Breast cancer--biology and malpractice

Machine learning-based prediction of breast cancer growth rate in vivo

Background

Determining the rate of breast cancer (BC) growth in vivo, which can predict prognosis, has remained elusive despite its relevance for treatment, screening recommendations and medicolegal practice. We developed a model that predicts the rate of in vivo tumour growth using a unique study cohort of BC patients who had two serial mammograms wherein the tumour, visible in the diagnostic mammogram, was missed in the first screen.

Methods

A serial mammography-derived in vivo growth rate (SM-INVIGOR) index was developed using tumour volumes from two serial mammograms and time interval between measurements. We then developed a machine learning-based surrogate model called Surr-INVIGOR using routinely assessed biomarkers to predict in vivo rate of tumour growth and extend the utility of this approach to a larger patient population. Surr-INVIGOR was validated using an independent cohort.

Results

SM-INVIGOR stratified discovery cohort patients into fast-growing versus slow-growing tumour subgroups, wherein patients with fast-growing tumours experienced poorer BC-specific survival. Our clinically relevant Surr-INVIGOR stratified tumours in the discovery cohort and was concordant with SM-INVIGOR. In the validation cohort, Surr-INVIGOR uncovered significant survival differences between patients with fast-growing and slow-growing tumours.

Conclusion

Our Surr-INVIGOR model predicts in vivo BC growth rate during the pre-diagnostic stage and offers several useful applications.

Reduced mortality for women with mammography-detected breast cancer in east Denmark and south Sweden

The 5-year relative survival from breast cancer in Denmark is 10 percentage points lower than in Sweden. This difference has been demonstrated previously as being caused partly by more involved lymph nodes and larger tumours in Denmark. Sweden has had nationwide mammography-screening coverage since 1991, whereas this is still in its infancy in Denmark. In the search for an explanation for the remaining survival difference, patient delay was a likely candidate. This study compared patient delay and mammography-detection between two national regions. Data on patient delay and mammography were obtained from hospital records from 1989 and 1994, and analysed using Cox proportional hazard analysis of death within the first 5 years, with the factors age, country, delay/mammography detection and established patho-anatomic variables. A comparison of patient delay and mammography detection in 1989 and 1994 showed more mammography-detected tumours in south Sweden and more women with long delay in east Denmark. Mammography detection, but not long patient delay, had a significant effect on the death hazard when adjusting for patho-anatomic risk factors. The hazard ratio was not eliminated in 1989, but in 1994, the hazard ratio between east Denmark and south Sweden was reduced from 1.3 to 1.1. In conclusion, patient delay did not appear to have any effect on 5-year survival when adjusting for patho-anatomic factors, but tumour detection by mammography affected survival favourably and partly explained the survival difference between east Denmark and south Sweden.

On the role of intensity-modulated radiation therapy in radiation oncology

Physicists are critical members of the radiation therapy team, and rightfully so. Therefore, it is not unreasonable that they be acquainted with the broader aspects of the management of patients who receive radiation treatments, as well as the roles played by surgeons, medical oncologists and other members of the treatment team. The spate of recent technical developments openly embraced by medical physicists, many of whom appear unconcerned by questionable benefits and very high costs, leads the authors to believe that this acquaintance is not as widespread as it should be. The present paper provides a brief review of clinical considerations in radiation oncology, statistics for the most prevalent cancers, and how those cancers that account for over 90% of mortality are currently treated. With these data as background, it then considers the extent to which one of the more widely promoted new technologies is likely to impact upon survival. By providing this modicum of perspective, physicists will be in a better position to evaluate these new technologies in more fundamental clinical terms, and thereby enhance their contributions to the overall care of the cancer patient.

Delay in the diagnosis of breast cancer: medico-legal implications

Delay in the diagnosis of breast cancer is an important cause of medical malpractice claims which if trends continue, will threaten healthcare budgets. Most malpractice claims are made by younger women. Delay is most frequently due to the physician failing to be impressed with the clinical findings, or to a false negative mammogram report. Diagnosis of breast cancer is more difficult in younger women, because of the poor sensitivity of diagnostic tests and the high prevalence of benign disease in this age group. Models of tumour growth suggest that the potential to metastasize may be present before the tumour is clinically detectable and that if the growth rate of a given tumour is constant, any clinical delay is a small proportion of the lifespan of the tumour. Patient delay is generally associated with more advanced lesions at presentation, but the effect of delay on survival or what period of delay is significant remains uncertain. Delay in the diagnosis of breast cancer is likely to cause the patient considerable anxiety, especially when the public understands that the aim of mammographic screening is to diagnose breast cancer at an early stage in order to effect a cure. For a plaintiff to successfully claim in court she must prove that she has suffered an injury, and that the injury was the result of negligent medical practice. It is easier to defend a case of delay in diagnosis if the documentation is in order and all the appropriate tests have been performed.

Differences in the quality of care for women with an abnormal mammogram or breast complaint

OBJECTIVE

To examine factors associated with variation in the quality of care for women with 2 common breast problems: an abnormal mammogram or a clinical breast complaint.

DESIGN

Cross-sectional patient survey and medical record review.

SETTING

Ten general internal medicine practices in the Greater Boston area.

PARTICIPANTS

Women who had an abnormal radiographic result from a screening mammogram or underwent mammography for a clinical breast complaint (N = 579).

MEASUREMENTS AND MAIN RESULTS

Three measures of the quality of care were used: (1) whether or not a woman received an evaluation in compliance with a clinical guideline; (2) the number of days until the appropriate resolution of this episode of breast care if any; and (3) a woman's overall satisfaction with her care. Sixty-nine percent of women received care consistent with the guideline. After adjustment, women over 50 years (odds ratio [OR], 1.58; 95% [CI], 1.06 to 2.36) and those with an abnormal mammogram (compared with a clinical breast complaint: OR, 1.75; 95% CI, 1.16 to 2.64) were more likely to receive recommended care and had a shorter time to resolution of their breast problem. Women with a managed care plan were also more likely to receive care in compliance with the guideline (OR, 1.72; 95% CI, 1.12 to 2.64) and have a more timely resolution. There were no differences in satisfaction by age or type of breast problem, but women with a managed care plan were less likely to rate their care as excellent (43% vs 53%, P <.05).

CONCLUSIONS

We found that a substantial proportion of women with a breast problem managed by generalists did not receive care consistent with a clinical guideline, particularly younger women with a clinical breast complaint and a normal or benign-appearing mammogram.

Immediate biopsy versus observation for abnormal findings on mammograms: an analysis of potential outcomes and costs

BACKGROUND

The increased usage of screening mammography has led to an increase in the number of needle localized breast biopsies. The perceived low yield of the biopsies has caused concern about the costs and effectiveness of this procedure. Arguments have centered on what is the appropriate true-positive rate for screening mammography, and which abnormal findings may be observed rather than tested immediately.

METHODS

A decision analysis was done to help answer these questions. Factors evaluated included age of patient at discovery of abnormal finding, the rate of follow-up mammograms eventually requiring biopsy, the potential effects of tumor-doubling time on increasing the stage of disease, quality-of-life issues, and costs.

RESULTS

For an average 50-year-old woman the quality-adjusted life expectancy (QALE) was longer for immediate biopsy by 0 to 3 years, depending on the assumptions on tumor-doubling time; however, immediate biopsy increased the cost per patient from $700 to $900. The QALE was also superior for immediate biopsy if more than 30% of follow-up mammograms required biopsy, and immediate biopsy was more cost effective if more than 36% of follow-up mammograms required biopsy. Patient age did not affect the superiority of immediate biopsy over observation, although quality-of-life issues did.

CONCLUSIONS

Those lesions with a greater than 20% to 30% probability of being malignant, or lesions with potentially short doubling times, should undergo immediate biopsy. Lesions judged to be at lower risk may be observed for 6 months. Either of these recommendations should be adjusted depending on an individual patient's quality-of-life concerns.

Prognostic factors and the curability of breast cancer

Over the years three different concepts regarding the cure of treated breast cancer have emerged. These are clinical cure, personal cure and statistical cure. The latter is the most accurate estimate of the curability of a disease which is presumed to be fatal unless treated. Statistical cure is the elimination of the hazard of death in a treated group compared with an age-matched control population. When statistical cure is studied in patients treated for early breast cancer, it is clear that breast cancer is an incurable disease. The expected gains from the relatively recent introduction of adjuvant therapy are too small to alter this concept. The significance of prognostic factors in a disease deemed to be incurable therefore requires re-examination. The conventional prognostic factors of tumour size, nodal status and a combination of those two in staging systems significantly discriminates in terms of survival in the short term. However, when the characteristics of long-term survivors are examined, neither tumour size nor nodal status discriminates effectively. If this is the case, then we need to reconsider novel treatment strategies which have been introduced in the hope of increasing the curability of the disease and the selection for those treatment strategies of patients using the conventional prognostic factors of tumour size or nodal involvement.

Evolving strategies for the management of non-palpable breast abnormalities

Increased public and professional awareness has resulted in more women obtaining mammograms. As a result, the surgeon is often called on to diagnose and treat occult breast lesions. The development of new diagnostic modalities has changed the way such breast lesions are approached. Management decisions are made in the context of new pressures applied by the growing managed care imperative and increased mediocolegal exposure. In this review, we establish guidelines for the management of non-palpable breast abnormalities that place the welfare of the patient first.

The timely diagnosis of breast cancer. Principles of risk management for primary care providers and surgeons

Alleged delay in the diagnosis of breast cancer is one of the most common reasons for medical malpractice claims in the United States, accounting for the largest indemnity payments of any single medical condition. Although the diagnosis of breast cancer can be challenging and sometimes difficult, principles of management exist to assist health providers in pursuing a resolution of any breast complaint. Studies have shown that when litigation is pursued for alleged failure to diagnose breast cancer, multiple specialists are named in the suit. In most cases, patients filing claims of alleged failure to diagnose breast cancer are premenopausal, while the majority of women diagnosed with breast cancer are postmenopausal. This reflects, in part, the challenge of diagnosing the disease in women who have difficult clinical exams to interpret, as well as dense parenchyma on mammograms, which decreases the sensitivity of the radiograph interpretation. Principles of risk management to avoid a delay in diagnosis include (1) pursuing every breast complaint to resolution, (2) following breast cancer screening guidelines, (3) establishing an office tracking system for breast cancer screening reminders, (4) tracking results of all mammograms and follow-up studies ordered, (5) referring premenopausal women for the evaluation of any breast mass that persists through a menstrual cycle, (6) considering any asymmetrical breast finding as a cause for concern, (7) referring every woman with a breast finding on physical examination for consultation, regardless of the mammogram report, and (8) carefully documenting patient history, physical exam findings, clinical impression, and follow-up plans.

Value of preoperative bone and liver scans and alkaline phosphatase in the evaluation of breast cancer patients

We reviewed the results of 133 bone scans and 63 liver scans (computed tomography, liver-spleen radionuclide scan, or ultrasonography) obtained for the preoperative evaluation of breast cancer patients. Information on the preoperative staging of breast cancer (TNM classification) was available in 131 of 133 patients. Bone scans had a low preoperative yield as only 4 of 133 patients (3%) had a positive bone scan that correlated with the results of plain films. Only 1 of 63 patients had a liver scan suggestive of possible metastasis. We also found that the alkaline phosphatase level was not a good predictor of bone or liver metastases in breast cancer patients. In 103 patients with normal bone scans, the majority (54%) had elevated alkaline phosphatase levels; conversely, 9 of 30 patients (30%) with abnormal scans had normal alkaline phosphatase levels. Furthermore, 51 of 63 patients (81%) with elevated alkaline phosphatase levels had normal liver scans. Approximately $74,000 was spent on these liver and bone scans.

Legal issues in managing breast disease

The impact of legal issues in breast cancer care reflects the significance of breast cancer as a health concern of women. Breast cancer has emerged as a leading liability risk for primary care physicians, with most cases focusing on delayed diagnosis. Although the clinical impact of delayed diagnosis of breast cancer is often controversial, physicians should strive to diagnose breast cancer as early as possible in the natural history of the disease. No currently available data suggest that a delay of less than 2 months between the onset of symptoms and diagnosis or treatment adversely influences outcome. Techniques that help physicians reduce the liability risks associated with breast cancer care include patient education, adequate documentation and follow-up, and referral or consultation in high-risk situations.