Volume 112, Issue 5 p. 1153-1161
Original Article
Free Access

Determinants of breast cancer knowledge among newly diagnosed, low-income, medically underserved women with breast cancer

Judy Y. Chen MD, MSHS

Judy Y. Chen MD, MSHS

Health Benchmarks, Inc., Woodland Hills, California

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Allison L. Diamant MD, MSHS

Allison L. Diamant MD, MSHS

Department of Medicine, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California

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Amardeep Thind MD, PhD

Amardeep Thind MD, PhD

Department of Family Medicine, University of Western Ontario, London, Ontario, Canada

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Rose C. Maly MD, MSPH

Corresponding Author

Rose C. Maly MD, MSPH

Department of Family Medicine, David Geffen School of Medicine at University of California-Los Angeles, Los Angeles, California

Fax: (310) 794-6097

Department of Family Medicine, David Geffen School of Medicine at the University of California-Los Angeles, 10880 Wilshire Boulevard, Suite 1800, Los Angeles, CA 90095-7087===Search for more papers by this author
First published: 11 January 2008
Citations: 66



Among women with breast cancer (BC), greater BC knowledge has been associated with greater participation in treatment decision-making, patient satisfaction, and survival. The objective of this study was to identify modifiable determinants associated with BC knowledge.


Data were collected from a telephone survey of medically underserved women with BC in California (n = 909). The dependent variable for analysis was BC knowledge. The modifiable determinants that were assessed included 1) physician-patient discussion of BC topics, 2) receipt of written BC-related material, 3) self-efficacy in interacting with physicians, 4) physician emotional support, 5) discussions with a BC survivor, and 6) office visit support by relatives/friends. Multivariate linear regression was used to examine the effect of those determinants on BC knowledge while controlling for socioeconomic factors, clinical characteristics, and treatment received.


The average knowledge score was 6.9 (standard deviation, 2.3; range, 0–10). In multivariate analyses among women with less physician emotional support, those with the greatest self-efficacy had higher knowledge scores than those with the least self-efficacy (8.2 vs 5.4; P < .001). For women with low self-efficacy, those with more physician emotional support had higher knowledge scores than those with less physician emotional support when the analysis was controlled for confounding factors (6.3 vs 5.4; P < .001); physician information-giving had no effect on BC knowledge.


The study findings suggested significant associations of patient self-efficacy and physician emotional support with BC knowledge; physician emotional support appeared to be more important than physician informational support. Further research will be needed to investigate whether interventions that target these 2 domains may be effective in increasing BC knowledge in disadvantaged populations. Cancer 2008. © 2008 American Cancer Society.

Having more health knowledge can have an important and positive impact on overall survival and quality of life in many disease processes. Individuals who are knowledgeable regarding the benefits of nutrition and exercise are more likely to lead healthy lifestyles,1, 2 and individuals who are knowledgeable about preventive services, disease symptoms, and health risks are more likely to be diagnosed early and to receive appropriate treatment.3-6 Increasing patients' knowledge enhances their ability to participate actively in the decision-making process for medical care and to manage their medical conditions better, which can lead to improved clinical outcomes, better quality of life, and decreased morbidity and mortality.7-16

Among women with breast cancer, greater knowledge of treatment options has been associated with more involvement in the decision-making process for primary breast cancer treatment, better functional and physical well-being, and greater patient satisfaction.17, 18 Women must rely on their knowledge of treatment options when making decisions for primary breast cancer treatment. Study findings indicate that patients who knew that cancer survival did not differ between breast-conserving surgery (BCS) and mastectomy were more likely to choose the former, whereas women who knew that BCS was associated with a greater risk of local tumor recurrence than mastectomy were more likely to choose the latter.19, 20 The extent of patients' knowledge also may influence outcomes: Goodwin et al. observed that higher levels of cancer knowledge were associated with greater cancer survival.21

Knowledge of breast cancer and its treatment is generally low among women who have been diagnosed with breast cancer.19, 20, 22 African-American women and women with less education are less likely to be knowledgeable about breast cancer treatment than white women and more educated women, after controlling for age and stage.19 In addition, study findings demonstrate that breast cancer knowledge is greater for women who access the Internet and read health pamphlets19 and for those women who discuss a greater number of breast cancer topics with their physician.23 These studies were somewhat limited, because assessments of knowledge were restricted to only 1 or 2 knowledge items. Furthermore, there is a paucity of information about the determinants of lower breast cancer knowledge among low-income, medically underserved women. These women may be at particular risk for lower knowledge levels because of a lack of resources and lower educational levels with concomitantly lower health literacy, which could jeopardize appropriate treatment decision-making and other important outcomes, as noted above.

The objective of this study was to identify modifiable characteristics associated with lower breast cancer knowledge among low-income, medically underserved women who are diagnosed with breast cancer. Specifically, we focused on aspects of patient-physician interactions, interactions with other breast cancer patients, and office visit support (ie, accompaniment by friends or relatives), all of which are potential conduits for elicitation and/or transfer of information. Identifying mutable factors associated with lower breast cancer knowledge among these women can provide the empirical basis for developing intervention strategies to increase patients' cancer knowledge and potentially may improve outcomes among vulnerable populations.


Our study population consisted of English- or Spanish-speaking women with newly diagnosed breast cancer (diagnosed 6 months before recruitment) who were enrolled in the Medi-Cal (California's Medicaid) Breast and Cervical Cancer Treatment Program (BCCTP). Women who were not able to participate cognitively, did not speak English or Spanish, or were receiving treatment for another nonbreast cancer were excluded from this study. The BCCTP is a relatively new coverage option that was legislated by the federal government as part of the Breast and Cervical Cancer Prevention and Treatment Act of 2000 and is funded through Medicaid. BCCTP provides coverage to uninsured and under-insured, low-income women (<200% Federal Poverty Level) who are diagnosed with breast and cervical cancer and require cancer treatment.

Potential participants were identified through partnership with the California Department of Health Services from March 2004 through September 2005 and were invited to complete a 1-hour baseline telephone survey in either English or Spanish. Of 1869 women who were mailed a written invitation to participate in the survey, 161 refused further contact (Fig. 1). The research team contacted 1709 women by telephone who did not refuse to participate by mail. Of these women, 361 were ineligible for the study, 78 refused to participate, and 234 could not be contacted. Nine hundred twenty-one of 1508 eligible women who agreed to participate completed the baseline telephone interview, yielding a final response rate of 61.1%.

Details are in the caption following the image

Study recruitment flow.

The baseline survey was conducted a mean of 180 days (standard deviation [SD], 20.8 days) after women received a definitive diagnosis of breast cancer. Nonresponders were older than responders by 2 years (mean age, 52 years vs 50 years, respectively; P < .05) and were more likely to be white (32% vs 30%; P < .05). For these analyses, we excluded women with self-reported metastatic disease (n = 12), because their treatment options may be more limited than women without metastasis. Thus, the final sample size was 909 women.

The dependent variable was breast cancer knowledge, which was measured by 10 true-or-false questions (range, 0–10) from which we calculated the mean number of correct responses (Table 1).24 We divided the modifiable, independent variables into 3 domains: patient-physician interactions, interaction with other breast cancer patients, and office visit support. Patient-physician interactions were measured in the following ways: 1) physician-patient verbal discussion of 16 breast cancer topics, such as treatment choices and risk for recurrence, as assessed by a previously developed index25; 2) receipt of written material about breast cancer in the patient's primary language; 3) perceived patient self-efficacy in patient-physician interactions; and 4) perceived emotional support provided by physicians. We assessed physician-patient discussions and receipt of written materials, because, in prior studies, patients who had more discussions with their physicians23, 26 and who read books or pamphlets about breast cancer19 demonstrated greater knowledge about their cancer. Patients' perceived self-efficacy in patient-physician interactions was measured, because evidence exists that greater self-efficacy is associated with significantly higher cancer screening knowledge.4 Self-efficacy was assessed by using the previously validated Perceived Efficacy in Patient-Physician Interactions Questionnaire (PEPPI).27 This instrument consists of 5 items that describe patients' confidence in their ability to communicate with their physicians and obtain needed attention to their chief medical concerns. The PEPPI scale ranges from 0 to 50, with higher scores corresponding to higher perceived self-efficacy in patient-physician interactions. The internal consistency reliability (Cronbach α28) for this scale was .95. We divided the PEPPI scale into quartiles because of its skewed distribution in this sample.

Table 1. Breast Cancer Knowledge*
Breast cancer knowledge questions (true/false) Correct answer % Correct
1. Mastectomy means removing the whole breast True 99
2. Even when breast cancer is found early, an individual's chance of survival is not very good False 97
3. In the early stages of breast cancer, cancer cells may be present in all parts of the body True 62
4. Lumpectomy means removing only the cancerous lump and not the whole breast True 99
5. Radiation therapy usually follows lumpectomy True 74
6. Radiation therapy generally lasts no more than 1–2 weeks False 98
7. After radiation therapy, your hair may fall out False 93
8. Tamoxifen/Novadex/Arimidex/Femora or chemotherapy may be needed to kill cancer cells that are left after surgery True 96
9. Both lumpectomy with radiation and mastectomy offer the same chance for survival True 81
10. Lumpectomy with radiation is the quicker form of treatment compared with mastectomy False 64
  • * Average knowledge score = 6.9 (standard deviation = 2.3).
  • Percentage of women who answered the question correctly.

We measured patient-perceived emotional support by physicians to explore our hypothesis that patients would be more likely to elicit, register, and retain information necessary to their medical care in a more nurturing environment. Perceived emotional support was measured by asking, “How often did your doctors 1) allow you to express all of your feelings, 2) show extreme compassion and caring, and 3) listen very carefully to you?” It is worth noting that participants were directed to answer with regard to their “breast cancer doctors” and not with regard to any specific specialty within that category of physicians. Patients answered these 3 questions on a 4-point scale (Cronbach α = .91). Because of the skewed distribution, these questions were then collapsed into a single, dichotomous variable: Respondents who had scores greater than or equal to the median were coded as having more physician emotional support, and respondents who had scores less than the median were coded having less physician emotional support.

Because other cancer patients may provide valuable insights into the cancer treatment process, we assessed whether the respondent had breast cancer-related discussions with another breast cancer patient (yes/no). In addition, we measured office visit support, because friends and relatives who accompany patients during the office visit may help the patient to solicit and retain information necessary for treatment decision-making. Office visit support was measured by asking whether a friend or relative always or usually versus sometimes or never accompanied the respondents during their visits with their physician.

Other independent variables that were assessed included age, self-reported race/ethnicity incorporating language (white, African American, Latina who completed the survey in Spanish, Latina who completed the survey in English, Asian American, and other), education (high school graduate or less, some college, college graduate or more), regular source of care before cancer diagnosis (yes/no), and marital/partner status. We divided Latinas according to the language that was used to conduct the telephone survey to further assess the impact of English fluency on breast cancer knowledge. We also assessed clinical characteristics, including comorbidity and general health status. General health status was assessed by asking the question “In general, would you say your health is: excellent, very good, good, fair, or poor?,” with a general health measure that was taken from the 36-item Short-Form Health Survey29 and was dichotomized to excellent, very good, or good versus fair or poor. Comorbidity was assessed by patient self-report using the Katz et al. adaptation of the Charlson Comorbidity Index for self report,30 and was dichotomized as any versus none. Because of the retrospective nature of this study, women who had experienced multiple types of treatment at the time of the baseline survey would be more likely to have more breast cancer treatment knowledge. Therefore, we included procedures (lumpectomy, mastectomy, radiation therapy, and chemotherapy) to control for the effect of individual treatment types on breast cancer knowledge.

Statistical Analysis

First, we performed univariate, descriptive, statistical analyses and bivariate analyses to assess the associations between dependent and independent variables. Second, multivariate linear regression was used to examine the effect of patient-physician interactions, interaction with other breast cancer patients, and office visit support on breast cancer treatment knowledge scores while controlling for socioeconomic factors, clinical characteristics, and procedure received. Third, the model was tested for all significant interaction terms that involved modifiable determinants, and the interaction term “physician emotional support*self-efficacy” was identified as statistically significant. In the final multivariate linear regression model, we included the interaction of physician emotional support and self-efficacy. For ease of interpretation of the interaction term (physician emotional support*self-efficacy), we calculated the predicted values of knowledge scores by using the model parameters and the mean value for each predictor except the characteristics of interest (Table 2). For example, the predicted knowledge score of women who had more physician emotional support and who had self-efficacy in the highest quartile was calculated by recoding every observation as having more physician emotional support and self-efficacy in the highest quartile while holding all other independent variables at the mean. The 95% confidence intervals for the predicted values were calculated with the δ method using the prvalue command in STATA. Because of multiple testing, 2-sided α levels of P values < .01 were used to determine statistical significance.

Table 2. Predicted Knowledge Scores (95% Confidence Intervals) From Multivariate Linear Regression*
Variable Self-efficacy: predicted knowledge scores (95% CI)
First quartile: lowest Second quartile Third quartile Fourth quartile: highest
More physician emotional support 6.3 (5.9–6.7) 6.7 (6.5–7) 7.1 (7–7.4) 7.6 (7.4–7.9)
Less physician emotional support 5.4 (5.1–5.8) 6.4 (6.1–6.6) 7.3 (7–7.6) 8.2 (7.7–8.7)
  • 95% CI indicates 95% confidence interval.
  • * Multivariate linear regression model: Knowledge score = function (age, race, education, income, marital status, regular source of care, general health status, comorbidity, lumpectomy, radiation therapy, visit support, received written cancer information, talked to another cancer patient, physician-patient verbal discussions, physician emotional support, self-efficacy, and physician emotional support self-efficacy).


Descriptive statistics for our cohort (n = 909) are provided in Table 3. The mean age of the sample was 51 years (SD, 9.3 years). Spanish-speaking Latinas made up the majority of respondents (48%) followed by English-speaking Latinas (6%), white women (31%), African-American women (6%), Asian-American women (5%), and women from “other” backgrounds (4%). Forty-three percent of the women had not graduated from high school, and 40% had some college education. Fifty percent of respondents were married or partnered, and approximately 66% had a regular source of care before they were diagnosed with breast cancer. More women rated their general health status as excellent, very good, or good (68%) than fair or poor (32%), and 70% had no prior comorbidity. Over half of women had undergone a lumpectomy (52%), 39% had undergone a mastectomy, 29% had received radiation therapy, and 58% had received chemotherapy.

Table 3. Descriptive Statistics
Variable Percentage of cohort, n = 909
Sociodemographic characteristics
 Mean age ± SD, y 51 ± 9.3
  White 31
  African American 6
  Spanish-speaking Latina 48
  English-speaking Latina 6
  Asian American 5
  Other 4
  <High school 43
  High school graduate 17
  ≥College 40
 Married 49
 Regular source of care (yes) 60
Clinical characteristics
 General health status
  Excellent, very good or good 68
  Fair or poor 32
 No prior comorbidity 70
 Lumpectomy 52
 Mastectomy 39
 Radiation therapy 29
 Chemotherapy 58
Modifiable determinants
 No. of physician-patient verbal discussions of breast cancer topics, mean ± SD* 9.4 ± 3.5
 Received written cancer information in primary language 85
 Talked to another breast cancer patient 78
 Received more emotional support from physicians 64
 Someone usually or always accompanied patient at medical appointments 47
  • SD indicates standard deviation.
  • * The following physician-patient verbal discussions per patient self-report were tallied: 1) rapidity of tumor growth, 2) probability of cancer recurrence, 3) possibility of removing lymph nodes, 4) 2 choices of surgery—lumpectomy vs mastectomy, 5) breast reconstruction, 6) adjuvant therapy, 7) what to expect during treatment, 8) possible causes of breast cancer, 9) need for chemotherapy, 10) need for hormone therapy, 11) need for radiation therapy, 12) postoperative wound care, 13) body image after treatment, 14) side effects of lymph node surgery, 15) extensiveness of cancer spread, and 16) urgency of need for treatment.

According to patient reports, the mean number of breast cancer topics that were discussed verbally with a physician was 9.4 (out of 16 possible topics). Furthermore, the majority of respondents reported that they received written breast cancer information either in booklets or pamphlets (85%), talked to another breast cancer patient (78%), and received more emotional support from their physicians (64%). Slightly less than half of respondents (47%) reported that someone always or usually accompanied them to medical appointments.

On average, women answered 7 of 10 true-or-false breast cancer knowledge questions correctly (Table 1). Virtually all women were able to answer questions regarding the definition of mastectomy and lumpectomy (99%). Only 62% of women knew that, in the early stages of breast cancer, cancer cells may be present in all parts of the body, and only 64% knew that lumpectomy with radiation is not the quicker form of treatment, whereas 74% knew that radiation therapy should follow lumpectomy.

In the multivariate linear regression analysis, self-efficacy, and physician emotional support were the only significant modifiable determinants of breast cancer knowledge (Table 4). The adjusted correlation coefficient (R2) for this model was 0.35 (P < .0001). The effects of self-efficacy and physician emotional support on breast cancer knowledge scores are displayed in Table 2. Women who had higher perceived self-efficacy in patient-physician interactions had higher knowledge scores overall compared with women who had lower perceived self-efficacy. Having more physician emotional support was of greatest benefit to women in the lowest self-efficacy quartile (predicted knowledge score: 6.3 for women with physician emotional support vs 5.4 for women without physician emotional support). For women in the highest quartile of self-efficacy, having more physician emotional support did not translate into higher knowledge scores (predicted knowledge score: 7.6 for women with more physician emotional support vs 8.2 for women with less physician emotional support). Other significant predictors of lower breast cancer knowledge scores were ethnicity and language (Spanish-speaking Latinas answered fewer knowledge questions correctly), less than high school graduate, and no radiation therapy (Table 4).

Table 4. Multiple Linear Analysis of Patient Breast Cancer Treatment Knowledge
Determinants Coefficient SE P
Modifiable determinants
 Someone usually or always accompanied patient at medical appointments* −0.01 0.14 .932
 Received written cancer information in primary language −0.09 0.19 .626
 Talked to another breast cancer patient 0.25 0.16 .119
 More physician emotional support§ 1.39 0.36 .000
 Physician-patient verbal discussions of breast cancer topics 0.03 0.03 .191
 Self-efficacy in interacting with physicians 0.92 0.11 .000
 Physician emotional support * self-efficacy interaction term −0.50 0.14 .000
Nonmodifiable control variables#
 Age −0.02 0.01 .029
 Race (white)
  African American −0.16 0.30 .603
  Spanish-speaking Latina −0.96 0.20 .000
  English-speaking Latina −0.48 0.30 .107
  Asian American −0.75 0.32 .019
  Other race −0.87 0.34 .019
 Education (≥college)
  <High school −0.99 0.18 .000
  High school graduate −0.47 0.20 .010
 Married (not married) −0.16 0.16 .318
 Regular source of care (no) −0.07 0.14 .628
 General health status (excellent, very good, or good)
  Fair or poor −0.21 0.19 .094
 No comorbidity (have comorbidity) −0.06 0.15 .686
 Lumpectomy (no lumpectomy) 0.12 0.14 .337
 Mastectomy (no mastectomy) −0.01 0.19 .943
 Radiation therapy (no radiation) 0.72 0.16 .000
 Chemotherapy (no chemotherapy) 0.00 0.14 .980
  • SE indicates standard error.
  • * The reference group is “someone sometimes or rarely accompanies patient to medical appointments.”
  • The reference group is “did not receive written material in primary language.”
  • The reference group is “did not talk to another breast cancer patient.”
  • § The reference group is “less emotional support by physicians.”
  • Considered a significant predictor in this study (P < .01).
  • Physician emotional support × self-efficacy interaction term.
  • # The reference group for the categorical control variables is in parentheses.


Overall, the results from this study demonstrated that, in an at-risk, low-income population of women with breast cancer, greater self-efficacy in interacting with physicians and physicians' emotional support of patients were powerful predictors of breast cancer knowledge, whereas quantity of information-giving, written or verbal, had no impact. These findings are in contradistinction to research that has demonstrated no effects of these 2 variables on breast cancer knowledge in a general population of newly diagnosed women, although physician information-giving was a positive predictor when controlling for confounding factors.25 Our current results suggest that low-income, medically underserved women are served better by psychosocial, attitudinal aspects of the patient-physician relationship than by concrete physician communication behavior in overcoming the disadvantages of their socioeconomic status and achieving levels of knowledge that may facilitate other important outcomes of care, from patient involvement in decision-making17, 18 to survival.21 In addition, it appears that having more physician emotional support positively affected knowledge scores, particularly among women with lower self-efficacy. This finding in a subgroup that apparently manifested greater disempowerment than even other low-income women further underscores the important influence of emotional supportiveness. In the setting of low socioeconomic status, an empathetic and nurturing environment provided by physicians may be especially required for patients to elicit, register, and retain information necessary to their medical care.

To date, interventions to improve patient knowledge and facilitate patient decision-making in breast cancer have been provider-centered with the objective of improving the provider's ability to present material and communicate with patients.31, 32 In contrast, we observed that the quantity of physician information given—both verbal and written—was not associated significantly with higher breast cancer knowledge in low-income, medically underserved women when controlling for self-efficacy and physician emotional support. Findings from this study suggest that training providers to support the emotional needs of patients may be especially effective among patients who have less confidence in their ability to interact with their physicians to improve their cancer knowledge. In addition, patient-centered interventions to increase self-efficacy may be needed. At least 1 study among patients with chronic medical conditions has demonstrated that simple patient-centered interventions to increase patients' confidence in interacting with physicians before medical consultations can improve self-reported health status, physical functioning, and satisfaction.33

Despite controlling for aspects of the physician-patient interaction, we identified 2 groups of women who had significantly less knowledge about breast cancer and its treatment: minority women of limited English proficiency (Spanish-speaking Latinas) and women who had not graduated from high school. Our findings of lower levels of breast cancer treatment knowledge among minority women and less educated women are supported by results from other studies.19, 23 In addition, patients who experience language discordance with their health care provider appear to be at elevated risk for receiving limited counseling from their physicians.34 This finding emphasizes that interventions to increase cancer knowledge need to be appropriate linguistically and comprehensible to women with lower educational levels.

Strengths of this study include large, statewide sampling of a defined, medically underserved population of women with newly diagnosed breast cancer, allowing a close examination of factors pertinent to breast cancer knowledge in a highly understudied group particularly at risk for adverse outcomes. However, our findings should be considered in light of several limitations. First, because all of the study participants were of low income, comparisons with populations of greater means and resources could not be made; the generalizability of our findings to a broad spectrum of income groups needs further study. Second, because the survey was conducted only in English and Spanish, Asian Americans identified in this study were not representative of all Asian Americans in the United States, many of whom may not be fluent in either of these 2 languages. Third, this was a cross-sectional study, and causal relations between self-efficacy, patient-physician communication, and other modifiable factors and knowledge cannot be established. Finally, because the majority of knowledge questions focused on breast cancer treatment, it is possible that some women may have had lower treatment knowledge scores because of ineligibility for certain types of treatment.

In conclusion, in this study, we observed that increased patient self-efficacy in interacting with physicians and having more physician emotional support were associated with greater breast cancer treatment knowledge in a low-income, medically underserved population, even when controlling for the quantity of physician information-giving and education. In fact, information-giving did not appear to be effective in increasing knowledge in these low-income, medically underserved women, in contrast to previous research in a general population.23 Compared with women who have greater means, this vulnerable group necessarily faces additional strain and life burden imposed by fewer resources when facing an already stressful diagnosis of cancer. Consequently, it is possible that this population requires a particularly emotionally supportive and empowering environment to overcome the confounding and additive adverse effects of deprivation on transfer of information. In addition, 2 groups were at particular risk for lower breast cancer knowledge: Spanish-speaking Latinas and women with limited education. All of these findings suggest that linguistically appropriate, patient-centered intervention strategies to increase women's self-efficacy in interacting with physicians and provider-centered interventions to train physicians to support the emotional needs of their patients may be effective in increasing breast cancer treatment knowledge and should be tested among these higher risk groups. If successful, such interventions have the potential for positively influencing participatory decision-making, treatment adherence, quality of life, and survival in disadvantaged populations.1, 2, 5, 7, 8, 10, 11, 21