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Role of squamous cell carcinoma antigen in monitoring of treatment response of cervical and vaginal malignancies
This article was originally published by Thieme Medical and Scientific Publishers Private Ltd. and was migrated to Scientific Scholar after the change of Publisher.
Abstract
Introduction: As per GLOBOCAN 2012 report Worldwide fourth most common cancer in the female is cervical cancer and approximately 528,000 new cases was found in 2012 in large majority of global burden was found in less developed country. India, the second most populous country in the world, accounts for 27% of the total cervical cancer deaths. The aim of this study was to assess the efficacy of squamous cells carcinoma antigen (SCC-Ag) in monitoring of response to treatment in cervical and vaginal cancer patients.
Materials and Methods: This prospective case–control study was carried out over a period of 1 year in the Department of Obstetrics and Gynecology in collaboration with the Department of Internal Medicine and Pathology. Histopathologically confirmed study group included 8 cases of Stage I, 15 cases of Stage II, 15 cases of Stage III, 8 cases of Stage IV cervical malignancy, and 5 cases of vaginal carcinoma. About 15 healthy cervical cytology-negative women were taken as controls.
Results: Out of 51 cancer cases SCC-Ag level were determined in only Stage I, II, III, and IV cases, assess the response to treatment. The mean SCC-Ag level in all four stage groups decreased significantly after post treatment as compared to pre treatment (P < 0.001) and the decrease in post treatment SCC-Ag level increased linearly with stage severity. Similarly, comparing the total or overall (Stage I + Stage II + Stage III) mean change (pre-post) in SCC-Ag level, t-test further revealed significant (P < 0.001) and decrease of 66.2% at posttreatment as compared to pretreatment.
Conclusion: SCC-Ag might be a useful marker in monitoring the response to treatment.
Keywords
Cervical cancer
International Federation of Gynecology and Obstetrics staging
radiotherapy
squamous cell carcinoma antigen
Introduction
According to the WHO cervical cancer contributes 12% of all female cancers and it is the most common gynecological malignancy in developing countries.1,2 Recent reports state that 1.32 lakhs new cases are diagnosed per year and 74,000 annual deaths are reported in India.3 India, the second most populous country in the world, accounts for 27% of the total cervical cancer deaths.4 Squamous cells carcinoma antigen (SCC-Ag) is subfraction of TA-4 which is a tumor-associated antigen first described by Kato and Torigoe in 1977.5 It belongs to the family of serine protease inhibitors. Acidic isoform of SCC-Ag was found in tumor cells, especially those located at the periphery of the tumors and in the serum of cancer patients and it plays an important role in suppressing apoptotic cell death.6,7 SCC-Ag suppresses the activity of caspase-3 and caspase-9 via downregulation of P38 MAPK and/or MKK3/MKK6, thus SCC-Ag in tumor cells help to protect cancer cells from apoptotic cell deaths.
In the present era, despite various screening methods such as conventional exfoliative cervicovaginal cytology, liquid-based cytology, and human papillomavirus testing, which is quite effective also in diagnosing the early lesions. However, none of the screening techniques could predict the natural history of disease process or the progressive nature of lesion. Accumulating experimental evidence suggest that the dysregulation of apoptosis may play a role in the pathogenesis of gynecological tumor for this purpose, it is important to identify a reliable biomarker to better characterized the natural history of disease. At present, various immunohistochemical markers are present, but no definite serum biomarker is available; so, it is difficult to monitor the treatment response. Thus, this study was planned to evaluate the role of SCC-Ag as a tumor marker in monitoring the treatment response in patients of cervical and vaginal malignancy. The aim of this study was to assess the efficacy of SCC-Ag in monitoring of response to treatment in cervical and vaginal cancer patients.
Materials and Methods
This prospective case–control study was carried out over a period of 1 year in the Department of Obstetrics and Gynecology in collaboration with the Department of Internal Medicine and Pathology at King George's Medical University, Lucknow. Ethical clearance was obtained from the Institutional Ethics Committee of this university. After informed and written consent, 66 subjects were enrolled in this study. According to International Federation of Gynecology and Obstetrics (FIGO) staging, histopathologically confirmed study group included 8 cases of Stage I, 15 cases of Stage II, 15 cases of Stage III, 8 cases of Stage IV cervical malignancy, and 5 cases of vaginal carcinoma. Fifteen healthy cervical cytology-negative women were taken as controls.
FIGO, Stage I cancer patients were treated surgically (Wertheim's hysterectomy), Stage II and Stage III, and 4 cases of vaginal carcinoma were treated by concurrent chemoradiation and Stage IV cervical carcinoma and one case of vaginal carcinoma were treated by palliative chemotherapy and then radiotherapy (RT) was given.
Women suffering from Pemphigus, psoriasis, or eczema were excluded from the study.
Intervention
Five milliliter venous blood samples were drawn into a sterile vial from all patients before treatment. A second sample was drawn, 6 weeks after completion of treatment from Stage I, II, III, and IV patients. Samples were kept at 4°C, centrifuged at 6000 rpm for 15 min, and then immediately frozen at −20°C until assay. Serum SCC-Ag levels (SCC-Ag) were estimated by ELISA technique using enzyme-linked immunosorbent assay kit as per producer protocol (USCN life sciences Inc., Export Processing zone, Economic and development zone, China).
The microtiter plate of kit has been precoated with an antibody specific to SCC-Ag standard and blood sample was then added to the appropriate microtiter plate wells coated with a biotin-conjugated antibody preparation specific for SCC-Ag2. Avidin conjugated to horseradish peroxidase (HRP) is added to each microplate well and incubated.
This is sandwich ELISA kit for in vitro quantitative measurement of SCC-Ag2 in human serum (Uscn, Life Science Inc., Export Processing Zone, Economic and Technological Development Zone, China). The microtiter plate of kit has been precoated with an antibody specific to SCC-Ag2. Standard and sample are then added to the appropriate microtiter plate wells coated with a biotin-conjugated antibody preparation specific for SCC-Ag2. Avidin conjugated to HRP is added to each microplate well and incubated. After 3,5,3’,5’-tetramethylbenzidine substrate solution is added, only those wells that contain SCC-Ag2, biotin-conjugated antibody, and enzyme-conjugated avidin exhibited a change in color. The enzyme–substrate reaction is terminated by the addition of sulfuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm ± 10 nm. The concentration of SCC-Ag2 in the sample is then determined by comparing the optical density of the sample to the standard curve.
Statistical analysis
SCC-Ag levels in different clinical stages of invasive cervical and vaginal lesions were measured as mean ± standard deviation. Groups were compared by one-way analysis of variance (ANOVA), and the significance of mean difference between the groups was done by Tukey's post hoc test. Groups were also compared by factorial two-way ANOVA, and the significance of mean difference within and between the groups was done by Tukey's post hoc test. Groups were also compared by repeated measures ANOVA. Discrete (categorical) groups were compared by Chi-square test. A two-sided (α = 2) P < 0.05 was considered statistically significant. All analyses were performed on STATISTICA software (Windows version 6.0, Dell products, Intel Corporation, US).
Results
Out of 51 cancer cases, pre- and post-treatment SCC-Ag level was determined in only Stage I, II, III, and IV cases, assess the response to treatment. In this study, we had not assessed posttreatment SCC-Ag level of vaginal carcinoma cases, as we considered this a separate entity. In our study, out of 51 cases, majority of cases were moderately differentiated 42 (82.4%) and mean SCC-Ag level of these patients was 2.88 ± 1.35.
Nine (17.6%) cases were poorly differentiated and mean SCC-Ag level of these patients was 3.36 ± 0.87. There was no statistically significant difference between four groups with respect to age, diet, and tobacco intake (P > 0.05) Table 1. The cases those received RT had significantly higher premean SCC-Ag levels as compared to those who underwent hysterectomy Table 2 and Figure 1.
- Premean squamous cells carcinoma antigen level according to treatment given to cases. nsP > 0.05 or *P < 0.05 as compared to hysterectomy
|
Characteristics |
Control (n=15) (%) |
Cases (n=51) (%) |
P |
|---|---|---|---|
|
Age (years) |
|||
|
≤45 |
7 (46.7) |
29 (56.9) |
0.281 |
|
>45 |
8 (53.3) |
22 (43.1) |
|
|
Religion |
|||
|
Hindu |
12 (80.0) |
51 (100.0) |
0.008 |
|
Muslim |
3 (20.0) |
0 (0.0) |
|
|
Tobacco intake |
|||
|
Nonuser |
12 (80.0) |
26 (51.0) |
0.131 |
|
User |
3 (20.0) |
25 (49.0) |
|
|
Diet |
|||
|
Nonvegetarian |
7 (46.7) |
15 (29.4) |
0.304 |
|
Vegetarian |
8 (53.3) |
36 (70.6) |
|
|
Age at 1st intercourse (years) |
|||
|
≤16 |
11 (73.3) |
39 (76.5) |
<0.001 |
|
>16 |
4 (26.7) |
12 (23.5) |
|
|
Contraception used |
|||
|
Temporary |
4 (26.7) |
5 (9.8) |
0.026 |
|
Nonuser |
8 (53.3) |
41 (80.4) |
|
|
Tubal ligation |
3 (20.0) |
5 (9.8) |
|
Characteristics |
n |
Pre-SCC-Ag (ng/ml) (mean±SD) |
T/F |
P |
|---|---|---|---|---|
|
Histopathological examination report |
||||
|
Moderately differentiated |
42 |
2.88±1.35 |
1.01 |
0.316 |
|
Poorly differentiated |
9 |
3.36±0.87 |
||
|
Treatment |
||||
|
Hysterectomy |
8 |
2.10±0.55 |
3.75 |
0.031 |
|
Concurrent chemo RT |
34 |
3.28±0.99 |
||
|
Palliative CT + RT |
9 |
2.52±2.15 |
||
|
Treatment response |
||||
|
Complete responder |
32 |
3.04±0.92 |
4.14 |
<0.001 |
|
Nonresponder |
6 |
4.73±0.90 |
RT - Radiotherapy; CT - Chemoradiotherapy; SCC-Ag - Squamous cell carcinoma antigen; SD - Standard deviation
The mean SCC-Ag level in all four stage groups decreased significantly (P < 0.001) after posttreatment as compared to pretreatment, and the decrease in posttreatment SCC-Ag level, increased linearly with stage severity Table 3. Further, comparing the change/or decrease (pre- to post-treatment) of four stages (FIGO I–IV). ANOVA (F = 16.83, P < 0.001) followed by Tukey's test revealed significantly (P < 0.01) higher decrease in Stage III as compared to both Stage I and Stage II; however, the decrease did not reach statistical significance (P > 0.05) when compared between Stage I and Stage II Table 3.
|
Stage groups |
n |
Pre |
Post |
Mean change (pre-post) |
Percentage mean change |
P |
|---|---|---|---|---|---|---|
|
Stage I |
8 |
2.10±0.55 |
0.50±0.08 |
1.61±0.55 |
76.4 |
<0.001 |
|
Stage II |
15 |
3.15±0.84 |
1.22±0.64 |
1.93±0.59 |
61.2 |
<0.001 |
|
Stage III |
15 |
4.12±0.89 |
1.35±0.57 |
2.77±0.76 |
67.3 |
<0.001 |
|
Stage IV |
8 |
3.15±0.87 |
1.12±0.59 |
2.03±0.58 |
62.2 |
<0.001 |
|
Vaginal carcinoma |
5 |
0.72±0.14 |
- |
- |
- |
- |
|
Total |
51 |
3.31±1.10 |
1.12±0.62 |
2.19±0.80 |
66.7 |
<0.001 |
Similarly, when comparison was done between total pre- and post-treatment values of SCC-Ag levels in Stage I, II and Stage III, t-test further revealed a significant difference (P < 0.001) and decrease of 66.7% in SCC-Ag levels posttherapy Table 3 and Figure 2.
- Overall mean change in squamous cells carcinoma antigen level of cases. (pretreatment vs. posttreatment). ***P < 0.001 as compared to pretreatment
The mean SCC-Ag level in all three groups was compared separately, and significant difference was observed between Stage I versus Stage III pretreatment (P < 0.001), posttreatment difference (P < 0.070) as compared to other stages Table 4.
|
Comparisons |
Pretreatment |
Posttreatment |
|---|---|---|
|
Stage I versus Stage II |
0.013 |
0.175 |
|
Stage I versus Stage III |
<0.001 |
0.070 |
|
Stage II versus Stage III |
0.004 |
0.996 |
Discussion
In the present study, though the pretreatment mean SCC-Ag levels were higher in poorly differentiated squamous cell carcinoma as compared to moderately differentiated carcinoma but this difference was statistically not significant. Other study reported that close relation of SCC-Ag with squamous epithelium tumor and its raised level was more associated with more differentiated type of carcinoma.8
However, the clinical data revealed that there was no significant difference in the incidence of positive serum SCC-Ag concentration between undifferentiated type and more differentiated type of carcinoma.9
Authors reported elevated SCC-Ag levels in squamous cell carcinoma cases in terms of different percentage of patients having elevated SCC-Ag level in each stage. Higher SCC-Ag level in Stage III, cervical cancer (P < 0.001),10 but in our study, all cases were had elevated SCC-Ag level and more rise with Stage III malignancy; similarly, other reported significantly higher SCC-Ag levels for Stage III lesions as compared to Stage I and Stage II.
It was higher in patients with higher stages of squamous cell carcinoma, and in the present study, it was observed that SCC-Ag level was increase with the increasing stage of cervical malignancy.
A balance between apoptosis and cell proliferation is crucial features for the maintenance of homeostasis in multicellular organism.11 It is now well established that apoptosis plays an important role in the regulation of tumor progression.12,13
In malignant cell, apoptosis rate was lower as compared to normal cells but in esophageal cancer rate of apoptosis was higher in well-differentiated esophageal tumor than in poorly differentiated tumor.14
Other study reported that correlation between SCC-Ag and histological grade in esophageal squamous cell carcinoma.15 In the present study, hysterectomy was done in 15.7% cases concurrent chemo-RT given in 66.7% cases and neoadjuvant chemotherapy (chemoradiotherapy + RT) was given in 17.6% cases. After treatment response was recorded in Stage I, II, and III in terms of decline in SCC-Ag level, 84.2% cases were responded completely to treatment and 15.8% were not responded to treatment. The cases those received RT had significantly (P < 0.05) higher premean SCC-Ag level as compared to patients with Stage I. Nonresponder patient had significantly (P < 0.001) elevated premean SCC-Ag level as compared to responder.
Author reported that an elevated pretreatment SCC-Ag can be used to predict the clinical response to neoadjuvant chemotherapy.16
Another study reported that patients with residual disease in duration and persistently elevated SCC-Ag level at 2–3 months after RT had a significantly higher incidence of treatment failure.17
In our study, SCC-Ag level shows rising trend with tumor size. Reduction of SCC-Ag level more than 50% was observed after treatment. Significant difference was observed in respect to percent change in SCC-Ag level with either microscopic lesion or lesion of more than 4 cm in size. Here, change in SCC-Ag level following treatment was generally universally similar and was less affected by different variables. Hence, prediction of treatment response was difficult and not feasible. Pretreatment SCC-Ag level, along with tumor size was useful in predicting recurrence and the need for postoperative adjuvant therapy.18
Few study reported that pre-RT SCC-Ag levels significantly correlated with pre-RT tumor volume and recurrence were identified in patients with elevated pre-RT SCC-Ag levels.19,20,21 In our study, >50% reduction in SCC-Ag level after treatment but difference was statistically not significant. Thus, this tumor marker might also be useful for monitoring the treatment effects and has prognostic value.
In advanced cancers, pretreatment serum SCC-Ag levels are associated with clinical stages, tumor sizes, and lymph node involvement. Furthermore, over 6 ng/ml of serum SCC-Ag level shows a significant independent effect on survival and disease-free survival.22 Even in the early stage of uterine squamous cell carcinomas, elevated serum SCC-Ag levels predict pelvic lymph node involvement and are associated with a poor prognosis.23
Serum SCC-Ag levels are especially useful for monitoring treatment efficacy, disease progression, and recurrence. In general, increased serum SCC-Ag levels reflect disease progression and poor prognosis in squamous cell carcinomas.24
Conclusion
Thus, the combination of clinical pelvic examination and SCC-Ag levels provides useful information for the further need of treatment. If SCC-Ag increases during follow-up, then these patients were more careful worked up for locoregional recurrence.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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