Journal of Surgical Oncology 44: 1 4 ( 1990)
Neuron-Specific Enolase During Chemotherapy of Small Cell Lung Cancer P.K. BL‘AMAH,
MO,
S.R. DRAKE,
t1.M. SMEDLEY, rKcK, W.A.H. BODC;ER, A.W. SKILLEN, f’hl)
FK(.K,
AND
TK(-K,
From the Unit for C‘ancxv Studies arid Departnicnt oi Clinic-dl Biochemistry, Thanet District CcncrdI flospital, Margatfi, Kent, England fP.K.B., S . K . D . ) ; Department of Kadiothcrapy, Kent md Canlerhry Ho,prfa/, C d f i l C r b U r y , Kent, Lng/anc/ II-i.M.S., W.A.f i.8.j; Dfykwtmcnl of Clinical Bioc:hfmistry, The Medicdl School, N c w c a d c Lipon Tync, t n g h i d ( A .W.5.J
Serum neuron-specific enolase (NSE) has been measured in 28 patients with small cell lung cancer (SCLC) and 90 patients with other forms of lung cancer (NSCLC), i.e.. 28 with adenocarcinoma and 62 with squamous cell carcinoma. Increased NSE ( >12.0 pgAiter) was found in 71.4% of SCLC patients and in 22.2% of NSCLC patients. The predictive value of an increased NSE in identifying SCLC was only 50%, whereas the predictive value of a normal NSE in differentiating SCLC for NSCLC was 91%. Serial studies during chemotherapy of SCLC patients showed that the doubling time of NSE ranged from 7 to 127 days and the mean apparent half-life (AHL) of NSE to be 14 days. AHL values in excess of 20 days suggest that the tumour is not in full remission. We believe that measurement of serum NSE and calculation of the AHL and DT are valuable in identifying the effectiveness of chemotherapy in patients with SCLC. KEY WORDS: apparent half-life, doubling time, adenocarcinoma, squamous cell carcinoma
INTRODUCTION Enolases (EC 4.2.1. I 1 .) are glycolytic enzymes that catalyse the conversion of 2-phospho-glycerate to phospho-enolpyruvate. Brain and neuroendocrine tissues contain dinieric forms of enolases, acy and yy. respectively. A hybrid for ( a y )is also present in these tissues. A third form of enolase Cpp) is also present in muscle cells. In the brain, the aa-enolase is confined to plial cells, whereas the yy forin is neuronal in origin. Separation of the neuron-specific enolase (NSE) and nonneuronal enolase can be achieved by electrophoresis using cellulose acetate I 11 or other methods. e.g., radioimmunoassay (RIA). In malignancy there is often a shift in the isoenzyme pattern towards the yy NSE form. Using immunocytochemical techniques, NSE has been detected in most tumours of neuroectodermal or neuroendocrine origin, including neuroblastoma and small cell carcinoma of the lung. Elevated concentrations of NSE have been found in sera from patients with neuroblastoma, small :c)
l Y Y 0 Wiley-Liss, Inc.
cell lung cancer, melanoma, pancreatic islet cell carcinoma. and hypernephroma 12-61, Small cell carcinoma of the lung accounts for about 20% of lung cancers [71. This type of cancer is sensitive to radiotherapy and combination chemotherapy, leading to improved survival time, and complete cure has been documented [8]. A correct diagnosis of the tuniour ccll type is therefore esscntial, and a serum marker that would help to identify cases of small cell lung cancer and could be used for monitoring the efficacy of chemotherapy would be valuable. We have measured serum NSE concentrations in patients with small cell carcinomas of the lung, patients with adenocarcinoma of the lung, and patients with squamous cell carcinoma of the lung. The
Accepted tor publication January 2 . 1990. Address reprint requests t o Dr. P.K. Buamah, Unit for Cancer Studies and Department of Clinical Biochemistry, Thanct District General Hospital. St. Peter’s Road. Margate. Kent C T 9 4 A N . Eneland.
2
Buamah et al.
TABLE I. Summary of the Clinical Details of Patients With Small Cell Lung Cancer Case
Age (years)
I. 2.
Stage of disease
Initial NSE (cone. pgiliter)
Survival time (months)
65 51
26.0 45.9
11.0
3.
75
18.5
4.
61
9.0
5.
60
26.0
3.0
Cyclophosphamide, adriamycin, etoposide (4)
None
6.
56
11.2
25.0
Cyclophosphamide, adriamycin. etoposide (6)
5 MeV to chest 30 Gy in 12 days
7. 8. 9.
15
11.8
8.0
Cyclophosphamide. adriamycin, etoposide (3)
None
64 63
2.0
T,N,M,
19.9 14.7
13.0
Cyclophosphamide, adriamycin. etoposide (2) Methotrexate, ifosfamide, mesna (6)
None None
10.
53
TxNxM,
27.4
6.0
1 . Cyclophosphamide, adriamycin, and etoposide (3) 2. Ifosfamide and mesna (2)
None
I I.
68
T2NXMX
23.2
12.0
1. Cyclophosphamide, adriamycin, and etoposide (4) 2. Methotrexate (2)
None
12.
57
T,N,,M,
65.4
6.0
Cyclophosphamide, adriamycin, etoposide (4)
None None None
T2NxM,
Chemotherapy"
Radiotherapy
Cyclophosphamide adriamycin etoposide (4) 1 . Adrianiycin, ifosfamide. with tnesna (2) 2. Cisplatin, etoposide (2) 3. Cisplatin, ifosfamide I 1)
5 MeV to chest 5 MeV to chest 32 Gy in 24 days
18.0
1 , Cyclophosphamide, adriamycin, and etoposide (6) 2. Cisplatin, ifosfamide (3)
None
22.0
Etoposide (3) Ifodamide with mesna (3)
Co"" to chest 30 Gy in 14 days
7.0
13.
69
T,N,M,
12.9
6.0
Cyclophosphamide, adriamycin. etoposide (4)
14.
78
T,N,M,
7.3
13.0
15.
63
T,N,M,
5.3
23.0
Cyclophosphamide, vincristine, etoposide (4) Cyclophosphamide, adriamycin, etoposide (6)
16.
59
Liver metastases
132.2
12.0
1. Cyclophosphamide, adriamycin and etoposide (4) 2. 5 flurouracil, epirubicin, ifosfamide. with mesna (5)
5 MeV to chest 36 Gy in 21 days None
"Parentheses show number of courses administered
patients with small cell lung cancer were all receiving intravenous cytotoxic chemotherapy, and we assessed the serum enzyme concentrations in relation to the clinical assessment of the progress of the disease.
PATIENTS AND METHOD Twenty-eight patients with a histologically proven diagnosis of small cell lung cancer (SCLC), 28 patients with adenocarcinoma, and 62 patients with squamous cell carcinoma of the lung had blood collected for NSE estimation. Sixteen patients with SCLC (1 1 limited disease, five extensive disease) were monitored during subsequent chemotherapy. All patients received cyclophosphamide (100 mg mP2) adriamycin (50 mg m-2) and etoposide (75 mg m-2) on consecutive days, this cycle being repeated two to six times at 3-4 weekly intervals. Additional chemotherapeutic agents employed are shown in Table I. Formal assessment and restaging were made by repeated clinical, radiological, and bronchoscopic examinations. Blood samples for measurement of NSE concentration were obtained before chemotherapy and at regular intervals during the period of treatment. Samples were cen-
trifuged immediately on arrival in the laboratory, and the separated serum was frozen at -20°C until analysed. The NSE was measured using a double-antibody RIA kit from Pharmacia A.B. (Uppsala, Sweden). The assay has a dynamic range of 2-200 pg/liter and a between-batch coefficient of variation of 8%.
RESULTS The serum NSE concentrations of all 118 patients with lung cancer are summarised graphically in Figure 1. Employing an upper limit for healthy controls of 12.0 pg/ liter, which is in use in the author's laboratory, 20 of the 28 (71.4%) patients with SCLC had values greater than 12.0 pgiliter, and 13 of these (46.2%) had values greater than 25.0 pgiliter. By comparison, 22.2% of 90 patients with large cell lung cancer, i.e., 21.4% of 28 patients with adenocarcinoma and 22.5% of 62 patients with squamous cell carcinoma, had values > 12.0 pg/liter. Applying a cut-off of 25 pg/liter rather than 12 pglliter, then 46.2% of all cases of SCLC had a raised NSE level, in contrast to only 6.6% of those with other types of lung cancer (NSCLC). From these data, the predictive value of an NSE of > 12 pg/liter in differentiating SCLC from
220
180
..
140
N S E 100 Pg/L
80 60
40
. .. 0
20
C
.
t
. .
Small cell lung Adenocarcinoma cancer n = 28 n = 26
..
Squarnous cell carcinoma n = 62
Fig. 1 . Serum NSE concentration in patients with lung cancer. n. Number of patients.
NSCLC is only 50%, whereas the predictive value of an NSE of < 12 pgiliter in excluding SCLC is 91%. However, whereas the predictive value of an NSE of >25 pg/liter in identifying SCLC is increased to 68%, the predictive value of an NSE of
Neuron-Specific Enolase During Chemotherapy of Small Cell Lung Cancer P.K. BL‘AMAH,
MO,
S.R. DRAKE,
t1.M. SMEDLEY, rKcK, W.A.H. BODC;ER, A.W. SKILLEN, f’hl)
FK(.K,
AND
TK(-K,
From the Unit for C‘ancxv Studies arid Departnicnt oi Clinic-dl Biochemistry, Thanet District CcncrdI flospital, Margatfi, Kent, England fP.K.B., S . K . D . ) ; Department of Kadiothcrapy, Kent md Canlerhry Ho,prfa/, C d f i l C r b U r y , Kent, Lng/anc/ II-i.M.S., W.A.f i.8.j; Dfykwtmcnl of Clinical Bioc:hfmistry, The Medicdl School, N c w c a d c Lipon Tync, t n g h i d ( A .W.5.J
Serum neuron-specific enolase (NSE) has been measured in 28 patients with small cell lung cancer (SCLC) and 90 patients with other forms of lung cancer (NSCLC), i.e.. 28 with adenocarcinoma and 62 with squamous cell carcinoma. Increased NSE ( >12.0 pgAiter) was found in 71.4% of SCLC patients and in 22.2% of NSCLC patients. The predictive value of an increased NSE in identifying SCLC was only 50%, whereas the predictive value of a normal NSE in differentiating SCLC for NSCLC was 91%. Serial studies during chemotherapy of SCLC patients showed that the doubling time of NSE ranged from 7 to 127 days and the mean apparent half-life (AHL) of NSE to be 14 days. AHL values in excess of 20 days suggest that the tumour is not in full remission. We believe that measurement of serum NSE and calculation of the AHL and DT are valuable in identifying the effectiveness of chemotherapy in patients with SCLC. KEY WORDS: apparent half-life, doubling time, adenocarcinoma, squamous cell carcinoma
INTRODUCTION Enolases (EC 4.2.1. I 1 .) are glycolytic enzymes that catalyse the conversion of 2-phospho-glycerate to phospho-enolpyruvate. Brain and neuroendocrine tissues contain dinieric forms of enolases, acy and yy. respectively. A hybrid for ( a y )is also present in these tissues. A third form of enolase Cpp) is also present in muscle cells. In the brain, the aa-enolase is confined to plial cells, whereas the yy forin is neuronal in origin. Separation of the neuron-specific enolase (NSE) and nonneuronal enolase can be achieved by electrophoresis using cellulose acetate I 11 or other methods. e.g., radioimmunoassay (RIA). In malignancy there is often a shift in the isoenzyme pattern towards the yy NSE form. Using immunocytochemical techniques, NSE has been detected in most tumours of neuroectodermal or neuroendocrine origin, including neuroblastoma and small cell carcinoma of the lung. Elevated concentrations of NSE have been found in sera from patients with neuroblastoma, small :c)
l Y Y 0 Wiley-Liss, Inc.
cell lung cancer, melanoma, pancreatic islet cell carcinoma. and hypernephroma 12-61, Small cell carcinoma of the lung accounts for about 20% of lung cancers [71. This type of cancer is sensitive to radiotherapy and combination chemotherapy, leading to improved survival time, and complete cure has been documented [8]. A correct diagnosis of the tuniour ccll type is therefore esscntial, and a serum marker that would help to identify cases of small cell lung cancer and could be used for monitoring the efficacy of chemotherapy would be valuable. We have measured serum NSE concentrations in patients with small cell carcinomas of the lung, patients with adenocarcinoma of the lung, and patients with squamous cell carcinoma of the lung. The
Accepted tor publication January 2 . 1990. Address reprint requests t o Dr. P.K. Buamah, Unit for Cancer Studies and Department of Clinical Biochemistry, Thanct District General Hospital. St. Peter’s Road. Margate. Kent C T 9 4 A N . Eneland.
2
Buamah et al.
TABLE I. Summary of the Clinical Details of Patients With Small Cell Lung Cancer Case
Age (years)
I. 2.
Stage of disease
Initial NSE (cone. pgiliter)
Survival time (months)
65 51
26.0 45.9
11.0
3.
75
18.5
4.
61
9.0
5.
60
26.0
3.0
Cyclophosphamide, adriamycin, etoposide (4)
None
6.
56
11.2
25.0
Cyclophosphamide, adriamycin. etoposide (6)
5 MeV to chest 30 Gy in 12 days
7. 8. 9.
15
11.8
8.0
Cyclophosphamide. adriamycin, etoposide (3)
None
64 63
2.0
T,N,M,
19.9 14.7
13.0
Cyclophosphamide, adriamycin. etoposide (2) Methotrexate, ifosfamide, mesna (6)
None None
10.
53
TxNxM,
27.4
6.0
1 . Cyclophosphamide, adriamycin, and etoposide (3) 2. Ifosfamide and mesna (2)
None
I I.
68
T2NXMX
23.2
12.0
1. Cyclophosphamide, adriamycin, and etoposide (4) 2. Methotrexate (2)
None
12.
57
T,N,,M,
65.4
6.0
Cyclophosphamide, adriamycin, etoposide (4)
None None None
T2NxM,
Chemotherapy"
Radiotherapy
Cyclophosphamide adriamycin etoposide (4) 1 . Adrianiycin, ifosfamide. with tnesna (2) 2. Cisplatin, etoposide (2) 3. Cisplatin, ifosfamide I 1)
5 MeV to chest 5 MeV to chest 32 Gy in 24 days
18.0
1 , Cyclophosphamide, adriamycin, and etoposide (6) 2. Cisplatin, ifosfamide (3)
None
22.0
Etoposide (3) Ifodamide with mesna (3)
Co"" to chest 30 Gy in 14 days
7.0
13.
69
T,N,M,
12.9
6.0
Cyclophosphamide, adriamycin. etoposide (4)
14.
78
T,N,M,
7.3
13.0
15.
63
T,N,M,
5.3
23.0
Cyclophosphamide, vincristine, etoposide (4) Cyclophosphamide, adriamycin, etoposide (6)
16.
59
Liver metastases
132.2
12.0
1. Cyclophosphamide, adriamycin and etoposide (4) 2. 5 flurouracil, epirubicin, ifosfamide. with mesna (5)
5 MeV to chest 36 Gy in 21 days None
"Parentheses show number of courses administered
patients with small cell lung cancer were all receiving intravenous cytotoxic chemotherapy, and we assessed the serum enzyme concentrations in relation to the clinical assessment of the progress of the disease.
PATIENTS AND METHOD Twenty-eight patients with a histologically proven diagnosis of small cell lung cancer (SCLC), 28 patients with adenocarcinoma, and 62 patients with squamous cell carcinoma of the lung had blood collected for NSE estimation. Sixteen patients with SCLC (1 1 limited disease, five extensive disease) were monitored during subsequent chemotherapy. All patients received cyclophosphamide (100 mg mP2) adriamycin (50 mg m-2) and etoposide (75 mg m-2) on consecutive days, this cycle being repeated two to six times at 3-4 weekly intervals. Additional chemotherapeutic agents employed are shown in Table I. Formal assessment and restaging were made by repeated clinical, radiological, and bronchoscopic examinations. Blood samples for measurement of NSE concentration were obtained before chemotherapy and at regular intervals during the period of treatment. Samples were cen-
trifuged immediately on arrival in the laboratory, and the separated serum was frozen at -20°C until analysed. The NSE was measured using a double-antibody RIA kit from Pharmacia A.B. (Uppsala, Sweden). The assay has a dynamic range of 2-200 pg/liter and a between-batch coefficient of variation of 8%.
RESULTS The serum NSE concentrations of all 118 patients with lung cancer are summarised graphically in Figure 1. Employing an upper limit for healthy controls of 12.0 pg/ liter, which is in use in the author's laboratory, 20 of the 28 (71.4%) patients with SCLC had values greater than 12.0 pgiliter, and 13 of these (46.2%) had values greater than 25.0 pgiliter. By comparison, 22.2% of 90 patients with large cell lung cancer, i.e., 21.4% of 28 patients with adenocarcinoma and 22.5% of 62 patients with squamous cell carcinoma, had values > 12.0 pg/liter. Applying a cut-off of 25 pg/liter rather than 12 pglliter, then 46.2% of all cases of SCLC had a raised NSE level, in contrast to only 6.6% of those with other types of lung cancer (NSCLC). From these data, the predictive value of an NSE of > 12 pg/liter in differentiating SCLC from
220
180
..
140
N S E 100 Pg/L
80 60
40
. .. 0
20
C
.
t
. .
Small cell lung Adenocarcinoma cancer n = 28 n = 26
..
Squarnous cell carcinoma n = 62
Fig. 1 . Serum NSE concentration in patients with lung cancer. n. Number of patients.
NSCLC is only 50%, whereas the predictive value of an NSE of < 12 pgiliter in excluding SCLC is 91%. However, whereas the predictive value of an NSE of >25 pg/liter in identifying SCLC is increased to 68%, the predictive value of an NSE of
