compared with stable bone metastases (p < 0.02). PTHrP correlated with urine CAMP (r = 0.41, p cO.O5), and serum calcium (r = 0.45, p < 0.04). PTH became suppressed with the onset of hypercalcaemia (< 15 pg/ml, p c O.OOl), and therefore any CAMP produced was a response to renal PTHrP stimulation, suggesting a humoral mechanism of osteolysis.

In animal models of hypercalcaemia, PTHrP can stimulate vitamin D synthesis but its effect in patients with breast cancer is unclear. Women with bone metastases had reduced 1,25 (OH),D levels, which became significantly lower with the on- set of hypercalcaemia, (p < 0.001). Women with stable bone metastases, had stable levels of 1,25 (OH),D, however when they progressed a significant decrease in 1,25 (OH),D synthesis was observed (p c 0.04). Serum 1,25 (OH)*D fell when PTI-IrP increased, implying PTI-IrP does not stimulate 1,25 (OH)ID production in patients with breast cancer.

Urine Pyd excretion indicated normal bone matrix turnover in women with stable bone metastases, but was increased in hypercalcaemia, (p c 0.01). Depyd excretion was also higher in hypercalcaemia, (p < 0.05). Both Pyd and Depyd excretion increased with progression of bone metastasis (p < 0.05). Gal

Hyl excretion was also increased in hypercalcaemia compared with stable bone metastases, (p < O.Ol), and correlated with Pyd and Depyd (r = 0.56, r = 0.48 respectively). 25% of women with hypercalcaemia, however, had normal indices of bone resorption and therefore the mechanism in these cases was humoral. Finally, in 50% of hypercalcaemic women, renal tubular reabsorption of calcium was increased, indicating humorally mediated calcium reabsorption was present.

This study indicates that a substantial proportion of bone resorption in women with breast cancer is humorally mediated, and the mechanisms leading to hypercalcaemia are complex. We have demonstrated four potential novel markers for moni- toring bone metastases response.

14 Gross cystic disease fluid protein (CP-15) identifies breast cancer bone metastases response to treatment as accurately as the tumour marker CAE-3

N. J. Bundred, J. Walls and A. Howell*

Departments of Surgery and *Oncology, University Hospital of South Manchester, Manchester, UK

Gross cystic disease fluid protein- 15 (CP- 15) has been claimed to be a useful marker of disease response in breast cancer. The aim of this study was to compare CP-15 with other standard markers of tumour response in patients with breast cancer and bone metastases.

Plasma CP- 15 was measured by a 2-stage solid phase enzyme immunoassay, in women with bone metastases (responding n = 30, progressing n = 22), early breast cancer (EBC, n = 72), and locally advanced breast cancer (n = 8). Carcinoembryonic anti- gen (CEA) was measured by fluoroimmunoassay, and CA15-3 by an immunoradiometric assay.

The plasma levels of CP-15 did not differ between patients with EBC, locally advanced breast cancer, or patients with bone metastases. CP- 15 levels were significantly higher in pro- gressing bone metastases, compared to those with responding bone metastases, (p c 0.001). CP-15 levels sequentially fell when bone metastases responded to treatment, and sequentially rose when bone metastases progressed (p < 0.04, ANOVA). In patients with progressing bone metastases, 59% of CEA, 68% of CA15-3 and 77% of CP-15 levels were elevated at presenta- tion. At monthly intervals, however, median CEA levels did not change, CA-15 levels sequentially increased by a median of 32% and CP-15 by 50%.

Plasma CP-15 levels appear more sensitive than either CA15-3 or CEA in predicting response of patients with bone metastases to changes in treatment. For individual patients, changes in CP-15 levels were easier to monitor, and were greater in magnitude. Plasma CP-15 levels identify response to therapy in bone metastases patients with greater frequency and equal accuracy to the tumour marker CA15-3.

Statistics by Kruskal-Wallis analysis of variance (ANOVA) Mann-Whitney, and Chi-squared test.

15 C-erbB2 oncoprotein in the serum of patients with breast cancer

P. Willsher and J. F. R. Robertson

Department of Surgery, City Hospital, Nottingham, UK

C-erbB2 DNA amplification has been shown to correlate with decreased survival in breast cancer patients. Tissue detection of the c-erbB2 protein has been assessed in a number of studies. However, investigation of the significance of serum c-erbB2 protein is limited.

We have studied sera from normal individuals (24), patients