Breast imaging. A critical aspect of breast conserving treatment

Practice Guideline for the Breast Conservation Therapy in the Management of Invasive Breast Carcinoma

This is the second of two articles reprinted with permission from: Practice guideline for breast conservation therapy in the management of invasive breast carcinoma. In: Practice Guidelines and Technical Standards. Reston, VA: American College of Radiology;2006:443-468. In this reprinting "G" in Section IV is available in the Online version only. For Section VI please refer to the first publication of ductal carcinoma in-situ (J Am Coll Surg 2007:205:145-161). Parts of this article have been shortened for brevity. The full article is available through the American College of Radiology. The American College of Radiology, with more than 30,000 members, is the principal organization of radiologists, radiation oncologists, and clinical medical physicists in the United States. The College is a nonprofit professional society whose primary purposes are to advance the science of radiology, improve radiologic services to the patient, study the socioeconomic aspects of the practice of radiology, and encourage continuing education for radiologists, radiation oncologists, medical physicists, and persons practicing in allied professional fields. The American College of Radiology will periodically define new practice guidelines and technical standards for radiologic practice to help advance the science of radiology and to improve the quality of service to patients throughout the United States. Existing practice guidelines and technical standards will be reviewed for revision or renewal, as appropriate, on their fifth anniversary or sooner, if indicated. Each practice guideline and technical standard, representing a policy statement by the College, has undergone a thorough consensus process in which it has been subjected to extensive review, requiring the approval of the Commission on Quality and Safety as well as the ACR Board of Chancellors, the ACR Council Steering Committee, and the ACR Council. The practice guidelines and technical standards recognize that the safe and effective use of diagnostic and therapeutic radiology requires specific training, skills, and techniques, as described in each document. Reproduction or modification of the published practice guideline and technical standard by those entities not providing these services is not authorized.

What is achieved by mammographic surveillance after breast conservation treatment for breast cancer?

BACKGROUND

After breast conservation surgery for breast cancer, patients are followed up by regular clinical examination and mammography, at intervals which vary according to local practice. However, the optimum interval remains unclear with current guidelines suggesting mammography should be carried out every 1 to 2 years. This study has investigated this aspect and, in particular, whether mammography or clinical examination or both allowed an early detection of recurrence of the disease in the conserved breast.

METHODS

A total of 695 patients who had undergone breast conservation surgery were identified from a database of prospectively recorded data during the period 1990 to 1995. Clinical examination and annual mammography were performed in accordance with local protocol. The results of clinical examination, mammography, and local recurrence rates were evaluated.

RESULTS

A total of 2,181 mammograms were undertaken in the 695 patients studied. Local recurrence of disease in the conserved breast occurred in 21 patients (3%), at a mean follow-up of 3.5 years. The first identification of tumor recurrence was by clinical examination in 11 patients with local recurrence, and by the surveillance mammography in the other 10 patients with local recurrence. Overall, mammography detected the local recurrence in 13 of 20 (65%) patients who underwent this examination. In the other patients, the recurrence was detected on clinical examination only. In addition, in 52 patients, mammography was falsely positive, giving a false positive rate of 2.3%. Contralateral cancers in the opposite breast were detected in 2 patients.

CONCLUSIONS

The detection of local disease after breast conservation surgery requires both clinical examination and mammography. In the context of our follow-up policy, in 52% of patients with local recurrence, this was first identified by clinical examination. Disease recurrence was identified in the other 48% of patients by mammographic surveillance. Overall, mammography will identify or confirm local recurrence in two thirds of women. However, in a small number of cases (2.3% in our series) mammography will give false positive results. New imaging modalities to assist in the diagnosis of local recurrence of disease after breast conservation surgery are required.

Breast imaging: from 1965 to the present

The current state of the art for breast imaging is reviewed in comparison with the methods of practice commonly in use 25-35 years ago to demonstrate the most important advances that have taken place in imaging techniques, operational considerations, interpretive approaches, and interventional procedures. Since 1965, breast imaging has progressed from the simple assessment of breast disease in a selected small number of symptomatic women to the comprehensive evaluation of both breast health and disease in a substantial percentage of all women aged 40 years and older. In the process, breast imaging has become an established radiologic subspecialty that accounts for at least 10% of all examinations performed by radiologists. Indeed, mammography now is the most common imaging examination that directly results in the reduction of mortality from disease.

A controlled evaluation of tuned-aperture computed tomography applied to digital spot mammography

The purpose of this work was to compare the detection accuracy of 3-dimensional (3D) modalities of tuned-aperture computed tomography (TACT) with that of conventional 2-dimensional (2D) digital spot mammograms. A standardized mammographic phantom was placed beneath cadaveric breast tissues of varying densities. Five radiologists were asked to detect as many objects (specks, fibers, and low-contrast masses) as possible from 90 displays in a controlled and factorially balanced multivariate experiment. Radiographic exposure was varied systematically, and projections were averaged to ensure stochastic comparability. Scores were weighted to eliminate task-specific bias and were analyzed by multivariate analyses of variance. All display modalities based on the linear application of the 3D TACT reconstruction method yielded significantly higher detection scores for all tasks than did conventional 2D digital spot mammography, which served as the scientific control modality. This effect was found to be statistically significant (P < .001) in spite of significant variations between tissues (P < .001), observers (P < .001), and exposures (P < .01). TACT may be a promising alternative or enhancement to conventional 2D digital mammography for tasks well simulated by this experimental design.

Effect of radiotherapy on the interpretation of routine follow-up mammography after conservative breast surgery: a randomized study

Radiotherapy after conservative surgery causes fat necrosis, fibrosis, skin thickening and other parenchymal distortion of the breast. The interpretation of a mammogram of the irradiated breast may therefore be difficult. We studied the effect of radiotherapy on the interpretation of the routine mammography used in the follow-up of breast cancer patients. A total of 144 low-risk breast cancer patients were randomized to radiotherapy or to no further treatment after conservative surgery. The first routine follow-up mammography was performed 18 months after surgery and every 18 months after that. The number of mammography examinations was estimated per patient and per follow-up year. The number of extra diagnostic tests and the occurrence of positive findings were assessed per mammography session and per follow-up year. Further diagnostic tests prompted by difficulties in interpreting the mammogram were performed to an extent of 0.19 per mammography examination in the radiotherapy group and of 0.15 in the non-radiotherapy group, i.e. 1.3 times more often. Findings that turned out to be negative at confirmation were 2.0 times (P< 0.05) more common in the radiotherapy group. These false-positive findings were more common in the radiotherapy group than in the surgery group and only shortly after treatment. Mammography is more difficult to interpret after radiotherapy than after conservative surgery alone, especially shortly after treatment, and more often involves extra diagnostic tests and findings that will be negative at confirmation.

Ductal carcinoma in situ. Part 2: Treatment

Several dilemmas exist when treating a patient with ductal carcinoma in situ (DCIS): the high rate of inter-observer variation for pathologists who must diagnose these tumours; the potential for over- and under-treatment; and the uncertainty about the best way to inform a patient who must often make a decision between breast conservation and mastectomy. Mastectomy is nearly 100% curative, is expedient, but may represent over-treatment for many women, particularly those with asymptomatic mammographically detected lesions. Axillary dissection is not recommended as a routine except for patients with lesions over 5 cm in whom the risk of micro-invasion and lymph node involvement increases. Conservative surgery (CS) alone is associated with a local recurrence rate of approximately 20%, and half of these recurrences (10% overall) are invasive, with a potential long-term cure rate of at least 90%. The addition of radiation to CS reduces the risk of local recurrence to approximately 10%, half of these recurrences (5%) are invasive for a potential long-term cure rate of 95%. Several randomized trials comparing CS with or without radiation therapy (RT) are in progress. The factors that increase the rate of local recurrence after CS alone for DCIS include close or involved margins, and the presence of necrosis or high-grade tumours. Patients with these features should have radiation therapy if breast conservation is preferred. Patients with low-grade tumours (without necrosis) up to 15 mm, with clear margins of at least 10 mm, who agree to be closely observed may be good candidates for CS alone. A critical review of the literature is presented.

Conservative therapy of breast cancer in Queensland

PURPOSE

Primary radiation therapy following breast-conserving surgery has been an accepted alternative to mastectomy in Europe and North America for many years. In Australia, however, the history of breast conservation for early invasive breast cancer is much shorter. The purpose of this study was to evaluate the results of breast conservation in a state-wide Australian radiotherapy service.

METHODS AND MATERIALS

Between January 1982 and December 1989, 512 patients were treated with primary radiation therapy after breast conserving surgery. This analysis is based on a review of these patients, all of whom had Stage I or II breast cancer.

RESULTS

With a median follow-up of 50 months, the 5-year actuarial rate of overall survival was 84% and disease-free survival was 80%. There have been 22 isolated local recurrences in the breast. The time to an isolated breast recurrence ranged from 12 to 83 months (median, 26 months). The 5-year actuarial rate of an isolated breast recurrence was 4%. The recurrence rate was higher for patients with involved margins (15% vs. 2%, p < 0.01). Local recurrence was also more likely in the presence of extensive ductal carcinoma in situ (DCIS), as opposed to no extensive DCIS (10% vs. 2%, p < 0.01).

CONCLUSION

These results affirm that primary radiation therapy after breast conserving surgery in Queensland, has been given with a low rate of local recurrence, comparable to that obtained in other centers.

Non-surgical management of early breast cancer in the United Kingdom: follow-up. Clinical Audit Sub-committee of the Faculty of Clinical Oncology, Royal College of Radiologists, and the Joint Council for Clinical Oncology

Follow-up of operable breast cancer patients takes up a significant proportion of British oncologists' time, with 90% seeing 5-50 patients each week. Procedures vary greatly, but, in patients treated by surgery and radiotherapy, care is usually shared, with alternating visits to see each team. Currently, the general practitioner has sole responsibility for follow-up in less than 3% of patients. They tend to be followed up in general, rather than specialist, clinics. There is almost universal agreement that routine blood tests, radiographs and scans are not indicated as part of routine follow-up, but the role of mammography in evaluating an irradiated breast remains a source of debate. Just over a half of the oncologists surveyed order baseline mammography of both treated and contralateral breasts, usually between 6 and 12 months after local excision and radiotherapy, with further follow-up 1-3-yearly thereafter. Ten per cent of the participating oncologists never suggest follow-up mammography. Patients tend to be followed in oncology clinics at 3-4-monthly intervals for the first 2 years, 6-monthly in the third and fourth years and, thereafter, yearly. Fifteen per cent of oncologists discharge patients at 5 years, with the discharge rate rising to 43% at 10 years; around one-third modify follow-up according to the age of the patient. The aims of follow-up were seen to include detection of curable disease, but other goals were perceived as equally important (e.g. detection of iatrogenic problems, audit, counselling, education and the provision of early palliation of incurable and metastatic disease. Breast cancer is no longer seen as an absolute contraindication to either pregnancy or the use of hormone replacement therapy (HRT); however, oncologists are uncertain about the appropriate use of HRT, either alone or with tamoxifen. This audit highlights a number of research areas: the identification of the appropriate site and skill-mix for follow-up of patients; clarification of the aims and attitudes to follow-up by both patients and health care professionals; the use of breast imaging; and the role of HRT.

Scar formation after breast-conserving surgery for cancer. Sir Charles Gairdner Hospital Breast Cancer Group

A study of surgery for breast cancer was performed to examine the influence of haematoma formation and radiotherapy on the development of mammographically detected scars. Fifty-nine women undergoing lumpectomy and radiotherapy were studied. Sixteen had mammographic scars 12 months after surgery. There was a correlation between postoperative haematoma formation and scarring (P = 0.03) but not between tumour size and scarring. The type of radiation therapy did not influence scar formation.

Patient selection for treatment with conservative surgery and radiation therapy

There is now general agreement that treatment with conservative surgery and radiation therapy yields survival equal to mastectomy with the advantage of organ preservation for properly selected patients. When competently performed, such treatment gives highly satisfactory cosmetic results and acceptably low rates of local tumor recurrence. However, there remain numerous controversies concerning patient selection for this treatment option. The factors involved in patient selection may be grouped into three categories: patient factors; clinical factors; and pathologic factors. This article reviews their use. Because breast cancer has a long natural history, long follow up of patients is required for ultimate proof of the relative merits of different selection or treatment policies. However, due to the increasing numbers of patients being treated with conservative surgery and radiotherapy, it appears likely that many of these questions will be answered within the next decade.

Surgical considerations in needle localization procedures

There is an increasing need for needle localization biopsies. Cancers so detected are usually at an earlier stage and should result in an increased cure rate. The surgeon involved in these procedures should, of necessity, be proficient in evaluating mammographic abnormalities, since there is considerable variation in the way they are reported by various radiologists. Localization can be accomplished with various hooked wires or dye, but accuracy of placement is more important than the method used and this point is well understood by cooperative radiologists. Since 70-80% of these lesions will be benign, cosmesis should be kept in mind. Incisions should be placed centrally, if possible, and the volume excised should be minimal and not lead to deformity. When poorly localized, excision of these lesions can be a trying experience for the experienced surgeon.