Mitotic activity index in interval breast cancers

Digital breast tomosynthesis in mammographic screening: false negative cancer cases in the To-Be 1 trial

OBJECTIVES

The randomized controlled trial comparing digital breast tomosynthesis and synthetic 2D mammograms (DBT + SM) versus digital mammography (DM) (the To-Be 1 trial), 2016-2017, did not result in higher cancer detection for DBT + SM. We aimed to determine if negative cases prior to interval and consecutive screen-detected cancers from DBT + SM were due to interpretive error.

METHODS

Five external breast radiologists performed the individual blinded review of 239 screening examinations (90 true negative, 39 false positive, 19 prior to interval cancer, and 91 prior to consecutive screen-detected cancer) and the informed consensus review of examinations prior to interval and screen-detected cancers (n = 110). The reviewers marked suspicious findings with a score of 1-5 (probability of malignancy). A case was false negative if ≥ 2 radiologists assigned the cancer site with a score of ≥ 2 in the blinded review and if the case was assigned as false negative by a consensus in the informed review.

RESULTS

In the informed review, 5.3% of examinations prior to interval cancer and 18.7% prior to consecutive round screen-detected cancer were considered false negative. In the blinded review, 10.6% of examinations prior to interval cancer and 42.9% prior to consecutive round screen-detected cancer were scored ≥ 2. A score of ≥ 2 was assigned to 47.8% of negative and 89.7% of false positive examinations.

CONCLUSIONS

The false negative rates were consistent with those of prior DM reviews, indicating that the lack of higher cancer detection for DBT + SM versus DM in the To-Be 1 trial is complex and not due to interpretive error alone.

CRITICAL RELEVANCE STATEMENT

The randomized controlled trial on digital breast tomosynthesis and synthetic 2D mammograms (DBT) and digital mammography (DM), 2016-2017, showed no difference in cancer detection for the two techniques. The rates of false negative screening examinations prior to interval and consecutive screen-detected cancer for DBT were consistent with the rates in prior DM reviews, indicating that the non-superior DBT performance in the trial might not be due to interpretive error alone.

KEY POINTS

• Screening with digital breast tomosynthesis (DBT) did not result in a higher breast cancer detection rate compared to screening with digital mammography (DM) in the To-Be 1 trial. • The false negative rates for examinations prior to interval and consecutive screen-detected cancer for DBT were determined in the trial to test if the lack of differences was due to interpretive error. • The false negative rates were consistent with those of prior DM reviews, indicating that the lack of higher cancer detection for DBT versus DM was complex and not due to interpretive error alone.

Quality of life among women with symptomatic, screen-detected, and interval breast cancer, and for women without breast cancer: a retrospective cross-sectional study from Norway

Purpose

Breast cancers detected at screening need less aggressive treatment compared to breast cancers detected due to symptoms. The evidence on the quality of life associated with screen-detected versus symptomatic breast cancer is sparse. This study aimed to compare quality of life among Norwegian women with symptomatic, screen-detected and interval breast cancer, and women without breast cancer and investigate quality adjusted life years (QALYs) for women with breast cancer from the third to 14th year since diagnosis.

Methods

This retrospective cross-sectional study was focused on women aged 50 and older. A self-reported questionnaire including EQ-5D-5L was sent to 11,500 women. Multivariable median regression was used to analyze the association between quality of life score (visual analogue scale 0–100) and detection mode. Health utility values representing women’s health status were extracted from EQ-5D-5L. QALYs were estimated by summing up the health utility values for women stratified by detection mode for each year between the third and the 14th year since breast cancer diagnosis, assuming that all women would survive.

Results

Adjusted regression analyses showed that women with screen-detected (n = 1206), interval cancer (n = 1005) and those without breast cancer (n = 1255) reported a higher median quality of life score using women with symptomatic cancer (n = 1021) as reference; 3.7 (95%CI 2.2–5.2), 2.3 (95%CI 0.7–3.8) and 4.8 (95%CI 3.3–6.4), respectively. Women with symptomatic, screen-detected and interval cancer would experience 9.5, 9.6 and 9.5 QALYs, respectively, between the third and the 14th year since diagnosis.

Conclusion

Women with screen-detected or interval breast cancer reported better quality of life compared to women with symptomatic cancer. The findings add benefits of organized mammographic screening.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11136-021-03017-7.

Interval Cancers in Breast Cancer Screening: Comparison of Stage and Biological Characteristics with Screen-Detected Cancers or Incident Cancers in the Absence of Screening

Aims and background

To analyze stage distribution and biological features of interval cancers observed in Verona mammography screening compared to screen-detected cancers and “clinical” cancers occurring in the absence of screening, as provided by the Veneto Cancer Registry.

Methods and study design

Screen-detected cancers were identified in the screening archives. Interval cancers and clinical cancers (occurring in women never screened or not yet invited) were identified through the local cancer registry. Studied variables were age, stage, pathological pT and pN category, histological grading, estrogen and progesterone receptor status, and proliferation index (Ki67).

Results

We compared 95 interval cancers, 761 screen-detected cancers, and 1873 clinical cancer cases. Interval cancers had more aggressive features than screen-detected cancers, the difference being statistically significant for pT (P = 10–6), pN (P = 0.0003), grading (P = 0.007), estrogen receptors (P = 0.0006), and progesterone receptors (P = 0.00005), but not for Ki67 (P = 0.18). The features of interval cancers were not more aggressive than those of clinical cancers for pT (P = 0.84), pN (P = 0.33), grading (P = 0.61), estrogen receptors (P = 0.48), and progesterone receptors (P = 0.69), and were better for Ki67 (P = 0.02). In contrast, screen-detected cancers showed significantly better features than clinical cancers, for all studied variables: pT (P = 10–6), pN (P = 10–6), grading (P = 10–6), estrogen receptors (P = 10–5), progesterone receptors (P = 10–6), and Ki67 (P = 10–6).

Conclusions

Our findings are consistent with the length biased sampling hypothesis of interval cancers having a faster growth rate and a less favorable presentation than screen-detected cancers. Compared to clinical cancers, interval cancers had similar features, whereas screen-detected cancers had definitely more favorable features. This finding suggests, rather than a faster growth rate for interval cancers, a slower growth rate for screen-detected cancers, which, together with diagnostic anticipation, may explain a certain degree of overdiagnosis.

Differential expression of prognostic biomarkers between interval and screen-detected breast cancers: does age or family history matter?

The aim of this study was to compare tumor expression of prognostic biomarkers between interval breast cancers and screen-detected breast cancers overall, and according to age at diagnosis and familial risk. Tissue micro-arrays were constructed from 98 breast cancers (47 interval and 51 screen-detected) diagnosed in women in the Cancer Genetics Network. Arrays were immuno-stained to compare protein expression of six biomarkers including estrogen and progesterone receptor (ER/PR), Her2/neu, EGFR, cytokeratin 5/6, and Ki67. Fisher's Exact test was used to compare expression between interval and screen-detected cancers. Interval cancers were larger (P = 0.04), higher stage (P < 0.001), and more likely to have lobular histology (P = 0.01) than screen-detected cancers. Overall, interval cancers more often overexpressed EGFR (P = 0.01) and were somewhat more likely to be ER- (55% vs. 43%, P = 0.3), and triple negative (ER-/PR-/Her2-) (21 vs. 12%, P = 0.26). A greater difference in the proportion of interval versus screen-detected tumors that were ER- (53 vs. 35%; P = 0.29), PR- (35 vs. 21%; P = 0.25) and EGFR+ (17 vs. 0%; P = 0.02) was evident among women over 50. There was a trend toward differential expression among women with familial risk for PR- (P = 0.005) and triple negative status (P = 0.02). This study provides new data indicating that EGFR may be important in the etiology of interval cancer and be a possible therapeutic target. Our data also suggest that biological differences between interval and screen-detected cancers are more defined in older women. Future studies to confirm this finding and to elucidate novel markers for characterizing interval cancers may be more beneficial to this subgroup.

Phosphohistone H3 expression has much stronger prognostic value than classical prognosticators in invasive lymph node-negative breast cancer patients less than 55 years of age

The proliferation factor mitotic activity index is the strongest prognostic factor in early breast cancer, but it may lack reproducibility. We analyzed the prognostic value of phosphohistone H3, a marker of cells in late G(2) and M phase, measuring highly standardized immunohistochemical nuclear phosphohistone H3 expression by subjective counts and digital image analysis. Expression was compared with classical clinico-pathologic prognostic variables and the mitotic activity index in 119 node-negative invasive breast cancers in patients less than 55 years old treated with adjuvant systemic chemotherapy with long-term follow-up (median 168 months). Nineteen patients (16%) developed distant metastases and 16 (13%) died. Strong phosphohistone H3 expression occurred preferentially in the peripheral growing front; counts were highly reproducible between observers (R=0.92) and highly consistent with digital image analysis (R=0.96). Phosphohistone H3 correlated (P<0.05) with tumor diameter, estrogen receptor, carcinoma grade, and mitotic activity index. Phosphohistone H3 values were systematically (80%) higher than the mitotic activity index. Receiver-operating curve analysis objectively showed that phosphohistone H3 <13 (n=53; 45% of all cases) vs phosphohistone H3> or =13 (n=66; 55% of all cases) was the strongest prognostic threshold, with 20-year recurrence-free survival of distant metastases of 96 and 58%, respectively (P=0.0002, HR=9.6). Mitotic activity index was the second strongest prognostic variable (P=0.003, HR=3.9). In multivariate analysis, phosphohistone H3 <13 vs> or =13 exceeded the prognostic value of the mitotic activity index. None of the other classical prognostic factors examined offered prognostic value additional to phosphohistone H3. Phosphohistone H3 is by far the strongest prognostic variable in early invasive node-negative breast cancer patients less than 55 years old with long-term follow-up.

Preoperative selection of symptomatic breast cancer patients appropriate for lymphatic mapping and sentinel node biopsy

BACKGROUND

This study examines whether preoperative ultrasound-assessed tumour diameter and diagnostic core biopsy-determined grade can be used to select those most likely to benefit from SLNB (i.e. those that are "node negative") before their definitive operation.

METHODS

Breast ultrasound (US) and a simultaneous core biopsy was performed in all patients at their initial presentation, and their estimates of tumor size and grade compared with the final pathological specimen (FPS).

RESULTS

Of the T1 group 47% had lymphatic metastases as did 49% of those with grade I or II cancers. By combining these measures, however, subgroups of patients with lower rates of nodal metastases were identified (32% of patients with T1, non-grade III disease had lymphatic disease while only 15% of those with T < 1.5 cm, non-grade III cancers had such metastases).

CONCLUSION

Combination of the US and ultrasound guided core biopsy (UGCB) may however identify subgroups unlikely to have axillary disease that are therefore suitable for SLNB.

The prognostic value of proliferation in lymph-node-negative breast cancer patients is age dependent

In lymph-node-negative invasive breast cancer patients<55 years, the proliferation marker mitotic activity index (MAI) has previously been shown to be the strongest prognosticator. In studies without age definition, MAI was not strongly prognostic. We investigated the age dependency of the prognostic value of proliferation for distant metastasis-free (MFS) and overall cancer-related survival (OS) in 1004 histologically diagnosed T1-3N0M0 invasive breast cancers (n=516, <55 years; n=322, 55-70 years; n=166, >70 years) without systemic adjuvant therapy and long follow-up (median: 108 months). The MAI decreases with age and the prognostic value of MAI varied by age group. For patients<55 years, hazard ratios (HR) for MAI>or=10 versus<10 for MFS and OS were 3.1 and 4.4, respectively (P<.0001 for both), but only 1.9 and 1.9 (P=.004 and .006) for patients aged 55-70 years, while over 70 years, MAI was not significant (P=.11). The prognostic value of proliferation was age-dependent. Prognostic breast cancer studies must clearly indicate the age group being studied.

Lymph node status as a guide to selection of available prognostic markers in breast cancer: the clinical practice of the future?

Prognosticators evaluating survival in breast cancer vary in significance in respect to lymph node status. Studies have shown e.g. that HER2/neu immunohistochemistry or HER2/neu gene amplification analysis do perform well as prognosticators in lymph node positive (LN +) patients but are less valuable in lymph node negative (LN -) patients. We collected data from different studies and tried to evaluate the relative significance of different prognosticators in LN+/LN- patient groups. In LN+ patients HER2/neu and E-cadherin immunohistochemistry were the statistically most significant prognosticators followed by proliferation associated features (mitotic counts by SMI (standardised mitotic index) or MAI (mitotic activity index), or S-phase fraction). Bcl-2 immunohistochemistry was also significant but p53 and cystatin A had no significance as prognosticators. In LN- patients proliferation associated prognosticators (SMI, MAI, Ki-67 index, PCNA immunohistochemistry, S-phase fraction) are especially valuable and also Cathepsin D, cystatin A, and p53 are significant, but HER2/neu or bcl-2, or E-cadherin less significant or without significance. We find that in studies evaluating single prognosticators one should distinguish between prognosticators suitable for LN+ and LN- patients. This will allow the choice of best prognosticators in evaluating the prospects of the patient. The distinction between LN+ and LN- patients in this respect may also be of special value in therapeutic decisions.

Role of mammography screening as a predictor of survival in postmenopausal breast cancer patients

We examined the effect of population-based screening programme on tumour characteristics by comparing carcinomas diagnosed during the prescreening (N=341) and screening (N=552) periods. We identified screen detected (N=224), interval (N=99) and clinical cancer (N=229) cases. Median tumour size and proportion of axillary lymph node negative cases were 1.5 cm and 65% in the screen detected group, 2.0 cm and 44% in cases found outside the screening, and 3.2 cm and 41% in the cases from the prescreening period. Survival of the breast cancer patients was 66% (95% CI, 60-71%) in the prescreening era group and 73% (95% CI, 66-78%) in the screening era group after 10 years of follow-up. In the screening era group the survival of the screen detected cases was 86% (95% CI, 80-90%) and that of the clinical cancer cases 73% (95% CI, 66-78%) after 10 years. In multivariate analysis the risk of breast cancer death was not significantly different between the prescreening and screening periods (HR 0.82; 95% CI 0.59-1.12, P=0.21). Detection by screening was not an independent prognostic factor in multivariate analysis (HR 0.75; CI 95% 0.50-1.12; P=0.17).

Multivariate prognostic evaluation of the mitotic activity index and fibrotic focus in node-negative invasive breast cancers

We validated with univariate and multivariate (Cox) analysis, the prognostic value of the mitotic activity index (MAI), the fibrotic focus (FF) and other prognosticators in 448 patients with lymph node-negative (LN-) invasive breast cancer <55 years without adjuvant systemic treatment (72.5 months median follow-up, range 4-119). Of these patients, 24.8% developed distant and 1.6% loco-regional recurrence. FF showed excellent inter-observer reproducibility (kappa = 0.93). Strong prognosticators were MAI, grade, nuclear atypia, FF and the St. Gallen criterion (SG). The subgroup with excellent survival selected by SG was only 16% of all patients, implying over-treatment of more than 70% of all LN- patients when using SG as adjuvant therapy selection criterion. If MAI <10, 13% showed distant metastases, contrasting with 41% if MAI > or = 10. FF was prognostic in the ductal and mixed ductal cancers, but not in the lobular and other subtype cancers. Patients with invasive (mixed) ductal cancers with FF absent, FF < 1/3 or FF > 1/3 of the tumour area, had distant metastasis rates of 17%, 35% and 48%; in MAI < 10 and FF absent, FF < 1/3 or FF > 1/3, metastasis rates were 11%, 13% and 42% and if MAI > or = 10, metastasis rates were 31%, 48% and 50%, respectively. In the 12 patients with MAI < 10 and a large FF > 1/3, event-free survival was similar to patients with MAI > or = 10. With multiple regression MAI < 10 versus > or = 10 is the strongest prognosticator (also stronger than the SG). The FF may be important as it has additional prognostic value to the MAI in the small subgroup of invasive ductal or mixed-ductal breast cancer patients with combined MAI < 10 and an FF > 1/3 of the tumour area.

Prospective Multicenter Validation of the Independent Prognostic Value of the Mitotic Activity Index in Lymph Node–Negative Breast Cancer Patients Younger Than 55 Years

Purpose

To validate the independent strong prognostic value of mitotic activity index (MAI) in lymph node (LN) –negative invasive breast cancer patients younger than 55 years in a nationwide multicenter prospective study.

Patients and Methods

Analysis of routinely assessed MAI and other prognosticators in 516 patients (median follow-up, 118 months; range, 8 to 185 months), without systemic adjuvant therapy or previous malignancies.

Results

Distant metastases occurred in 127 patients (24.6%); 90 (17.4%) died as a result of metastases. MAI (< 10, ≥ 10) showed strong association with recurrence (hazard ratio [HR], 3.12; 95% CI, 2.17 to 4.50; P ≤ .0001) and mortality (HR, 4.42; 95% CI, 2.79 to 7.01; P < .0001). The absolute difference in 10-year Kaplan-Meier estimates of time to distant recurrence as well as survival was 22% between MAI less than 10 versus ≥ 10. This effect was independent of age, estrogen receptor (ER) status, and tumor diameter (which were significant prognosticators). In multivariate analysis with regard to patient age, tumor diameter, grade, ER status, and the St Gallen criterion, MAI proved to be an independent and the strongest prognosticator. Tubular formation (TF) and nuclear atypia (NA), as constituents of (expert revised) grade, had no (for TF) or limited (for NA, P = .048) additional prognostic value to the MAI. In the group with MAI less than 10, MAI less than 3 versus more than 3 had additional value but the classical threshold of 0 to 5 v 6 to 10 did not. With this additional subdivision of MAI as less than 3, 3 to 9, and more than 9, NA lost its additive prognostic value.

Conclusion

The MAI is the strongest, most widely available, easily assessable, inexpensive, well-reproducible prognosticator and is well suited to routinely differentiate between high- and low-risk LN-negative breast cancer patients younger than 55 years.

Cell proliferation and cell cycle control: a mini review

Tumourigenesis is the result of cell cycle disorganisation, leading to an uncontrolled cellular proliferation. Specific cellular processes-mechanisms that control cell cycle progression and checkpoint traversation through the intermitotic phases are deregulated. Normally, these events are highly conserved due to the existence of conservatory mechanisms and molecules such as cell cycle genes and their products: cyclins, cyclin dependent kinases (Cdks), Cdk inhibitors (CKI) and extra cellular factors (i.e. growth factors). Revolutionary techniques using laser cytometry and commercial software are available to quantify and evaluate cell cycle processes and cellular growth. S-phase fraction measurements, including ploidy values, using histograms and estimation of indices such as the mitotic index and tumour-doubling time indices, provide adequate information to the clinician to evaluate tumour aggressiveness, prognosis and the strategies for radiotherapy and chemotherapy in experimental researches.

Breast carcinoma diagnosis, treatment, and prognosis before and after the introduction of mass mammographic screening

BACKGROUND

The introduction of breast carcinoma screening leads to early detection and is believed to reduce mortality and increase the proportion of patients for whom breast-conserving surgery is possible.

METHODS

In 1992, a population-based mammographic screening program was introduced in the Dutch city of Tilburg and its surroundings; the program achieved total coverage in 1996. The authors examined the effects of this screening program by investigating disease stage, treatment, and survival among women diagnosed with breast carcinoma at a teaching hospital in Tilburg during the periods 1985-1991 and 1992-1999.

RESULTS

Between January 1, 1985, and December 31, 1999, 1400 patients were diagnosed with breast carcinoma. Among patients ages 50-69 years, the proportion of TNM Stage I breast carcinoma increased from 24% in 1985-1991 to 45% in 1992-1999 (P<0.001). The proportion of patients age <50 years with invasive breast carcinoma who underwent breast-conserving surgery decreased from 45% to 33% (P=0.011). Among patients ages 50-69 years, the overall survival rate during the period from 1992 to 1999 was significantly greater than the corresponding rate during the period from 1985 to 1991 (P=0.0009). Even after adjustments were made for tumor stage and patient age, a slight reduction in mortality risk was observed in this age group. No difference in stage distribution or prognosis was found among patients age <50 years or among patients age > or =70 years. Of the 168 invasive malignancies found in patients ages 50-69 years between 1997 and 1999, 68 (40%) were detected by the screening program, 47 (28%) were interval malignancies, and 53 (32%) were detected in nonparticipants or in women who did not participate in 1 or more screening rounds. Patients with screen-detected tumors had a much more favorable prognosis than did patients with interval malignancies (P=0.0018) or patients with clinically detected breast carcinoma (P<0.0001).

CONCLUSIONS

Between 1992 and 1999, after the introduction of breast carcinoma screening, improved prognosis and more favorable tumor stage were observed among patients ages 50-69 years. Even after the screening program was fully implemented in 1996, the majority of invasive malignancies still were detected between screening rounds or in patients who did not participate in the program.