Serum lactate dehydrogenase in the prognostic assessment of patients with oral squamous cell carcinoma :[PAUTHORS], Indian Journal of Dental Research (IJDR)

ORIGINAL RESEARCH
Year : 2022 | Volume : 33 | Issue : 2 | Page : 164--168

Serum lactate dehydrogenase in the prognostic assessment of patients with oral squamous cell carcinoma

Jimson Sudha¹, Amaladas Julius², Samson Jimson³, Kesavaram Padmavathy⁴,
¹ Research Scholar, Bharath Institute of Higher Education and Research (BIHER); Department of Oral Pathology and Microbiology, Sree Balaji Dental College and Hospital, BIHER, Chennai, Tamil Nadu, India
² Department of Biochemistry, Sree Balaji Dental College and Hospital, BIHER, Chennai, Tamil Nadu, India
³ Principal, Professor, Department of Oral and Maxillofacial Surgery, Sree Balaji Dental College and Hospital, BIHER, Chennai, Tamil Nadu, India
⁴ Department of Microbiology, Research Laboratory for Oral and Systemic Health, Sree Balaji Dental College and Hospital, BIHER, Chennai, Tamil Nadu, India

Correspondence Address:
Dr. Kesavaram Padmavathy
Department of Microbiology, Sree Balaji Dental College and Hospital, Velachery Main Road, Pallikaranai, Chennai, Tamil Nadu
India

Abstract

Background: Lactate dehydrogenase (LDH) has been proven to be a diagnostic marker in oral squamous cell carcinoma (OSCC). However, the prognostic value of serum LDH in OSCC is yet to be explored. The purpose of this study is to correlate the level of serum LDH with the degree of OSCC and to evaluate the role of serum LDH as a prognostic marker in OSCC. Methods: The investigators designed and implemented a prospective cohort study composed of patients with OSCC (n = 66) sub-grouped as follows: 2A—well-differentiated (n = 22), 2B—moderately differentiated (n = 22), 2C—poorly differentiated OSCC (n = 22), and normal healthy controls (n = 40). The primary outcome variable was the serum LDH measured at baseline (pre-treatment) and 2 and 12 months post-treatment in OSCC patients. The statistical analysis was performed using the student t-test and analysis of variance, and the P value was set at 0.05. Results: The habit of alcohol consumption alone as a single habit was found only in males (17.5%) (P = 0.3343), whereas betel quid chewing was more common among females (P = 0.0182). A significant difference was observed in the mean serum LDH between OSCC subjects (pre-treatment) (831.56 ± 93.43 IU/L) and controls (188.82 ± 25.53 IU/L), P < 0.00001. The baseline serum LDH was significantly higher in subgroup 2C (933.41 ± 46.1969 IU/L) than in the 2A (742.59 ± 46.5676 IU/L) and 2B (818.68 ± 58.1643 IU/L) subgroups (P = 0). There was a significant decline in the serum LDH within 2 months after treatment, and a further decrement was observed during a 12-month follow-up among the survivors of all three subgroups; P < 0.00001. Conclusion: Serum LDH can play a dual role as a reliable indicator of the degree of OSCC for decision-making in treatment modalities and as a prognostic marker of response to therapy.

How to cite this article:
Sudha J, Julius A, Jimson S, Padmavathy K. Serum lactate dehydrogenase in the prognostic assessment of patients with oral squamous cell carcinoma.Indian J Dent Res 2022;33:164-168

How to cite this URL:
Sudha J, Julius A, Jimson S, Padmavathy K. Serum lactate dehydrogenase in the prognostic assessment of patients with oral squamous cell carcinoma. Indian J Dent Res [serial online] 2022 [cited 2023 Mar 21 ];33:164-168
Available from: https://www.ijdr.in/text.asp?2022/33/2/164/358446

Full Text

Introduction

According to GLOBOCAN estimates 2018, southeast Asia is considered a high-risk region with a higher incidence (354,864 new cases) of cancers of the lip and oral cavity.[1] One of the most challenging and unanswered problems of the current days is the high burden of oral cancer in India, which accounts for 36% of the population among lower Human Development Index (HDI) countries. Cancer is the second leading cause of death worldwide, accounting for an estimated 9.6 million deaths, and especially, oral cancer is the most common cause of mortality in the Indian population.[2] Oral squamous cell carcinoma (OSCC) is a malignant neoplasm arising from the mucosal epithelium of the oral cavity and consists of heterogeneous cell populations with different biological characters. Tobacco usage is reported to be the single major risk factor for cancer and accounts for nearly 22% of cancer-related deaths globally.[3] According to the current World Health Organization report, tobacco usage (cigarettes and smokeless tobacco) and alcohol use are modifiable and avoidable risk factors that could contribute to a significant reduction in the burden of cancer.[4] Smoking and alcohol consumption account for nearly 75% of all cases of OSCC.[5],[6]

Early diagnosis and hence early initiation and effective response to cancer therapy would result in reduced morbidity, better survival rate, and lesser treatment costs. Owing to the higher incidence of oral cancer in our region, there is a need for evaluation of reliable biomarkers and standardizing accessible methods for screening, diagnostic, and prognostic purposes. Since the report of Warburg and his colleagues in 1924, numerous studies have documented the metabolic alterations and enzymes in cancerous tissues.[7] A wide range of tumour markers have been investigated for screening, diagnosis, prognosis, and monitoring response to therapy for oral cancer. A marked difference exists in the glycolytic activity between normal and malignant tissues. There occurs a metabolic switch from oxidative phosphorylation to increased glycolysis, even under hypoxic conditions, the Warburg effect. Increased mitotic index and increased glycolytic activity pave the way for elevated LDH in the tissue fluids and serum. Lactate Dehydrogenase (LDH) catalyses the oxidation of lactate to pyruvate with the simultaneous conversion of nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide hydrogenase. Previous studies have demonstrated increased serum LDH in subjects with cancer of the oral cavity, including buccal mucosa cancer, oral premalignant and malignant lesions, OSCC, and oral submucous fibrosis.[8],[9],[10],[11],[12],[13]

The study aimed to assess the significance of serum LDH as an early diagnostic and prognostic marker. This study was designed (1) to estimate and compare the levels of serum LDH in patients with different grades of OSCC and normal healthy subjects and (2) to explore the prognostic value of serum LDH post-treatment in patients with clinically and histopathologically diagnosed OSCC. The LDH levels were estimated at the baseline (pre-treatment) and at a time interval of 2 months and 12 months follow-up (post-treatment of OSCC).

Materials and Methods

The study protocol was reviewed and approved by the Institutional Human Ethical Committee, Sree Balaji Dental College and Hospital (SBDCH). Subjects who reported to the Department of Oral Pathology, SBDCH, were screened for oral cancer. The demographic details and details of habits including smoking/chewing of betel quid with or without tobacco/alcohol consumption were also recorded. Those who fulfilled the following inclusion criteria [age group of 20–75 years, both sexes, with habits (tobacco and/or smokeless tobacco/alcohol), clinically diagnosed, and histopathologically confirmed cases of OSCC] were recruited for the study. Those subjects with systemic illnesses that are known to increase serum LDH levels were excluded. The study group comprised controls (group 1) consisting of normal healthy subjects without habits (n = 40) and group 2 including patients with clinically and histopathologically confirmed cases of OSCC (n = 66), comprising 22 subjects in each grade, that is, subgroup 2A (well-differentiated), subgroup 2B (moderately differentiated), and subgroup 2C (poorly differentiated) lesions. Biopsy was performed at the Department of Oral Pathology, SBDCH. The histopathological grading of OSCC was performed as per Broder's grading system.[14]

Two millilitres of blood was collected by venipuncture under aseptic conditions. Blood was allowed to clot, and serum was separated and aliquoted in 1.5 mL microfuge tubes and stored at −20°C until use. Blood was collected only once from the normal healthy control subjects (group 1). Blood samples were collected at the baseline (pre-treatment) and at 2 months and 12 months after initiation of therapy (post-treatment) from the OSCC patients (group 2). Quantification of LDH was performed using a colorimetric assay which works on the following principle: LDH is an oxidoreductase that catalyses the conversion of lactate to pyruvate with the concomitant oxidation of NADH to NAD+. LDH activity in serum is proportional to the increase in absorbance due to the reduction of NAD.

Statistical analysis

Fisher's exact test (2-tailed) was used to analyse the prevalence of habits between males and females of group 2 (OSCC). Student's t-test was performed to calculate the statistical significance of the mean LDH levels between the groups. One-way analysis of variance (ANOVA) was performed to assess the statistical difference in the mean LDH levels between the subgroups.

Results

Of the 22 subjects with well-differentiated OSCC (group 2A), majority were males (n = 19) compared to females (n = 3). All female subjects (n = 3) were betel quid chewers, whereas the male subjects were either smokers (n = 5, frequency 5–15 cigarettes/day), betel quid chewers (n = 4, frequency 4–6 times/day), alcohol consumers (n = 4, frequency ≥4 days/week), and mixed habits (smoking/chewing/alcohol, n = 6). Based on TNM staging, 15 subjects were classified as TNM stage I (T1N0M0), whereas 7 subjects belonged to TNM stage II (T2N0M0). The majority of the group 2A subjects had lesions in their buccal mucosa (n = 13) followed by tongue (n = 5) and palate (n = 4).

Among the 22 subjects with moderately differentiated OSCC (group 2B), the majority were males (n = 20) compared to females (n = 2). Male subjects were either smokers (n = 8, frequency 7–15 cigarettes/day), betel quid chewers (n = 6, frequency 6–7 times/day), alcohol consumers (n = 4, frequency ≥4 days/week), and mixed habits (smoking/chewing/alcohol, n = 2). Of the 2 female subjects, 1 female was a betel quid chewer (frequency 6–7 times/day), and the other subject had mixed habits (smoking/chewing/alcohol). Based on clinical examination, 18 subjects were classified as TNM stage 1II (T3N1M0), whereas 4 subjects belonged to TNM stage IVA (T1N2M0). The majority of the group 2B subjects had lesion in their buccal mucosa (n = 15), followed by tongue (n = 4) and palate (n = 3).

The majority of the subjects with poorly differentiated OSCC (group 2C, n = 22) were males (n = 18) compared to females (n = 4). Of the 18 male subjects, 9 were smokers (frequency 7–18 cigarettes/day), 4 were betel quid chewers (frequency 3–4 times/day), 2 were alcohol consumers (frequency ≥5 days/week), and 3 had mixed habits (smoking/chewing/alcohol). Of the 4 female subjects, 1 subject was a smoker (frequency 15 times/day), 2 subjects were betel quid chewers (frequency 4–5 times/day), and 1 subject had mixed habits (smoking/chewing/alcohol). Based on clinical examination, 21 subjects were classified as TNM stage 1VA (T4aN2M0 = 15 and T4bNanyM0 = 6), whereas 1 subject belonged to TNM stage IVC (TanyNanyM1). The majority of the group 2B subjects had lesion in their buccal mucosa (n = 15), followed by tongue (n = 4) and palate (n = 3).

The baseline (pre-treatment) mean serum LDH level was significantly higher (831.56 IU/L) among the subjects with OSSC (n = 66) compared to the mean (188.82 IU/L) of the normal healthy subjects (n = 40) (P < 0.00001) [Table 1]. Intra-group comparison showed that there was an increase in serum LDH levels among different grades with a rise from well-differentiated to poorly differentiated OSCC. Among the OSCC subjects, the mean serum LDH level at the baseline (pre-treatment) was higher in subgroup 2C (poorly differentiated lesions) (933.41 IU/L) compared to subgroup 2A (well-differentiated) (742.59 IU/L) and subgroup 2B (moderately differentiated lesions) (818.68 IU/L) [Table 1].{Table 1}

A significant statistical difference (P < 0.00001) was observed in the mean LDH levels between the subgroups 2A, 2B, and 2C at different time intervals, both pre- and post-treatment [Figure 1]. The pre- and post-treatment comparison of LDH with different grades of OSCC showed a significant decline in the mean LDH levels post-treatment in subjects within each subgroup, 2A (well-differentiated), 2B (moderately differentiated), and 2C (poorly differentiated lesions) (one-way ANOVA, P = 0) [Figure 1].{Figure 1}

Comparison of the mean serum LDH levels within groups using the t-test showed a statistically significant decline in levels after 2 months and 12 months of treatment irrespective of chemotherapy, radiotherapy, or surgery [Table 2] and [Table 3].{Table 2}{Table 3}

Discussion

In group 2 (OSCC), the prevalence of the habit of smoking was more common among the male subjects (38.5%) compared to females (11.1%). However, this was not statistically significant (P = 0.1456). Mixed habits were observed in both males (19.3%) and females (22.2) (P = 1.000). The habit of alcohol consumption alone as a single habit was found only in males (17.5%) but not in females (0%) (P = 0.3343). In our study, the majority of the females of groups 2 (OSCC) were betel quid chewers. Betel quid chewing was a significantly more common habit among females (66.6%) compared to males (24.5%) (P = 0.0182). There was no statistically significant difference in the habits between male and female subjects within each subgroup 2A, 2B, and 2C (P > 0.05).

Biochemical alterations that occur in malignancy are well detectable in the blood. Biomarkers are currently relied upon for the prediction and early detection of oral cancer and hence early initiation of therapy and thereby minimisation of mortality. LDH is considered as a reliable tumour marker for the detection and assessment of the potential transformation of oral premalignant lesions into malignant OSCC.[15]

The results of our study indicate a significant rise in the serum LDH levels in patients with OSCC lesions (831.56 IU/L) in comparison with normal healthy individuals (188.82 IU/L). Our results are in concurrence with the findings of Pereira et al., 2015,[16] and D'Cruz and Pathiyil, 2015,[15] who reported increased serum LDH and salivary LDH in patients with OSCC compared to the normal healthy controls. The normal values of serum LDH in adult males and adult females are 135–225 U/L and 35–214 U/L, respectively. This drastic difference in LDH could be attributed to an altered rate of synthesis of these enzymes within the tissue of origin, altered amount of the enzyme-forming tissue, or an alteration in the permeability of the cell membrane brought about by the pathological condition.

A significant correlation exists between the degree of differentiation of OSCC and the levels of serum LDH. Mitotic differentiation is the highest in the poorly differentiated type followed by the moderately differentiated type and the well-differentiated type.[17] In our study, the level of serum LDH was found to have an inverse correlation with the histological grade of malignancy, that is, poorly differentiated OSCC was associated with higher LDH values and vice versa. There was a gradual increment in the level of serum LDH from well-differentiated OSCC to poorly differentiated OSCC, signifying that LDH levels decrease as the degree of tumour increases. This is in agreement with the findings of D'Cruz and Pathiyil, 2015, have reported an increased salivary LDH level in poorly differentiated OSCC (620.35 IU/L) compared to the moderately differentiated (484.18 IU/L) and well differentiated (355.83 IU/L).[15] Also, Pereira et al., 2015, who reported increased serum LDH in patients with moderately differentiated OSCC (988.50 IU/L) compared to the well differentiated cases (743.30 IU/L).[16] This is in agreement with the findings of D'Cruz and Pathiyil, 2015, have reported an increased salivary LDH level in poorly differentiated OSCC (620.35 IU/L) compared to the moderately differentiated (484.18 IU/L) and well differentiated (355.83 IU/L).[15]

Oral cancer has a higher mortality rate and accounts to nearly 0.3 million deaths per year among the Indian population.[2] Early initiation of treatment offers the best prognosis and a better chance of survival. In our study, there was a significant decline in the post-treatment levels of serum LDH irrespective of radiotherapy, chemotherapy, or surgery in all grades of OSCC. This is in line with the findings of Liaw et al., 1997,[18] who reported that serum LDH levels correlate with the clinical responsiveness to systemic chemotherapy in nasopharyngeal carcinoma. In this follow-up study of 66 patients with OSCC who underwent cancer therapy, serum LDH levels decreased gradually at 2 months post-treatment and further reduced at 12 months post-treatment. However, 3 subjects died, and 7 subjects were lost to follow-up.

Conclusion

Estimation of serum LDH may be used to screen the cases of oral malignancy as an adjunct to clinical diagnosis. In this longitudinal study, it was found that the level of serum LDH is reflected in the clinical course; hence, it could be concluded that serum LDH might be useful to assess the severity of OSCC and is a prognostic indicator of response to therapy. To the best of our knowledge, this is the first Indian follow-up study on the assessment of LDH soon after (2 months) and after long-term treatment (12 months) as a prognostic marker of response to therapy. Hence, serum LDH levels might give us a clue about the degree of OSCC and clinical value in cancer management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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