Screening Sensitivity According to Breast Cancer Location.

PURPOSE: To examine the relation between breast cancer location and screening mammogram sensitivity, and assess whether this association is modified by body mass index (BMI) or breast density. METHODS: This study is based on all interval cancers (n = 481) and a random sample of screen-detected cancers (n = 481) diagnosed in Quebec Breast Cancer Screening Program participants in 2007. Film-screening mammograms, diagnostic mammograms, and ultrasound reports (when available) were requested for these cases. The breast cancer was then localised in mediolateral oblique (MLO) and craniocaudal (CC) projections of the breast by 1 experienced radiologist. The association between cancer location and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and sensitivity ratios were obtained by marginal standardisation. RESULTS: A total of 369 screen-detected and 268 interval cancers could be localised in MLO and/or CC projections. The 2-year sensitivity reached 68%. Overall, sensitivity was not statistically associated with location of the cancer. However, sensitivity seems lower in MLO posterior inferior area for women with BMI ≥ 25 kg/m2 compared to sensitivity in central area for women with lower BMI (adjusted sensitivity ratio: 0.58, 95% confidence interval [CI]: 0.17-0.98). Lower sensitivity was also observed in subareolar areas for women with breast density ≥ 50% compared to the central areas for women with lower breast density (for MLO and CC projections, adjusted sensitivity ratio and 95% CI of, respectively, 0.54 [0.13-0.96] and 0.46 [0.01-0.93]). CONCLUSIONS: Screening sensitivity seems lower in MLO posterior inferior area in women with higher BMI and in subareolar areas in women with higher breast density. When interpreting screening mammograms, radiologists need to pay special attention to these areas.

Mammography Clinical Image Quality and the False Positive Rate in a Canadian Breast Cancer Screening Program.

PURPOSE: The study sought to determine if mammography quality is associated with the false positive (FP) rate in the Quebec breast cancer screening program in 2004 and 2005. METHODS: Mammography quality of a random sample of screen-film mammograms was evaluated by an expert radiologist following the criteria of the Canadian Association of Radiologists. For each screening examination, scores ranging from 1 (poor quality) to 5 (excellent quality) were attributed for positioning, compression, contrast, exposure level, sharpness, and artifacts. A final overall quality score (lower or higher) was also given. Poisson regression models with robust estimation of variance and adjusted for potential confounding factors were used to assess associations of mammography quality with the FP rate. RESULTS: Among 1,209 women without cancer, there were 104 (8.6%) FPs. Lower overall mammography quality is associated with an increase in the FP rate (risk ratio [RR], 1.4; 95% confidence interval [CI], 1.0-2.1; P = .07) but this increase was not statistically significant. Artifacts were associated with an increase in the FP rate (RR, 2.1; 95% CI, 1.3-3.3; P = .01) whereas lower quality of exposure level was related to a reduction of the FP rate (RR, 0.4; 95% CI, 0.1-1.0; P = .01). Lower quality scores for all other quality attributes were related to a nonstatistically significant increase in the FP rate of 10%-30%. CONCLUSIONS: Artifacts can have a substantial effect on the FP rate. The effect of overall mammography quality on the FP rate may also be substantial and needs to be clarified.

Clinical Image Quality and Sensitivity in an Organized Mammography Screening Program.

PURPOSE: The study sought to examine the association between clinical image quality of mammograms and screening sensitivity. METHODS: Four radiologists evaluated the clinical image quality of 374 invasive screen-detected cancers and 356 invasive interval breast cancers for which quality evaluation of screening mammograms could be assessed from cancers diagnosed among participants in the Quebec Breast Cancer Screening Program in 2007. Quality evaluation was based on the Canadian Association of Radiologists accreditation criteria, which are similar to those of the American College of Radiology. The association between clinical quality and screening sensitivity was assessed by logistic regression. Adjusted sensitivity and adjusted sensitivity ratios were obtained through marginal standardization. No institutional review board approval was required. RESULTS: A proportion of 28% (206 of 730) of screening mammograms had lower overall quality for the majority of assessments. Positioning was the quality attribute that was the most frequently deficient. The 2-year screening sensitivity reached 68%. Sensitivity of screening was not statistically associated with the overall quality (ratio of 2-year sensitivity = 1.03; 95% confidence interval: 0.93-1.15) or with any quality attributes (positioning, exposure, compression, sharpness, artifacts, contrast). Results were similar for the 1-year sensitivity. CONCLUSIONS: Although not all mammograms in the Quebec screening program met the optimum quality required by the Canadian Association of Radiologists or American College of Radiology accreditation, the screening mammograms produced in this population-based organized screening program reached a high enough level of quality so that the remaining variation in quality is too little to impair screening sensitivity.

Technologists' Characteristics and Quality of Positioning in Daily Practice in a Canadian Breast Cancer Screening Program.

RATIONALE AND OBJECTIVES: This study evaluates to what extent technologists' experience, training, or practice in mammography are associated with screening mammography positioning quality. MATERIALS AND METHODS: Positioning quality of a random sample of 1278 mammograms drawn from the 394,190 screening examinations performed in 2004-2005 in the Breast Cancer Screening Program of Quebec (Canada) was evaluated by an expert radiologist. Information on technologists' experience, training, and practice was obtained by mailed questionnaire. Multivariable Poisson regression models with robust estimation of variance were used to assess the association of technologists' characteristics with higher positioning quality. RESULTS: Of 254 randomly selected technologists, 220 (86.6%) completed the questionnaire. Participating technologists did 89.2% of available sampled mammograms (1088 of 1220), of which 45.9% were of higher positioning quality. Technologists who, in addition to mandatory training, followed at least 15 hours of hands-on training in positioning performed higher positioning quality (adjusted ratio = 1.3, 95%CI = 1.1-1.5) than technologists with no such additional training. Technologists providing at least 15 hours of continued medical education also performed higher positioning quality (adjusted ratio = 1.3, 95%CI = 1.1-1.5) than those who provided less than 15 hours of continued medical education. Being involved in film development and proportion of mammograms performed that are screening compared to diagnostic were also associated with positioning quality, although the latter association was less clear. CONCLUSIONS: Extra hands-on training in positioning could further improve screening mammography positioning quality in the screening program because many technologists did not have such additional training.

Clinical image quality in daily practice of breast cancer mammography screening.

OBJECTIVE: To assess the quality of screening mammograms performed in daily practice in the Quebec Breast Cancer Screening Program. SUBJECTS AND METHODS: Clinical image quality of a random subsample of 197 screening mammograms performed in 2004-2005 was independently evaluated by 2 radiologists based on the criteria by Canadian Association of Radiologists (CAR). When disagreement occurred for overall judgement or positioning score, the mammograms were reviewed by a third radiologist. Cohen's kappas for interrater agreement were computed. Multivariable robust Poisson regression models were used to study associations of overall quality and positioning with body mass index (BMI) and breast density. RESULTS: The CAR criteria were not satisfied for 49.7% of the mammograms. Positioning was the quality attribute most often deficient, with 37.2% of mammograms failing positioning. Interrater agreement ranged from slight (kappa = 0.02 for compression and sharpness) to fair (kappa = 0.30 for exposure). For overall quality, women with a BMI ≥ 30 kg/m(2) had a failure proportion of 67.5% compared with 34.9% for women with a BMI<25 kg/m(2) (risk ratio 2.1 [95% confidence interval, 1.5-3.0]). For positioning, women with a BMI ≥ 30 kg/m(2) had a failure proportion of 53.8% compared with 27.9% for women with a BMI < 25 kg/m(2) (risk ratio 1.9 [95% confidence interval, 1.2-3.1]). Effects of breast density on image quality differed among radiologists. CONCLUSION: Despite measures to ensure high-quality imaging, including CAR accreditation, approximately half of this random sample of screening mammograms failed the CAR quality standards. It would be important to define quality targets for screening mammograms carried out in daily practice to interpret such observations.

Sonographic and mammographic appearances of breast hemangioma.

OBJECTIVE: The purpose of our study was to retrospectively evaluate the clinical, imaging, and pathologic findings of breast hemangiomas in 16 patients. CONCLUSION: A mass displaying an oval or lobular shape with well-circumscribed or microlobulated margins on mammography and sonography, and in a superficial location, should alert the radiologist to the possible diagnosis of hemangioma. Imaging-guided biopsy appears sufficiently reliable to rule out any malignant or premalignant component and to avoid a surgical excision if doing so is clinically appropriate.

Neoadjuvant chemotherapy in invasive breast cancer results in a lower axillary lymph node count.

BACKGROUND: It is essential to have the highest level of confidence in axillary staging assessment. Many surgeons and pathologists believe that fewer lymph nodes are present in axillary dissection specimens of women treated by neoadjuvant chemotherapy. Consequently, the purpose of this study was to compare the lymph node counts of axillary dissection specimens from patients having received neoadjuvant chemotherapy with those of patients treated with primary operation. STUDY DESIGN: A retrospective analysis of a prospective database from our institution identified 283 women with invasive breast cancer who underwent level I and II axillary lymph node dissections. Women from the neoadjuvant chemotherapy group (n=107) were compared with those from the primary surgery group (n=176). The total number of lymph nodes harvested was considered as a continuous variable, but also dichotomized into two categories (< 10 and >or=10). Its correlation with the different variables was analyzed. RESULTS: The median number of lymph nodes retrieved in the neoadjuvant chemotherapy group was 10.0 (range 0 to 38) compared with 12.5 (range 0 to 30) in the control group (p=0.002). There were also significantly more patients with fewer than 10 lymph nodes recovered in the neoadjuvant group (45 versus 28%, p=0.007). Logistic regression showed that neoadjuvant chemotherapy was the only factor associated with retrieval of fewer than 10 lymph nodes. CONCLUSIONS: This study suggests that administration of neoadjuvant chemotherapy to breast cancer patients results in a reduced number of lymph nodes retrieved in the axillary dissection specimens.

Scintigraphic probability and angiographic diagnostic certainty in acute pulmonary embolism.

The objectives of this study were to determine if diagnostic certainty on angiography correlates with scintigraphic probability for the diagnosis of pulmonary embolism. From a total of 160 consecutive patients who underwent both nuclear imaging and invasive selective pulmonary angiography, we reviewed the xenon-133 ventilation images in 2 posterior oblique views and the Tc-99m macroaggregated serum albumin perfusion scans and angiograms of 40 patients (15 men, 25 women; average age 57 years) who were discharged from the hospital on anticoagulants with a diagnosis of pulmonary embolism. The angiograms were reviewed and the diagnosis of embolism was considered certain in the presence of an intraluminal filling defect, a trailing embolus, or a branch occlusion equal to or larger than a segmental branch (n=29; 73%), and uncertain when the studies were reinterpreted as either equivocal or negative or in the presence of a single, small subsegmental filling defect of questionable clinical significance. The ventilation-perfusion scans were read as high (n=18; 45%), intermediate (n=10; 25%), or low (n=12; 30%) probability. The proportion of patients with diagnostic certainty on angiography in the high-, intermediate-, and low-probability scintigraphic subgroups was, respectively, 100% (18 of 18), 70% (7 of 10), and 33% (4 of 12) (P=0.004). In patients diagnosed with pulmonary embolism based on selective angiography, a lower probability of pulmonary embolism on ventilation-perfusion scintigraphy correlates with a lesser degree of diagnostic certainty on angiography and a higher incidence of single subsegmental emboli.