Acta med. scand. Vol. 197, pp. 367-375, 1975
SERUM CALCITONIN RESPONSE TO INDUCED HYPERCALCEMIA A Diagnostic Aid in Eurly Occult Medullary Thyroid Carcinoma Margareta Telenius-Berg, Sven Almqvist and Birgitta Wasthed From the Depurtments of Internul Medicine, University Hospital, Lund, and University Hospitul, Linkoping, Sweden
Abstract. The rise in serum calcitonin (A-CTllo d,,)has been measured during hypercalcemia induced by i.v. infusion of calcium gluconate. This calcium infusion test was used in a prospective screening for medullary carcinoma of the thyroid (MCT) in 4 families with Sipple’s syndrome as well as in 3 sporadic cases of MCT. In 16 normal controls A-CT,, was -0.2-+0.5 ng/ml (mean _+2 S.D.). A-CTZ4,, was normal in 2 patients with chronic hypocalcemia. In all 14 MCT patients A-CT,, was markedly higher (min-max 2.2-630 nglml), i.e. no false negatives were found. However, in these cases, the diagnosis was already evident from basal serum calcitonin (S-CT), which up to now has been our most sensitive diagnostic technique for MCT. 19 firstdegree relatives of patients with Sipple’s syndrome presented no signs of MCT. In 14 of these A-CTuo was normal (“healthy relatives”), but in 5 it was slightly elevated, intermediate between the controls and the MCT patients. These 5 borderline cases were more sharply delineated from normal by A-CTllo than by S-CT. Thus our calcium infusion test seems to be the most sensitive method for car/y diagnosis of occult MCT. We recommend the calcium infusion test for: ( a ) screening for MCT in all Sipple relatives with normal or only slightly elevated basal S-CT, (b) postoperative control in both sporadic and hereditary MCT, (c) investigation of supposed non-MCT tumours with calcitonin production.
Determination of basal serum calcitonin (S-CT) with
a specific and sensitive radioimmunoassay is very useful in the diagnosis of medullary carcinoma of the thyroid (MCT) ( I , 4, 17). It is superior t o conventional methods (clinical examination and thyroid scintiscan), fine needle biopsy (25) and determination of serum diamine oxidase activity (histamindse, E.C. 1.4.3.6.)(27). Both in normal human C cells and in medullary carcinoma cells, calcitonin (CT) secretion is stimulated by hypercalcemia (17,23). In patients with very small tumours, the basal level of S-CT may be normal or close to the upper
normal limit, e.g. in early cases andafter non-radical surgery. In these patients determination of the S-CT response to induced hypercalcemia might provide us with a n even more sensitive method, that would disclose occult, i.e. asymptomatic tumours. The purpose of this investigation was to evaluate this hypothesis. MA TERIA L The patient material comprised three cases of sporadic MCT (S: 1-3) and 30 members of four separate families (families I-IV) with Sipple’s syndrome. This is a hereditary syndrome with MCT usually combined with bilateral pheochromocytomas (21, 27), which is transmitted as an autosomal dominant trait. The Sipple families were screened prospectively for these hereditary tumours. Our screening program for MCT includes 1) careful clinical examination, 2) thyroid scintiscan using Ia1I and/or 8emTc,3) tine needle aspiration biopsy of all palpable thyroid nodules and/or lymph nodes of the neck, 4) determination of serum diamine oxidase activity (histaminase, E.C. 1.4.3.6.)and 5) determination of S-CT, using our radioimmunoassay method for human S-CT (1). both ( a ) basal level and (b) the response to induced hypercalcemia, which is the subject of this report. This screening program revealed 8 new cases of MCT (patients I: 1-3, Ikl-3, 111: 1-2). All Sipple patients except one (II:2) as well as the sporadic cases (Table I) had their MCT diagnosis verified by surgery and histopathology using the criteria of Hazard et al. (1 I ) and Williams et al. (30). Patient II:2 refused surgery, but his Sipple’s syndrome was regarded as indirectly verified as he was a genetically proved camer of the Sipple genome. He also had a raised basal S-CT as well as bilateral pheochromocytomas, verified by adrenal angiography and high urine excretion of VMA and catecholamines. Three Sipple patients (111:3-5), earlier operated upon for MCT, were examined for occult metastases. They had no clinical signs of recurrence. Six patients were examined both before and after surgery for MCT (Table 11). Controls. Sixteen healthy volunteers of either sex, aged 15-60 years, without clinical or laboratory signs of disActa med. scand. 197
368
M. Telenius-Berg et al.
Table I. S-CT response to calcium infusion (ACTt) in 14 patients with MCT Pat. no. I: 1 1:2 1:3 11: I II:2 II:3 111:1 III:2 IIk3" III:4" 1115" s:1 s:2
s:3
Sex
s P 0
s
6 8
6 9
P 6
s s 9
P
Upper reference limit (nglml) a
Age (y.)
S-CT atO'
A-CT,
A-CTuo
57 54 22 58 59 33 21 21
21.3 5.1 2.1 5.2 2.4 4.9 2.0 2.1 2.5 3.4 5.1 13.4 980 6.1 1.6 1.04
10.9 1.7 0.7 5.6 1.4 4.4 3.1 1.0 3.2 1.8 3.2 0.6 250 4.9 0.9 0.43
4.2 2.2 9.5 4.2 14.4 7.5 1.4 8.2 12.9 4.4 10.6 630 12.1 13.4 0.50
48 57 55 71 78 67
Earlier operated on for MCT
ordered thyroid or calcium metabolism served as controls. Furthermore we examined two women (patients H: I and H:2) with long-standing hypocalcemia due to intestinal malabsorption. Patient H:l was 47 years old, had an intestinal radiation injury after radiotherapy against a carcinoma of the ovary and had been treated with vitamin D, although insufficiently.Patient H:2 was 34 years old and probably had a gluten-sensitive enteropathy. Both had serum calcium (S-Ca) levels around 3.6-3.9 mEq/l (Table 111).
METHODS Serum calcitonin. The radioimmunoassay technique has been described in detail in a previous paper (1). S-CT levels are expressed as nglml. Reference values 0.36-1.04 nglml. Serum calcium.S-Ca was determined by flame emission photometry. Calcium irlfusion rest. Transient hypercalcemia was induced by infusing 3.75 mmol=7.5 mEq-15 mg Ca++/kg b.wt. as calcium gluconate in loo0 ml 10% invertose solution during 4 hours. All subjects were normocalcemic before the infusion and had normal renal function. All except patient II:2 were fasting. The infusion induced a rise in S-Ca of 1.43f2X0.56 mEq/l (mean +2 S.D.). At the end of the infusion S-Ca was 6.25k2x0.44 mEq/l (mean +2 S.D.). MCT patients did not differ from the controls in this respect. S-CT was analysed in peripheral venous blood taken at 0', 60' and 240'. S-CT at 0' is the arithmetic mean of two separate samples taken at -5' and just before the start of the infusion. Zero time (0') is the start of the infusion, usually at about 10 a.m. In seven patients additional samples were taken at 30', !", 120' and 180'. The expression "normal range" for A-CTzao=meanf 2 S.D. of healthy controls. The S-CT rise during induced hypercalcemia at t min after the start, zero time, is denoted A-CTt. A d a med. scand. 197
RESULTS Healthy controls In the 16 healthy controls A-CTzrowas small, normal range -0.2-+0.5 ng/ml (mean +2 S.D.=0.14+ 2 xO.18 ng/ml, p
SERUM CALCITONIN RESPONSE TO INDUCED HYPERCALCEMIA A Diagnostic Aid in Eurly Occult Medullary Thyroid Carcinoma Margareta Telenius-Berg, Sven Almqvist and Birgitta Wasthed From the Depurtments of Internul Medicine, University Hospital, Lund, and University Hospitul, Linkoping, Sweden
Abstract. The rise in serum calcitonin (A-CTllo d,,)has been measured during hypercalcemia induced by i.v. infusion of calcium gluconate. This calcium infusion test was used in a prospective screening for medullary carcinoma of the thyroid (MCT) in 4 families with Sipple’s syndrome as well as in 3 sporadic cases of MCT. In 16 normal controls A-CT,, was -0.2-+0.5 ng/ml (mean _+2 S.D.). A-CTZ4,, was normal in 2 patients with chronic hypocalcemia. In all 14 MCT patients A-CT,, was markedly higher (min-max 2.2-630 nglml), i.e. no false negatives were found. However, in these cases, the diagnosis was already evident from basal serum calcitonin (S-CT), which up to now has been our most sensitive diagnostic technique for MCT. 19 firstdegree relatives of patients with Sipple’s syndrome presented no signs of MCT. In 14 of these A-CTuo was normal (“healthy relatives”), but in 5 it was slightly elevated, intermediate between the controls and the MCT patients. These 5 borderline cases were more sharply delineated from normal by A-CTllo than by S-CT. Thus our calcium infusion test seems to be the most sensitive method for car/y diagnosis of occult MCT. We recommend the calcium infusion test for: ( a ) screening for MCT in all Sipple relatives with normal or only slightly elevated basal S-CT, (b) postoperative control in both sporadic and hereditary MCT, (c) investigation of supposed non-MCT tumours with calcitonin production.
Determination of basal serum calcitonin (S-CT) with
a specific and sensitive radioimmunoassay is very useful in the diagnosis of medullary carcinoma of the thyroid (MCT) ( I , 4, 17). It is superior t o conventional methods (clinical examination and thyroid scintiscan), fine needle biopsy (25) and determination of serum diamine oxidase activity (histamindse, E.C. 1.4.3.6.)(27). Both in normal human C cells and in medullary carcinoma cells, calcitonin (CT) secretion is stimulated by hypercalcemia (17,23). In patients with very small tumours, the basal level of S-CT may be normal or close to the upper
normal limit, e.g. in early cases andafter non-radical surgery. In these patients determination of the S-CT response to induced hypercalcemia might provide us with a n even more sensitive method, that would disclose occult, i.e. asymptomatic tumours. The purpose of this investigation was to evaluate this hypothesis. MA TERIA L The patient material comprised three cases of sporadic MCT (S: 1-3) and 30 members of four separate families (families I-IV) with Sipple’s syndrome. This is a hereditary syndrome with MCT usually combined with bilateral pheochromocytomas (21, 27), which is transmitted as an autosomal dominant trait. The Sipple families were screened prospectively for these hereditary tumours. Our screening program for MCT includes 1) careful clinical examination, 2) thyroid scintiscan using Ia1I and/or 8emTc,3) tine needle aspiration biopsy of all palpable thyroid nodules and/or lymph nodes of the neck, 4) determination of serum diamine oxidase activity (histaminase, E.C. 1.4.3.6.)and 5) determination of S-CT, using our radioimmunoassay method for human S-CT (1). both ( a ) basal level and (b) the response to induced hypercalcemia, which is the subject of this report. This screening program revealed 8 new cases of MCT (patients I: 1-3, Ikl-3, 111: 1-2). All Sipple patients except one (II:2) as well as the sporadic cases (Table I) had their MCT diagnosis verified by surgery and histopathology using the criteria of Hazard et al. (1 I ) and Williams et al. (30). Patient II:2 refused surgery, but his Sipple’s syndrome was regarded as indirectly verified as he was a genetically proved camer of the Sipple genome. He also had a raised basal S-CT as well as bilateral pheochromocytomas, verified by adrenal angiography and high urine excretion of VMA and catecholamines. Three Sipple patients (111:3-5), earlier operated upon for MCT, were examined for occult metastases. They had no clinical signs of recurrence. Six patients were examined both before and after surgery for MCT (Table 11). Controls. Sixteen healthy volunteers of either sex, aged 15-60 years, without clinical or laboratory signs of disActa med. scand. 197
368
M. Telenius-Berg et al.
Table I. S-CT response to calcium infusion (ACTt) in 14 patients with MCT Pat. no. I: 1 1:2 1:3 11: I II:2 II:3 111:1 III:2 IIk3" III:4" 1115" s:1 s:2
s:3
Sex
s P 0
s
6 8
6 9
P 6
s s 9
P
Upper reference limit (nglml) a
Age (y.)
S-CT atO'
A-CT,
A-CTuo
57 54 22 58 59 33 21 21
21.3 5.1 2.1 5.2 2.4 4.9 2.0 2.1 2.5 3.4 5.1 13.4 980 6.1 1.6 1.04
10.9 1.7 0.7 5.6 1.4 4.4 3.1 1.0 3.2 1.8 3.2 0.6 250 4.9 0.9 0.43
4.2 2.2 9.5 4.2 14.4 7.5 1.4 8.2 12.9 4.4 10.6 630 12.1 13.4 0.50
48 57 55 71 78 67
Earlier operated on for MCT
ordered thyroid or calcium metabolism served as controls. Furthermore we examined two women (patients H: I and H:2) with long-standing hypocalcemia due to intestinal malabsorption. Patient H:l was 47 years old, had an intestinal radiation injury after radiotherapy against a carcinoma of the ovary and had been treated with vitamin D, although insufficiently.Patient H:2 was 34 years old and probably had a gluten-sensitive enteropathy. Both had serum calcium (S-Ca) levels around 3.6-3.9 mEq/l (Table 111).
METHODS Serum calcitonin. The radioimmunoassay technique has been described in detail in a previous paper (1). S-CT levels are expressed as nglml. Reference values 0.36-1.04 nglml. Serum calcium.S-Ca was determined by flame emission photometry. Calcium irlfusion rest. Transient hypercalcemia was induced by infusing 3.75 mmol=7.5 mEq-15 mg Ca++/kg b.wt. as calcium gluconate in loo0 ml 10% invertose solution during 4 hours. All subjects were normocalcemic before the infusion and had normal renal function. All except patient II:2 were fasting. The infusion induced a rise in S-Ca of 1.43f2X0.56 mEq/l (mean +2 S.D.). At the end of the infusion S-Ca was 6.25k2x0.44 mEq/l (mean +2 S.D.). MCT patients did not differ from the controls in this respect. S-CT was analysed in peripheral venous blood taken at 0', 60' and 240'. S-CT at 0' is the arithmetic mean of two separate samples taken at -5' and just before the start of the infusion. Zero time (0') is the start of the infusion, usually at about 10 a.m. In seven patients additional samples were taken at 30', !", 120' and 180'. The expression "normal range" for A-CTzao=meanf 2 S.D. of healthy controls. The S-CT rise during induced hypercalcemia at t min after the start, zero time, is denoted A-CTt. A d a med. scand. 197
RESULTS Healthy controls In the 16 healthy controls A-CTzrowas small, normal range -0.2-+0.5 ng/ml (mean +2 S.D.=0.14+ 2 xO.18 ng/ml, p
