Comparisons of Propensity Score Methods for Time to Event Outcomes: Evaluation through Simulations and Oral Squamous Cell Carcinoma Case Study

Author(s):  
Sophie Ma ◽  
Badr Id Said ◽  
Ali Hosni ◽  
Wei Xu ◽  
Sareh Keshavarzi

Introduction & Objective: In observational studies, it is recommended to use propensity score (PS) methods or covariate adjustment for confounding effect adjustment. However, few guidelines are available regarding the choice of PS approaches or covariate adjustment for the best performance in a particular data. In this study, we compared different PS methods and conventional covariate adjustment to investigate the treatment effect for the overall population on time-to-event outcomes. Methods: In the Monte Carlo simulations, we compared the hazard ratio (HR) and precision estimated using covariate adjustment and eight different PS approaches, including matching, stratification, and inverse probability of treatment weighting (IPTW). In the Oral Squamous-Cell Carcinoma Cancer case study, we applied the aforementioned PS approaches to compare the effect of receiving post-operative radiation therapy (PORT) and having engraftable tumors on different time-to-event clinical outcomes. Results: In the simulations, both IPTW and covariate adjustment produced unbiased HR estimates with small uncertainty. In the case study, covariate adjustment showed that patients with engraftable tumors were twice as likely to have local/regional recurrence (HR 1.98 [1.23, 3.18], p-value<0.005) and any recurrence or death (HR 2.02 [1.38, 2.96], p-value<0.001); patients received PORT were twice as likely to develop either local, regional, or distance recurrence (HR 2.12 [1.32, 3.41], p-value<0.005). Results produced by IPTW were consistent with covariate adjustment method (within ± 0.1 differences). Conclusion: Covariate adjustment and the IPTW method performed well across simulations and the case study. In practice, care should be taken to select the most suitable method when estimating the treatment, exposure or intervention effect on time-to-event outcomes.

2020 ◽  
Vol 10 (1) ◽  
pp. 3-5
Author(s):  
Parometa Barma ◽  
Ibrahim Khalil ◽  
Tanzima Yeasmin

Developing country like Bangladesh among 90% of oral malignant neoplasm are arising from squamous layer of oral epithelium which are third leading of this country with severe disfiguration, functiolaesa, psychological impairments and socio-economic hardship. In this study we found the prevalence of OSCC was 6.5% among total cancer patients in the two tertiary level hospitals of Bogura. Male (70%) are affected more than in females (30%). In response to male and female parameter, sex distribution ratio was 2.3:1. The prevalent average age was 55.40 years. About 80% of ulcer site was buccal mucosa then 10 % were lip mucosa. About 80% people were habituated by betel nut, leaf with tobacco chewers. Moreover 46.7% of them were maltreated by quack doctors before. Majority of the patient was in Grade II (56.7%). Correlation between variable in respect of age and cancer grading was explained. According to these study OSCC patients in north bangle region like Bogura was quite high on ( significant p-value ≤ 0.05). Description of oral squamous cell carcinoma on the basis of demographic and clinical profile was the major aim . Most of the cases report with intermediate grade of the disease which often leads to decrease the chance of survival of a patient. So new strategies should be considered to overcome the present situation must be undertaken by oral health programs for the early diagnosis and prevention, build up awareness and management and follow up of oral cancer. Update Dent. Coll. j: 2020; 10 (1): 3-5


2016 ◽  
Vol 6 (12) ◽  
pp. 1013-1017
Author(s):  
G Dundy ◽  
H Kumar ◽  
A Singh ◽  
A Chandarakant

Background: Mutation of p53 gene is one of the most common events in oral carcinogenesis. Accumulation of p53 protein has also been detected in premalignant lesions.Materials and Methods:  This study included 40 biopsy samples, which were received in department of pathology, Sarojini Naidu Medical College, Agra, to ascertain p53 expression by immunohistochemically, in patients with oral squamous cell carcinomas and to correlate its expression with histological grade, different sites in oral cavity and tobacco intake/smoking habits.Results: Out of 40 biopsies of oral mucosa, 03 showed normal oral mucosa and 37 were diagnosed as squamous cell carcinoma (SCC), most patients were in 5th and 6th decade and majority (86.5%) of oral SCC were males with buccal mucosa being the most common site. There was a statistically significant difference in p53 expression between oral SCC and normal oral mucosa (p value <0.05). Of total 37 cases, 12 cases were well differentiated type, 16 moderately differentiated and 09 of poorly differentiated type of SCC. In each category, about two thirds were positive for p53 staining. Out of total 37 cases of oral SCC, 64.9% were positive and 35.1% were negative for p53 expression, 34 cases had positive history of tobacco intake/smoking habits, of which 23 cases were positive while 11 cases were negative for p53 staining.Conclusion: Abnormal p53 protein was detected in 64.9% of oral squamous cell carcinoma, but not in normal oral mucosa. p53 expression was associated with malignant transformation of oral mucosa. 


Author(s):  
Nattinee Charoen ◽  
Kitti Jantharapattana ◽  
Paramee Thongsuksai

Objective: Programmed cell death ligand 1 (PD-L1) and mammalian target of rapamycin (mTOR) are key players in host immune evasion and oncogenic activation, respectively. Evidence of the prognostic role in oral squamous cell carcinoma (OSCC) is conflicting. This study examined the associations of PD-L1 and mTOR expression with 5-year overall survival in OSCC patients. Material and Methods: The expressions of PD-L1 and mTOR proteins were immunohistochemically evaluated on tissue microarrays of 191 patients with OSCC who were treated by surgery at Songklanagarind Hospital, Thailand from 2008 to 2011. Cox regression analysis was used to determine independent prognostic factors. Results: PD-L1 expression was observed in 14.1% of cases while mTOR expression was present in 74.3% of cases. Females were more likely to have tumors with PD-L1 (p-value=0.007) and mTOR expressions (p-value=0.003) than males. In addition, lower clinical stage and well differentiated tumor are more likely to have mTOR expression (p-value= 0.038 and p-value<0.001, respectively). Cox regression analysis showed that age, tumor stage, nodal stage, combined surgical treatment with radiation or chemoradiation therapy, surgical margin status, PD-L1 expression and mTOR expression are independent prognostic factors. High PD-L1 expression (hazard ratio (HR) 3.14, 95% confidence interval (CI), 1.26–7.79) and high mTOR expression (HR 1.69, 95% CI, 1.00–2.84) are strong predictors of poor outcome. Conclusion: A proportion of OSCC expressed PD-L1 and mTOR proteins. Expression of PD-L1 and mTOR proteins are strong prognostic factors of OSCC.


2020 ◽  
Vol 11 (SPL3) ◽  
pp. 1850-1854
Author(s):  
Anubhav Das ◽  
Gheena S ◽  
Ravindra Kumar Jain

Oral Squamous Cell Carcinoma (OSCC) is the most common neoplasm representing more than 80% of all oral cancer cases. Squamous cell carcinoma is defined as a “malignant epithelial neoplasm exhibiting squamous differentiation as characterized by the formation of keratin and/ or the presence of intercellular bridges”.Most of the epidemiological studies have revealed that heavy smoking and alcohol intake are the most important risk factors for oral cancer. Poor dental hygiene, accompanied by tooth loss, certain oncogenic viruses have been associated with an increased risk of cancer. The purpose of this study was to analyze the gender and age predilection of habits and oral cancer among an outpatient population visiting a dental college. This was a retrospective study (2019-2020) in which data on 34 Oral Squamous Cell Carcinoma(OSCC) were investigated. The patient records were reviewed and analysed between January 2019 and March 2020. All the 34 patient data were tabulated in excel, reviewed and was classified according to the border's grading system. Following which data was imported to SPSS software by IBM for descriptive statistical analysis and chi-square test was performed. A significant association between OSCC and age group (45-50 Years) was observed though it was statistically insignificant. (p value=0.64). Males have a higher incidence of OSCC compared to females in the same age group. A significant association is observed between Gutka, Smoking and pan chewing with OSCC. OSCC is the most commonly occurring oral cancer and there is a high predilection of the OSCC with age, gender and habits. Dentists play a key role in screening, detection and treatment of oral malignancies and can help in educating the public to bring about more awareness towards prevention of Oral Cancer.


Author(s):  
Malak Abdulrahman Seid Ahmed ◽  
Nazik Omer ◽  
Ahmed M. Suliman ◽  
Mona Ellaithi

Background: Cyclin D1 expression regulates normal cell cycle. Its deregulation or overexpression may cause disruption in the normal cell cycle control and lead to cancer progression. In this study, we aimed to study the expression of cyclin D1 in oral squamous cell carcinoma (OSCC) and find its association with the different grades of oral tumors, if any.  Methods: This cross-sectional study included 40 formalin-fixed paraffin-embedded tissue blocks specimens of OSCC with variable grades. The expression of cyclin D1 was evaluated through immunohistochemical (IHC) staining. Results: There were 9 female and 31 male samples, with a male-to-female ratio of 3.4:1. The age ranged between 25 and 90 years with an average age of 65.5 years. Twenty-five (62.5%) samples were diagnosed as well-differentiated squamous cell carcinoma (WDSCC) and fifteen (37.5%) as poorly differentiated squamous cell carcinoma (PDSCC). No cases of moderately differentiated squamous carcinoma were included in the study. The expression of cyclin D1 was detected in the cases of WDSCC and a lesser expression was seen in the PDSCC with a P-value of 0.0003, OR 1581 and 95% CI (29.8239 to 83810.7113). Conclusion: Cyclin D1 is expressed in  OSCC and stronger expression was detected in WDSCC.


Author(s):  
Bhagyalakshmi Atla ◽  
Sreevalli Prabhakula ◽  
Seeram Satish Kumar ◽  
Lakshmi Saraswathi Boni

Background: Despite the advance of therapeutic approaches, the morbidity and mortality of oral squamous cell carcinoma have not improved significantly. The invasion potential of oral squamous cell carcinoma is conferred by their ability to utilize Matrix metalloproteinase that are produced by the host’s stromal cells. In the present study an effort was made to analyse the role of clinical features and risk factors in the causation of oral squamous cell carcinoma and expression of Matrix metalloproteinase-9 (MMP-9) was studied in various grades of squamous cell carcinoma with its role in metastasis.Methods: The present study is an hospital based prospective study for a period of two years at the department of pathology from August 2014 to July 2016 consisting of 88 cases of oral squamous cell carcinoma. Tissue for H and E sections were fixed in 10% formalin and subjected to routine paraffin embedded processing and stained with hematoxylin and eosin.Results: Total number of cases of oral squamous cell carcinoma analyzed were 88, out of which 65 cases were subjected to MMP 9 expression by random selection on Immunohistochemistry. Majority of cases occurred in the age group of 41-50 years with male: female ratio of 1.4:1. In stage I and II the expression of MMP-9 is low in 37 cases (82.22%) and in stage III the expression is high in 14 cases (70%) with P value <0.05 (significant).Conclusions: Matrix metalloproteinases could act as a therapeutic target and could play an important role in effective treatment strategies of oral cancer.


Author(s):  
Naghmeh Emami ◽  
Naghmeh Bahrami ◽  
Masoumeh Mirzaei ◽  
Abdolreza Mohamadnia

Introduction: Oral Squamous Cell Carcinoma (OSCC) is one of the most common oral malignancies, which accounts for 80-90% of malignant neoplasms of the oral cavity. MicroRNAs (miRNAs) are small RNA molecules that regulate post-transcriptional gene expression by targeting mRNAs. Materials and Methods: In this case-control study, 40 patients with oral squamous cell carcinoma and 40 healthy individuals as control were studied. Blood samples were collected from both groups. Also, 30 cancer tissue samples and 30 healthy tissue samples were prepared and evaluated. RNA was extracted from collected peripheral blood and tissue samples and evaluated for the expression level of miR-494 via real-time PCR technique. P. value values<0.05 were considered statistically significant. Results: The expression level of miR-494 in serum (peripheral blood) of patients with oral squa- mous cell carcinoma increased by 1.12 fold (P-value<0.001) compared with healthy individuals. Also, the expression level of miR-494 in samples of oral squamous cell carcinoma infected tissue showed a 1.28-fold increase compared to healthy tissue. Conclusion: The results of this study indicate an increase in the expression level (up-regula- tion) of miR-494 in oral squamous cell carcinoma. This biomarker can be used in screening and early detection of oral squamous cell carcinoma.


2020 ◽  
Author(s):  
Sagheer Ahmed ◽  
Saeed Khan ◽  
Syeda Uzma Naqvi ◽  
Kholood Janjua ◽  
Zaira Zulfiqar ◽  
...  

Abstract Background: There is increasing evidence for the role of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) in carcinogenesis, including oral squamous cell carcinoma (OSCC). Several of these mutagenic substances are cytochrome (CYP)2C9 enzyme substrates.Methods: In this study, we examined the association of CYP2C9*2 and *3 genetic polymorphisms in 58 OSCC patients and 174 healthy, age, and sex-matched controls. Genotyping was done with allele-specific polymerase chain reaction followed by agarose gel electrophoreses, while selected samples were sequenced for confirmation of genotyping.Results: The wild type genotype (CYP2C9*1*1) was observed at 83%, *1*3 at 8%, *1*2 at 5%, *2*2 at 2% and *2*3 at 2% in combined case and control groups. On further analysis, however, our results did not reveal an association of these variants with OSCC samples (Odds ratio: 0.608, 95% Confidence Interval: 0.289 - 1.281, p-value: 0.190). While larger studies are needed to confirm or refute these results, they show a lack of association of CYP2C9*2 and *3 polymorphisms with OSCC in this population.Conclusions: This study demonstrates that the genetic polymorphisms in CYP2C9 genes (CYP2C9*2 and *3) are not causing the risk and are not associated with OSCC. Also, CYP2C9 has no role in the pathogenesis of OSCC in this population of patients.Trial registration: Not applicable.


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