Prognosis after Local Recurrence in Patients with Early-Stage Breast Cancer Treated without Chemotherapy

Background: Many women with early-stage breast cancer are predicted to be at sufficiently low risk for recurrence that they may forego chemotherapy. Nevertheless, some low-risk women will experience a local recurrence, and for them the risk of death increases significantly thereafter. The utility of initiating chemotherapy at the time of local recurrence has not been adequately addressed. The purpose of this study is to identify, in a hospital-based series of patients with early-stage breast cancer who were not treated with chemotherapy, those factors which predict death post local recurrence. Methods: We identified 135 women who were diagnosed with early-stage breast cancer (node-negative, <5 cm) and who did not receive chemotherapy at diagnosis and who developed a local recurrence. They were diagnosed between 1987 and 2000 and treated at Women’s College Hospital. For each patient, we abstracted information on the initial cancer (age at diagnosis, tumour size, tumour grade, ER status, PR status, HER2 status, lympho-vascular invasion, type of surgery, use of radiotherapy, tamoxifen and chemotherapy), the time from initial diagnosis to local recurrence and treatment at recurrence. The Kaplan–Meier method was used to estimate the ten-year actuarial risk of breast cancer death post recurrence. A Cox proportional hazards model was used to estimate multivariate hazard ratios for the various factors. Results: Among the 135 women in the cohort, the mean time from initial diagnosis to local recurrence was 7.8 years (range: 0.3 to 22.6 years). A total of 38 of the 135 women (28.1%) died of breast cancer a mean of 5.3 years after experiencing the local recurrence (range: 0.3 to 17 years). The ten-year breast cancer survival post local recurrence was 71% and the 15-year survival was 65%. In a multivariate analysis, it was found that factors that were significantly associated with death after local recurrence were (1) PR-negative status, (2) young age at diagnosis (<40 years) and (3) time to local recurrence less than 2 years. Nine percent of women received chemotherapy at the time of local recurrence. Conclusions: For breast cancer patients with a low baseline risk of mortality, the risk of death after an isolated local recurrence is substantial. Systemic treatment at the time of local recurrence needs further study.

Countercurrents: DCIS or Cancer? Why All the Confusion?

At present, women with ductal carcinoma in situ are counseled that they have a pre-malignant condition which carries the possibility of progression to a fully malignant breast cancer. However, in most cases, the treatment of DCIS resembles that of a small invasive breast cancer and this is a source of confusion to many. In order to properly evaluate the benefit of radiotherapy, mastectomy and contralateral mastectomy, it is necessary to consider the risks of ipsilateral invasive cancer and of contralateral breast cancer in women with DCIS and with small invasive breast cancer. Several registry-based studies indicate that the risks of ipsilateral and contralateral cancer are similar in the two conditions and therefore a similar approach to treatment is rational.

A Validation of Methods for the Evaluation of Observational Studies of Screening Mammography: An Exploratory Analysis Based on Simulating Screening Cohorts

Background

The degree of confidence one should place on non-randomised observational trials studies which estimate the benefit of screening depends on the validity of the analytic method employed. As is the case for all observational trials, screening evaluation studies are subject to bias. The objective of this study was to create a simulated data set and to compare four analytic methods in order to identify the method which was the least biased in terms of estimating the underlying hazard ratio.

Methods

We simulated a cohort of 100,000 women who were accorded US national rates of breast cancer incidence and breast cancer mortality over their lifetime. We assigned at random one-half of them to initiate mammography screening between ages 50 and 60. We used four different analytic approaches to estimate the hazard ratio under a null model (true HR = 1.0) and under a protective model (true HR = 0.80). Two models used the entire data set (with and without including mammography as a time-dependent covariate) and two models invoked matching of screened women with unscreened women (with and without excluding of women who had a mammogram after study initiation). For each of the four analytic methods, we compared the observed hazard ratio with the true hazard ratio. We considered an analytic method to be valid if the observed hazard ratio was close to the true hazard ratio.

Results

Two simple analytic methods generated biased results that led to spurious protective effects observed when none was there. The least biased method was based on matching screened and unscreened women and which emulated a randomized trial design, wherein the unexposed control had no mammogram prior to study entry, but she was not excluded or censored if she had a mammogram after the index date.

Conclusion

There is no single ideal method to analyze observational data to evaluate the effectiveness of screening mammography (ie, which generates an unbiased estimates of the underlying hazard ratio) but designs which emulate randomised trials should be promoted.

Association of a Diagnosis of Ductal Carcinoma In Situ With Death From Breast Cancer

IMPORTANCE

It is not clear to what extent a diagnosis of ductal carcinoma in situ (DCIS) impacts a woman's lifetime risk of dying of breast cancer. Under ideal circumstances, treatment will eliminate the risk of invasive ipsilateral recurrence and prevent subsequent mortality from breast cancer. The risk of dying of breast cancer after a diagnosis of DCIS had not been compared with that of women without cancer in the general population.

OBJECTIVE

To determine the risk of death from breast cancer in a large cohort of patients treated for DCIS and to compare the risk with that of women in the general population.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included data for women who had first primary DCIS diagnosed between 1995 and 2014 from the Surveillance, Epidemiology and End Results (SEER) registries database. Women with DCIS underwent surgical treatment, and approximately half also received radiotherapy. These women were followed from the date of DCIS diagnosis until death from breast cancer or date of last follow-up. Women in the general population without breast cancer were analyzed as controls. Follow-up information was available up to December 2016. The data were analyzed in March 2020.

EXPOSURES

Patients with DCIS who underwent surgical treatment.

MAIN OUTCOMES AND MEASURES

Breast cancer death was the main outcome. Standardized mortality ratios were estimated by comparing deaths from breast cancer among women diagnosed with DCIS with expected deaths from breast cancer among women in the general population who did not have cancer. Expected probability of death from breast cancer in the general population was calculated by an incidence-based mortality approach using standardized SEER-based incidence and case-fatality rates. Probability of breast cancer death was estimated based on the assumption that a cancer-free control was cancer free on the date the woman with DCIS was diagnosed and was studied until the end of follow-up.

RESULTS

A total of 144 524 women diagnosed with first primary DCIS were included (mean [SD] age at diagnosis, 57.4 [11.0] years). There were 1540 deaths from breast cancer in the cohort. Based on SEER-based incidence and case-fatality rates, 458 breast cancer deaths were expected in an equivalent number of cancer-free women from the general population with equal follow-up. The standardized mortality ratio for death from breast cancer among women with DCIS was 3.36 (95% CI, 3.20-3.53). The elevated risk of death persisted more than 15 years after diagnosis.

CONCLUSIONS AND RELEVANCE

In the population studied, the risk of dying of breast cancer was increased 3-fold after a diagnosis of DCIS. This suggests that our current treatment focus on preventing invasive recurrence is insufficient to eliminate all deaths from breast cancer after DCIS.

Retesting of women who are negative for a BRCA1 and BRCA2 mutation using a 20-gene panel

BACKGROUND

The value of retesting women who previously tested negative for a pathogenic variant (mutation) in BRCA1 and BRCA2 using an expanded panel of breast and ovarian cancer genes is unclear.

METHODS

We studied 110 BRCA1/2-negative women who were retested using a panel of 20 breast and/or ovarian cancer susceptibility genes at the Advanced Molecular Diagnostics Laboratory (AMDL) at Mount Sinai Hospital in Toronto between March 2017 and March 2019. All patients had previously tested negative for BRCA pathogenic variants at the AMDL between January 2012 and March 2018 and were subsequently referred for retesting by their physician.

RESULTS

Overall, six pathogenic variants in genes other than BRCA1 and BRCA2 were found (prevalence 5.5%). There were two pathogenic variants found in RAD51C, and one found in each of BRIP1, PALB2, PMS2 and PTEN. The prevalence of pathogenic variants was 6.5% for women affected with cancer (6 of 93), including 4.9% for women with breast cancer (4 of 82) and 22.2% for women with ovarian cancer (2 of 9). None of the 17 unaffected women had a clinically significant or pathogenic variant. There were 44 women (40%) for whom the result of the panel test was inconclusive due to the detection of a variant of uncertain significance.

CONCLUSIONS

Our findings indicate that the retesting of BRCA1/2-negative individuals with an expanded panel of 20 breast and ovarian cancer genes can produce clinically relevant results, with a yield of 5.5% for pathogenic variants in genes other than BRCA1 and BRCA2.

Time to death in breast cancer patients as an indicator of treatment response

PURPOSE

To describe the mortality experience of women who die of breast cancer in the 20-year period post-diagnosis using various metrics, including annual mortality rates, Kaplan-Meier survival curves and time-to-death histograms.

METHODS

We generated three visual representations of SEER-based and hospital-based breast cancer patient cohorts using three different metrics of mortality.

RESULTS

The greatest impact of most prognostic factors was on the probability of latent metastases present after treatment, but for some factors the primary impact was on the time to death for those women with metastases.

CONCLUSIONS

The use of time-to-death statistics to display mortality benefits for treated versus untreated women helps facilitate the distinction between treatments which increase the likelihood of cure and treatments that delay cancer growth.

Association of Radiotherapy With Survival in Women Treated for Ductal Carcinoma In Situ With Lumpectomy or Mastectomy

IMPORTANCE

Patients with ductal carcinoma in situ (DCIS) are treated with radiotherapy to reduce their risk of local invasive recurrence after breast-conserving surgery. However, the association of radiotherapy with breast cancer survival in patients with DCIS has not yet been clearly established.

OBJECTIVE

To determine the extent to which radiotherapy is associated with reduced risk of breast cancer mortality in a large cohort of patients treated for DCIS, using a propensity score-based matching approach.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study of women who had first primary DCIS diagnosed between 1998 and 2014 used data from the Surveillance, Epidemiology, and End Results 18 registries database. Information on age and year of diagnosis, ethnicity, income, tumor size, tumor grade, estrogen receptor status, all treatments (surgery and radiation), and outcomes (invasive local recurrence and death from breast cancer) was abstracted for 140 366 women diagnosed with first primary DCIS. Three separate comparisons were performed using 1:1 matching: lumpectomy with radiation vs lumpectomy alone; lumpectomy alone vs mastectomy; and lumpectomy with radiation vs mastectomy.

EXPOSURES

Use of radiotherapy and/or extent of surgery.

MAIN OUTCOMES AND MEASURES

Crude and adjusted 15-year breast cancer-specific mortality.

RESULTS

Of the 140 366 patients with DCIS in the cohort (109 712 [78.2%] white; mean [SD] age, 58.8 [12.3] years), 35 070 (25.0%) were treated with lumpectomy alone, 65 301 (46.5%) were treated with lumpectomy and radiotherapy, and 39 995 (28.5%) were treated with mastectomy. The actuarial 15-year breast cancer mortality rate was 2.33% for patients treated with lumpectomy alone, 1.74% for patients treated with lumpectomy and radiation, and 2.26% for patients treated with mastectomy. The adjusted hazard ratios for death were 0.77 (95% CI, 0.67-0.88) for lumpectomy and radiotherapy vs lumpectomy alone (29 465 propensity-matched pairs), 0.91 (95% CI, 0.78-1.05) for mastectomy alone vs lumpectomy alone (20 832 propensity-matched pairs), and 0.75 (95% CI, 0.65-0.87) for lumpectomy and radiotherapy vs mastectomy (29 865 propensity-matched pairs).

CONCLUSIONS AND RELEVANCE

In patients with DCIS, treatment with lumpectomy and radiotherapy was associated with a significant reduction in breast cancer mortality compared with either lumpectomy alone or mastectomy alone. This suggests that the survival benefit of radiation is likely not due to local control, but rather to systemic effects.

Is invasion a necessary step for metastases in breast cancer?

PURPOSE

To review the empirical evidence to support the conventional (sequential) model of breast cancer progression, which is based on the paradigm that cancer passes through several stages, including an in situ stage prior to an invasive stage, and thereafter (in some cases) disseminates to the lymph nodes and distant organs.

METHODS

We review the cancer literature of the last 50 years which relates to the prevention of invasive breast cancer (through radiotherapy or surgery) and reductions in the mortality for breast cancer.

RESULTS

For both invasive cancers and DCIS, the literature indicates that prevention of in-breast invasive recurrences does not prevent death from breast cancer. Moreover, the presence of residual cancer cells in the breast after breast-conserving surgery does not compromise the cure rate.

CONCLUSION

We propose an alternate (parallel) model of breast cancer wherein there is a small pool of cancer stem cells which have metastatic potential from their inception and which disseminate synchronously through several routes-to the breast stroma, to the lymph nodes and to distant organs. Cancer cells which disseminate to the breast give rise to cells which make up the bulk of the tumour mass but these are not the source of the distant metastases.

A comparison of two models for breast cancer mortality for women with ductal carcinoma in situ: an SEER-based analysis

BACKGROUND

Approximately 1% of patients with ductal carcinoma in situ (DCIS) will die of breast cancer within 10 years. Women who develop an invasive breast cancer after DCIS have a much greater risk of dying than those who do not and it is often stated that these deaths are a consequence of metastases from the invasive in-breast recurrence. This progression is the result of a two-step process: first local invasive recurrence and then spread beyond the breast. A large proportion of women who die of DCIS have no record of invasive recurrence. We used SEER data and a simulation approach to test whether the actual mortality data are consistent with the two-step model.

METHODS

First, we constructed Kaplan-Meier mortality curves for all patients with pure DCIS and with small node-negative invasive breast cancers in the Surveillance, Epidemiology and End Results (SEER) registries database (1998-2014). We then constructed, through simulation, theoretical breast cancer mortality curves. To model the two-step scenario, we applied the annual incidence rates of incident invasive cancer following DCIS and of death from invasive cancer after DCIS to a theoretical cohort of 100,000 women.

RESULTS

The observed 15-year breast cancer-specific mortality rate for patients with pure DCIS in the SEER database was 2.0%. The expected mortality for DCIS patients (assuming a two-step process) was only 1.1% at 15 years. Assuming the mortality rates following DCIS were one-half of those observed for patients with small invasive breast cancers, the expected mortality at 15 years post-DCIS was 2.1%.

CONCLUSIONS

In the SEER database, we observed far more deaths from DCIS than would be expected under a model where all deaths from breast cancer occur amongst women who experience an invasive local recurrence. This lends support to the hypothesis that DCIS mortality is not restricted to those women who experience an in-breast invasive cancer and that DCIS has properties similar to small invasive breast cancers.

Impact of microinvasion on breast cancer mortality in women with ductal carcinoma in situ

BACKGROUND

Ductal carcinoma in situ (DCIS) is a neoplastic proliferation of epithelial cells which is confined within the basement membrane of the mammary ductal-lobular system. It is of interest to determine to what extent the potential to metastasize increases for DCIS patients when the basement membrane is breached (i.e. microinvasion is present).

METHODS

We retrieved the records of 525,395 women who had either first primary DCIS or small (≤ 2.0 cm) node-negative invasive breast cancer in the Surveillance, Epidemiology and End Results (SEER) registries database (1990-2013). For each patient, we extracted information on year of diagnosis, age at diagnosis, tumour size, tumour grade, oestrogen receptor status, use of radiotherapy, type of surgery, cause of death and follow-up time. We classified patients into four groups, according to the size of the invasive component of the primary tumour. We estimated the actuarial rate of breast cancer-specific mortality at ten and 20 years for women in each size category.

RESULTS

We identified 161,394 women with pure DCIS, 13,489 women with microinvasive carcinoma (≤ 0.1 cm of invasion), 153,856 women with invasive cancer 0.2-1.0 cm in size and 196,656 women with invasive cancer 1.1-2.0 cm in size. The 20-year actuarial breast cancer-specific mortality rate was 3.8% for women with pure DCIS, was 6.9% for women with microinvasive carcinoma, was 6.8% for women with invasive cancer 0.2-1.0 cm in size and was 12.1% for women with invasive cancer 1.1-2.0 cm in size. The adjusted hazard ratio for death associated with microinvasive carcinoma (vs. pure DCIS) was 2.00 (95% CI 1.76-2.26; p < 0.0001).

CONCLUSIONS

In terms of prognosis, microinvasive cancer more closely resembles small invasive cancer 0.2-1.0 cm) than pure DCIS. For invasive cancers under 1.0 cm, size has little impact on mortality.

Frequency of germline PALB2 mutations among women with epithelial ovarian cancer

Recent studies suggest that mutations in the partner and localizer of BRCA2 (PALB2) gene may predispose to ovarian cancer. It is of importance to clarify the prevalence and penetrance of PALB2 mutations in an unselected population so that clinical recommendations for prevention can be implemented. We evaluated the prevalence of germline mutations in PALB2 among 1421 epithelial ovarian cancer patients and 4300 European controls from the National Heart, Lung, and Blood Institute's Exome Sequencing Project dataset. Clinical information was obtained from medical records and survival status was determined by linkage. PALB2 coding exons were sequenced using next generation sequencing technology. Of the 1421 patients, three (0.21 %) had a germline PALB2 mutation compared to two of the 4300 control subjects (0.05 %). The mean age at diagnosis was 59 years (range 55-62) and all three women died within 2 years of diagnosis. A PALB2 mutation was associated with a four-fold, albeit not significant, increased risk of ovarian cancer (OR = 4.55; 95 % CI 0.76-27.24; P = 0.10). These results suggest that germline PALB2 mutations are rare. The true effect of such mutations on ovarian cancer risk require further study before the clinical relevance of inherited PALB2 mutations is established.

Wherein the authors attempt to minimize the confusion generated by their study "Breast cancer mortality after a diagnosis of ductal carcinoma in situ" by several commentators who disagree with them and a few who don't: a qualitative study

Various parties might wish to measure the impact of a given paper for the purpose of assigning merit to an author or institution [...]

Low-grade serous ovarian cancer: A review

Epithelial ovarian cancers can be divided into the more common, aggressive type II cancers and the less common, slow-growing type I cancers. Under this model, serous ovarian carcinomas can be subdivided into high-grade (type II) and low-grade (type I) tumours. The two-tier system for grading serous ovarian carcinomas is superior to more detailed grading systems in terms of predicting survival. Low-grade serous carcinomas typically present in young women and have a relatively good prognosis, despite being resistant to chemotherapy. Low-grade serous cancers have a high prevalence of KRAS and BRAF mutations, but a low prevalence of TP53 mutations (which are characteristic of high-grade serous cancers). Among women with low-grade serous ovarian cancer, the presence of a KRAS/BRAF mutation is a favorable prognostic factor. Studies of the mitogen-activated protein kinase (MAPK) inhibitor in low-grade serous ovarian cancer suggest that identifying MAPK mutations might eventually be useful in guiding treatment.

Genetic risk assessment and prevention: the role of genetic testing panels in breast cancer

Multigene panel tests are being increasingly used for the genetic assessment of women with an apparent predisposition to breast cancer. Here, we review all studies reporting results from individuals who have undergone multigene panel testing for hereditary breast cancer. Across all gene panel studies, the prevalence of pathogenic mutations was highest in BRCA1 (5.3%) and BRCA2 (3.6%) and was lowest in PTEN (0.1%), CDH1 (0.1%) and STK11 (0.01%). After BRCA1/2, the prevalence of pathogenic mutations was highest in CHEK2 (1.3%), PALB2 (0.9%) and ATM (0.8%). The prevalence of variants of unknown significance was highest in ATM (9.6%). Based on the prevalence and penetrance of pathogenic mutations and the prevalence of variants of unknown significance, it is our interpretation that BRCA1, BRCA2, PALB2 and CHEK2 are the best candidates for inclusion in a clinical multigene breast cancer panel.

Why have ovarian cancer mortality rates declined? Part III. Prospects for the future

Over the last 40 years, the age-adjusted ovarian cancer mortality rate in the USA declined by 23%. The decline in mortality paralleled a decline in incidence, which was largely due to changes in reproductive risk factors. There was no reduction in ovarian cancer case-fatality at 12 years, indicating that improvements in early detection or in treatment did not contribute to the decline in mortality. Here, we discuss potential strategies to further reduce ovarian cancer mortality through prevention, early detection and treatment. The first approach is to increase genetic testing, in order to identify women who are at a high risk of developing ovarian cancer and offer them preventive bilateral salpingo-oophorectomy. At present, up to 17% of ovarian cancers are potentially preventable through population-based genetic testing of known ovarian cancer susceptibility genes. The second approach is to increase the proportion of ovarian cancer patients who achieve a status of no residual disease through primary debulking surgery and subsequently receive adjuvant intraperitoneal chemotherapy. We believe that through a combination of screening to better identify low-volume advanced stage ovarian cancer, aggressive surgery to leave no residual disease and adjuvant intraperitoneal chemotherapy, the cure rate of ovarian cancer might be improved significantly.

Clinical outcomes in women with breast cancer and a PALB2 mutation: a prospective cohort analysis

BACKGROUND

Mutations in PALB2 predispose to breast cancer, but the effect on prognosis of carrying a PALB2 mutation has not been ascertained. We aimed to estimate the odds ratio for breast cancer in women with an inherited mutation in PALB2 and 10-year survival after breast cancer in patients who carry a PALB2 mutation.

METHODS

Between 1996 and 2012, patients with invasive breast cancer were recruited prospectively from 18 hospitals in Poland and genotyped for two deleterious mutations in PALB2 (509_510delGA and 172_175delTTGT). A control group of 4702 women without cancer was recruited for comparison. The primary endpoint was death from any cause, as determined by medical records from the Polish Ministry of the Interior and Administration. In patients with breast cancer, 10-year survival of carriers of a PALB2 mutation was calculated and compared with that of non-carriers.

FINDINGS

17 900 women with breast cancer were invited to participate, of whom 12 529 were genotyped successfully. A PALB2 mutation was present in 116 (0·93%, 95% CI 0·76-1·09) of 12 529 patients and in ten (0·21%, 0·08-0·34) of 4702 controls (odds ratio 4·39, 95% CI 2·30-8·37; p<0·0001). 10-year survival for women with breast cancer and a PALB2 mutation was 48·0% (95% CI 36·5-63·2), compared with 74·7% (73·5-75·8) for patients with breast cancer without a mutation (adjusted hazard ratio for death 2·27, 95% CI 1·64-3·15; p<0·0001).

INTERPRETATION

Women with a PALB2 mutation face an increased risk of breast cancer and might be at a higher risk of death from breast cancer compared with non-carriers. Increased surveillance should be offered to unaffected women who carry a PALB2 mutation.

FUNDING

Polish National Science Centre.

Overdiagnosis in breast cancer chemoprevention trials

Several randomized controlled trials have demonstrated that the preventive use of an antiestrogen agent such as tamoxifen, raloxifene, anastrozole, or exemestane will reduce the incidence of estrogen receptor (er)–positive breast cancers by 50% or more. The reduction in risk becomes apparent shortly after tamoxifen initiation. However, no mortality benefit has yet been demonstrated with tamoxifen or any other agent, an effect that might be statistical: that is, the statistical power to detect a difference in mortality could be lacking because deaths from breast cancer are far fewer in number than cases of breast cancer, and because the average time to cancer is much shorter than the time to death. In other words, it could be too early to see an effect. However, the lack of an observed survival benefit might also be a result of chemoprevention agents preferentially preventing cancers that would rarely lead to death. That paradigm extends the (controversial) concepts of overdiagnosis and of the potential for spontaneous regression of some lowgrade breast cancers [...]