Breast screening: Axillary lymph node status of interval cancers by interval year

Five-year annual incidence and clinico-molecular features of breast cancer after the last negative screening mammography at age 68-69

OBJECTIVE

The European Commission Initiative on Breast Cancer recommendation for triennial screening of women aged 70-74 is based on very weak evidence. A cohort of Italian women who had their last biennial screening mammography at age 68-69 was followed up for 5 years, assumed to represent the interval to another hypothetical screening mammography, in order to determine the annual proportional incidence of interval breast cancer.

METHODS

The cohort included 118,370 women. They had their last mammography between 1997 and 2008. Incident breast cancers were identified by record-linking the cohort with the regional breast cancer registry. The expected incidence in the age range 65-74 was estimated with an age-period-cohort model. The number of interval cancers was divided by the expected number to obtain their proportional incidence.

RESULTS

Overall, there were 298,658 woman-years at risk with 371 interval cancers versus 988.8 expected. In the first, second, third, fourth, and fifth interval year, the proportional incidence was 0.09 (95% confidence interval, 0.06-0.13), 0.32 (0.25-0.39), 0.60 (0.49-0.73), 0.75 (0.60-0.92), and 0.81 (0.60-1.07), respectively. Between the second and the fifth year, tumour stage and molecular subtype did not change significantly.

CONCLUSION

Though not supported by these findings, the proposal of triennial screening for women aged 70-74 merits further research, because the 95% confidence interval of the third-year proportional incidence of interval cancer included 0.50-the maximum limit considered acceptable for women aged 50-69.

KEY POINTS

• The third-year incidence of breast cancer relative to the expected one was 0.60 (95% confidence interval, 0.49-0.73). • Between the second and the fifth year, tumour stage and molecular subtype did not change significantly (p >0.10). • The proposal of a 3-year screening interval at age 70-74 merits further evaluation.

Clinicopathological differences between interval and screen-detected breast cancers diagnosed within a screening programme in Northern Portugal

Objective

To evaluate clinicopathological differences between screen-detected (SD) and interval (IC) breast cancers diagnosed in women enrolled in an organized breast screening programme in 2000--2007.

Setting

Breast Cancer Screening Programme of the north region of Portugal.

Methods

Using data from the screening programme and from the population-based North Region Cancer Registry, SD and IC were identified. Information on screening history, age, date of diagnosis, tumour size, histological type and grade, lymph node status, tumour stage, biomarkers, and treatment was obtained from the cancer registry and from clinical and pathological reports. Association between mode of detection and these clinicopathological characteristics was estimated by unconditional logistic regression.

Results

A total of 442 SD and 112 IC were identified in women aged 50--69. Compared with SD, IC were diagnosed in younger women (60.0 ± 5.8 years and 58.4 ± 6.0 years, respectively), were larger (tumour size >20 mm: 60.2% versus 25.1%), lobular (6.3% versus 16.1%), with a higher differentiation grade (grade 3: 17.7% versus 38.9%), had more lymph node metastases, more advanced stage, and oestrogen receptor (ER) negative (12.9% versus 29.0%) and progesterone negative, and HER2 positive. After multivariable analysis, compared with SD, IC were more likely to be larger than 20 mm, lobular, of grade 3 and negative for ER.

Conclusion

Our results are consistent with other studies. IC’s have a more aggressive biology than SDs. Our findings did not show any unexpected pattern requiring changes to our screening procedures, but continuous identification and characterization of IC is advisable.

Incidence, detection, and tumour stage of breast cancer in a cohort of Italian women with negative screening mammography report recommending early (short-interval) rescreen

BACKGROUND

Although poorly described in the literature, the practice of early (short-interval) rescreen after a negative screening mammogram is controversial due to its financial and psychological burden and because it is of no proven benefit.

METHODS

The present study targeted an Italian 2-yearly screening programme (Emilia-Romagna Region, 1997-2002). An electronic dataset of 647,876 eligible negative mammography records from 376,257 women aged 50-69 years was record-linked with the regional breast cancer registry. The statistical analysis addressed the following research questions: (1) the prevalence of recommendation for early (<24 months) rescreen (RES) among negative mammography reports; (2) factors associated with the likelihood of a women receiving RES; and (3) whether women receiving RES and women receiving standard negative reports differed in terms of proportional incidence of interval breast cancer, recall rate at the next rescreen, detection rate of breast cancer at the next rescreen and the odds of having late-stage breast cancer during the interscreening interval and at the next rescreen.

RESULTS

RES was used in eight out of 13 screening centres, where it was found in 4171 out of 313,320 negative reports (average rate 1.33%; range 0.05%-4.33%). Reports with RES were more likely for women aged 50-59 years versus older women (odds ratio (OR) 1.33; 95% CI 1.25-1.42), for the first versus subsequent screening rounds (OR 1.91; 95% CI 1.79-2.04) and with a centre-specific recall rate below the average of 6.2% (OR 1.41; 95% CI 1.32-1.50). RES predicted a 3.51-fold (95% CI 0.94-9.29) greater proportional incidence of first-year interval cancers, a 1.90-fold (95% CI 1.62-2.22) greater recall rate at the next screen, a 1.72-fold (95% CI 1.01-2.74) greater detection rate of cancer at the next screen and a non-significantly decreased risk of late disease stage (OR 0.59; 95% CI 0.23-1.53).

CONCLUSION

The prevalence of RES was in line with the maximum standard level established by the Italian national guidelines. RES identified a subset of women with greater incidence of interval cancers and greater prevalence of cancers detected at the next screen.