|Year : 2014 | Volume
| Issue : 2 | Page : 129-133
Study of cognitive functions in breast cancer patients: A case control study
Anupama Zeena Sequeira1, K Krishnamurthy2
1 Post Doctoral Fellow in Child and Adolescent Psychiatry Unit, Department of Psychiatry, Christian Medical College, Vellore, Tamil Nadu, India
2 Head of Department of Psychiatry, Narayana Medical College and Hospital, Nellore, Andhra Pradesh, India
|Date of Web Publication||1-Jul-2014|
Anupama Zeena Sequeira
White Manor, Opp Panchmal Plastic Ind, Shaktinagar PO, Kulshekar, Mangalore - 575 016, Karnataka
Source of Support: None, Conflict of Interest: None
Context: One-third of breast cancer survivors report difficulties with concentration, multi-tasking, and memory. Cognitive dysfunction can have an impact on quality of life by affecting activities of daily living, treatment compliance, interpersonal relationships, work/profession, and future. Aims: The objective of this study was to evaluate the cognitive functions in breast cancer patients. Settings and Design: This study was conducted in the outpatient department of Oncology from where the cases were recruited. The controls were patients attending other departments and not suffering from cancer. Materials and Methods: A total of 60 patients, 30 breast cancer patients and 30 non-cancer individuals patients matched for age, education were evaluated. Tools used were SMMSE, TMT-B, and DSST for evaluation of cognitive functions. Statistical Analysis: The various findings were analyzed using Chi-square test, Mann-Whitney Test, T test and ANOVA. Results: Breast cancer patients had highly statistically significant cognitive deficits in language and recall domains and significant deficit on orientation domain of SMMSE. They performed poorly in TMT-B, taking more time to complete the test which was statistically highly significant. No significant deficits were noted on the DSST test. Conclusion: Breast cancer patients show statistically significant cognitive deficits as compared to non cancer individuals.
Keywords: Breast cancer, cancer, cognition
|How to cite this article:|
Sequeira AZ, Krishnamurthy K. Study of cognitive functions in breast cancer patients: A case control study. Muller J Med Sci Res 2014;5:129-33
|How to cite this URL:|
Sequeira AZ, Krishnamurthy K. Study of cognitive functions in breast cancer patients: A case control study. Muller J Med Sci Res [serial online] 2014 [cited 2019 Oct 16];5:129-33. Available from: http://www.mjmsr.net/text.asp?2014/5/2/129/135745
| Introduction|| |
Cognitive dysfunctions have been reported in various medical disorders like diabetes, HIV infection, hypertension, renal impairment, congestive cardiac failure and epilepsy. People with cancer may experience difficulty with thinking ability, including memory loss, distractibility, difficulty in performing multiple tasks (multitasking), and trouble with arithmetic and language skills. The causes of cognitive dysfunction are many, including the direct effects of cancer on the CNS, indirect effects of certain cancers or effects of cancer treatment on the brain or the diagnosis of cancer by itself can produce emotional disturbance to a great extent which can influence cognitive function as well as bear influence on the quality of life itself. 
Since the 1980's, women treated for breast cancer are reporting moderate cognitive impairments during and after chemotherapy. These cognitive impairments may also be due to hormone therapy, psychological distress and fatigue. Up to one-third of women breast cancer survivors report difficulties with concentration, multi-tasking, and memory and these cognitive difficulties are associated with poorer quality of life among breast cancer survivors after treatment. Cognitive dysfunction can have an impact on quality of life by affecting activities of daily living, interpersonal relationships, work/ profession, and future. , As per studies done previously, before the systemic therapy- learning and memory function were impaired significantly more frequently relative to normative expectations.  Neuropsychological testing after chemotherapy has shown dysfunction related to attention, learning, and processing speed. 
Following hormonal therapy processing speed and verbal memory were the cognitive domains most affected. 
Indian studies on the cognitive dysfunction in breast cancer patients are lacking. Hence this study is designed to evaluate the cognitive functions and the factors influencing it in diagnosed breast cancer patients without taking into consideration their treatment status.
| Aims|| |
- To evaluate the cognitive functions in diagnosed breast cancer patients.
- To compare the cognitive functions with controls matched for age and socio-economic status.
| Materials and Methods|| |
This is a cross-sectional case-control study involving administration of a battery of neuropsychological tests to assess the cognitive functions in patient group and control group which have been matched for age and socio-economic status.
Individuals who fulfilled the inclusion and exclusion criteria (which are stated below) were selected by purposive sampling technique. Thirty patients with diagnosed breast cancer attending the oncology department at Fr Muller Medical College which is a tertiary care hospital, and 30 controls matched with respect to age and socio-economic status, not suffering from cancer and attending the other departments at this hospital were interviewed using a semi-structured proforma and data was collected. The study was conducted over a period of 1 year beginning from March 2009. A written informed consent was obtained from all patients, who were, prior to consent, informed that refusal to participate would not alter the course of treatment nor would affect the outcome. Ethical clearance was sought prior to undertaking the study.
Inclusion and Exclusion Criteria
Inclusion criteria for cases
- Individuals diagnosed with breast cancer in the oncology department of FMMC.
- Age: 20-60 years of female sex.
- Educated above primary school level.
- Individuals who have given written informed consent.
Inclusion criteria for controls
- Individuals attending other departments of the hospital who are willing to participate in the study and have no family history of cancer in first degree relatives.
- Age: 20-60 years of female sex.
- Matched for age and socio-economic status to the subject sample.
- Educated above primary school level.
- Individuals who have given written informed consent.
Exclusion criteria for both groups
- Individuals suffering from any neuropsychiatric, major medical/ chronic neurological illness which would affect cognitive functions.
- Individuals with substance abuse/dependence disorder.
- Individuals suffering from any sensory impairment that is visual or hearing impairment or learning disability which may serve as a hindrance in performing the tests.
- Individuals who are on long-term corticosteroid therapy.
Instruments for Assessment of Cognitive Functions
The following tests were used based on their ability to accurately detect cognitive impairments in domains reported by earlier studies. 
Standardized mini mental status examination (SMMSE).
Trail making test B (TMT-B).
Digit symbol substitution test (DSST).
The various findings were analyzed using Chi-square test, Mann-Whitney Test, T test and ANOVA.
| Results|| |
In the present study, all the socio-demographic data except for domicile (P = 0.043), was matched for cases and controls [Table 1]. A scale was also administered to assess the participant's socioeconomic status. 
This study has revealed that there is statistically significant cognitive impairment in breast cancer patients as compared to non-cancer individuals [Table 2]. On MMSE, the difference between the two groups is highly significant. There is a highly significant difference in the mean domain scores with respect to recall and language and a significant difference in the domain of orientation. There was significant difference between the cases (mean = 375.17s) and control (mean = 294.17s) group in the mean time taken to complete the trail making test. As per normative data described, in the age group 55-74 years, impairment corresponded to below 2 nd percentile (<154s). 
|Table 2: SMMSE total score, TMT B- total time taken, DSST- total time taken|
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In the trail making test, most of the cases made a single error (80%), likewise among the control group also, single errors were committed by (63.6%) most of the individuals. There was no statistically significant difference between cases and control group seen. Data analysis revealed no significant difference between the control group (mean = 561.17s) and the cases (mean = 534.17s) in the mean time taken to complete the digit symbol substitution test or the number of errors committed. The norms described for 31-50 years, school educated females show impairment below 500s which corresponds to 15 th percentile. 
Staging of breast cancer, as done by the oncologist was also recorded [Table 3]. There was significant difference between early (stages I and II) and late (stages III and IV) breast cancer only in DSST time taken (t = 2.454; P = 0.021) and DSST errors (t = 4.025; P = 0.028). No statistical significant difference was noted on SMMSE and TMT B tests. Cognitive functioning was compared among patients treated with chemotherapy and other forms of treatment and no significant difference was noted among the groups. When duration of illness was compared with cognitive functions, no statistical significance was noted on SMMSE, TMT B and DSST measures between cases with duration less than 1 year and above 1 year. Results indicate no relation of duration of illness and cognitive dysfunction.
| Discussion|| |
The cases and controls were well matched except for the domicile which could be because the controls for the study were bystanders of medical ward patients who were mostly residing in the semiurban areas surrounding the hospital.
The current study shows deficits in recall, language, attention, executive function, visuospatial functions in the breast cancer subjects, which are consistent with earlier studies. ,, Orientation domain has not been recorded to be affected in previous studies and is new finding in this study.
Most studies have used extensive neuropsychological batteries for cognitive testing and have shown fairly global impairments, more so in memory, language, verbal memory, and psychomotor functioning domains. 
One study has shown that Stages 1-3 patients were significantly more likely to be classified as having lower than expected overall cognitive performance as compared to Stage 0 patients and healthy controls.  However, in this study no such difference has been noted between early and late stages which could be due to the smaller sample size.
Most of the studies done previously have noted cognitive dysfunction in patients treated with chemotherapy. ,,,,, Our study did not find statistically significant difference between the chemotherapy treated group and the others. Two of the studies have agreed with these findings. , The findings of this study could be explained on the basis of smaller sample size as well as the other group getting some different modality of treatment like radiotherapy, hormonal therapy which could have also affected their cognitive functioning.
Previous studies have not studied the relationship between duration of malignancy and cognitive functioning. This study did not find any relation between cognitive functioning and duration of malignancy.
Limitations of the Study
- Sample size is small consisting only of 30 breast cancer patients and 30 non-cancer individuals.
- Most of the patients studied have low education (less than 10 years of formal education) which may have affected the findings of the study.
- This study is a cross-sectional study. A longitudinal study would enable to determine stability of the cognitive deficits.
- All domains of cognitive functioning have not been assessed.
- Correlation between all treatment factors and cognitive functions has not been evaluated.
| Conclusion|| |
- The study showed significant differences between cases and controls in recall, language and orientation domains of SMMSE.
- Cases performed significantly worse than controls in time taken to complete the TMT-B test.
This study has proven that cognitive dysfunction can occur in breast cancer patients. Hence a screening and detection of cognitive dysfunction is warranted in this group along with early intervention and management of the same to improve the quality of life.
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[Table 1], [Table 2], [Table 3]