Postmastectomy radiation: a modest benefit prevails for high risk patients

Postmastectomy radiation therapy: an overview for the practicing surgeon

Locoregional control of breast cancer is the shared domain and responsibility of surgeons and radiation oncologists. Because surgeons are often the first providers to discuss locoregional control and recurrence risks with patients and because they serve in a key gatekeeping role as referring providers for radiation therapy, a sophisticated understanding of the evidence regarding radiotherapy in breast cancer management is essential for the practicing surgeon. This paper synthesizes the complex and evolving evidence regarding the role of radiation therapy after mastectomy. Although substantial evidence indicates that radiation therapy can reduce the risk of locoregional failure after mastectomy (with a relative reduction of risk of approximately two-thirds), debate persists regarding the specific subgroups who have sufficient risks of residual microscopic locoregional disease after mastectomy to warrant treatment with radiation. This paper reviews the evidence available to guide appropriate referral and patient decision making, with special attention to areas of controversy, including patients with limited nodal disease, those with large tumors but negative nodes, node-negative patients with high risk features, patients who have received systemic chemotherapy in the neoadjuvant setting, and patients who may wish to integrate radiation therapy with breast reconstruction surgery.

Clinical practice guidelines for the care and treatment of breast cancer: 15. Treatment for women with stage III or locally advanced breast cancer

OBJECTIVE

To define the optimal treatment for women with stage III or locally advanced breast cancer (LABC).

EVIDENCE

Systematic review of English-language literature retrieved from MEDLINE (1984 to June 2002) and CANCERLIT (1983 to June 2002). A nonsystematic review of the literature was continued through December 2003.

RECOMMENDATIONS

The management of LABC requires a combined modality treatment approach involving surgery, radiotherapy and systemic therapy. Systemic therapy: chemotherapy. Operable tumours. Patients with operable stage IIIA disease should be offered chemotherapy. They should receive adjuvant chemotherapy following surgery, or primary chemotherapy followed by locoregional management. Chemotherapy should contain an anthracycline. Acceptable regimens are 6 cycles of FAC, CAF, CEF or FEC. Taxanes are under intense investigation. Inoperable tumours. Patients with stage IIIB or IIIC disease, including those with inflammatory breast cancer and those with isolated ipsilateral internal mammary or supraclavicular lymph-node involvement, should be treated with primary anthracycline-based chemotherapy. Acceptable chemotherapy regimens are FAC, CAF, CEF or FEC. Taxanes are under intense investigation. Patients with stage IIIB or IIIC disease who respond to primary chemotherapy should be treated until the response plateaus or to a maximum of 6 cycles (minimum 4 cycles). Patients with stage IIIB disease should then undergo definitive surgery and irradiation. The locoregional management of patients with stage IIIC disease who respond to chemotherapy should be individualized. In patients with stage IIIB or IIIC disease who achieve maximum response with fewer than 6 cycles, further adjuvant chemotherapy can be given following surgery and irradiation. Patients whose tumours do not respond to primary chemotherapy can be treated with taxane chemotherapy or can proceed directly to irradiation followed by modified radical mastectomy, if feasible. Systemic therapy: hormonal therapy. Operable and inoperable tumours. Tamoxifen for 5 years should be recommended to pre- and postmenopausal women whose tumours are hormone responsive. Locoregional management. Operable tumours. Patients with stage IIIA disease should receive both modified radical mastectomy (MRM) and locoregional radiotherapy if feasible. They may be managed with MRM followed by chemotherapy and locoregional radiotherapy, or chemotherapy first followed by MRM and locoregional radiotherapy. Breast-conserving surgery is currently not a standard approach. Locoregional radiotherapy should be delivered to the chest wall and to the supraclavicular and axillary nodes. The role of internal mammary irradiation is unclear. Inoperable tumours. Patients with stage IIIB disease who respond to chemotherapy should receive surgery plus locoregional radiotherapy. The locoregional management of patients with stage IIIC disease who respond to chemotherapy is unclear and should be individualized. Patients whose disease remains inoperable following chemotherapy should receive locoregional radiotherapy with subsequent surgery, if feasible.

VALIDATION

The authors' original text was revised by members of the Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer. Subsequently, feedback was provided by 9 oncologists from across Canada. The final document was approved by the steering committee.

SPONSOR

The Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer was convened by Health Canada. Completion date: December 2003.

Occult breast cancer and axillary mass

Occult breast cancer presenting with axillary metastases is an unusual presentation and can be a diagnostic and therapeutic challenge. A comprehensive work-up, including mammogram, sonogram, magnetic resonance imaging, and even pathologic examination of the mastectomy specimen may not disclose the primary tumor in up to one third of patients. Traditionally, occult breast cancer is treated with total mastectomy and axillary dissection, but accumulating data suggest that primary breast irradiation following axillary dissection may provide an equivalent survival with the advantage of breast conservation. Occult breast cancer patients are eligible for adjuvant chemotherapy and radiation as stage II/ III node-positive patients would be treated. Overall, the prognosis for occult breast cancer is equivalent to or slightly better than staged counterparts with detectable primary breast tumors.

A cost-outcome analysis of adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients

PURPOSE

To calculate cost-effectiveness and cost-utility ratios for adjuvant postmastectomy locoregional radiotherapy in premenopausal node-positive breast cancer patients and to place these ratios in the context of generally accepted medical expenditures.

MATERIALS AND METHODS

A spreadsheet-based activity costing model using 1997 Canadian (cdn) capital, operating, and administrative costs has been used to identify, from the institutional perspective, the incremental cost of adding radiotherapy to surgery and chemotherapy for this group of patients. Outcome data were derived from two recently published clinical trials and were converted to discounted incremental life years and quality-adjusted life years gained. Recommended health economics principles were employed in the quantification of both costs and outcomes, and a sensitivity analysis was performed. Three referenced publications provide a context within which to evaluate the calculated cost-effectiveness and cost-utility ratios.

RESULTS

The incremental cost of adjuvant radiotherapy for this group of patients is calculated to be approximately $7,000cdn in 1997 Canadian dollars and in the Canadian socialized health-care environment. Based on published work the discounted incremental outcome benefit is calculated to be 0.5 life years or 0.45 quality-adjusted life years at ten years. Thus, cost effectiveness and cost-utility ratios are estimated to be $14,000cdn and $15,600cdn, respectively.

CONCLUSION

Within the context of generally accepted medical expenditures, adjuvant postmastectomy locoregional radiotherapy for premenopausal node-positive breast cancer patients would be regarded as a cost-effective treatment strategy.

Adjuvant radiotherapy in breast cancer--the treatment of lymph node areas

Adjuvant radiotherapy decreases the risk of locoregional recurrences threefold, according to the results of many randomized trials and overviews. In patients treated with total mastectomy, the risk of local recurrence is mainly related to the number of involved axillary nodes, i.e. about 25%, 35% and 55% at 10 years when 1-3, 4-9 and 10 or more nodes are involved, respectively. In contrast, at 10 years, less than 15% of patients with negative axillary nodes relapse locally. The effect of adjuvant radiotherapy on distant metastases and overall survival is a controversial issue. On the one hand, recent results are compatible with the existence of a mechanism of secondary dissemination generated from locoregional tumor nests. The beneficial effect of radiotherapy can be observed whether with or without adjuvant systemic treatment. On the other hand, a deleterious late toxic effect, mainly cardiac, has also been shown. The importance of improvements in radiation techniques and quality assurance to obtain a positive balance in terms of overall survival is emphasized.

Management of axillary lymph nodes in breast cancer: a national patterns of care study of 17,151 patients

OBJECTIVE

To determine the rates of axillary lymph node dissection (ALND) and axillary irradiation (AI) in patients with breast cancer and to identify the factors influencing them.

SUMMARY BACKGROUND DATA

Routine performance of ALND in the treatment of breast cancer has become controversial. AI has been proposed as an alternative to ALND, and it has been suggested that AI in addition to ALND may decrease local failure in high-risk patients.

METHODS

A joint study was conducted by the Commission on Cancer of the American College of Surgeons and the American College of Radiology. A total of 17,151 patients with stage I and II breast cancer treated at 819 institutions in 1994 were studied.

RESULTS

A total of 15,992 patients underwent ALND (93%). The mean ages of patients who did and did not undergo ALND were 60.4 and 73.0 years. Univariate analysis demonstrated significantly decreased rates of ALND for women age 70 or older (86% vs. 97%), patients with clinical T1 a tumors (81% vs. 93%), grade I histology (90% vs. 95%), and patients with favorable tumor types (88% vs. 94%). The ALND rate did not vary between palpable and nonpalpable tumors. Multivariate analysis of variables affecting the rate of ALND identified type of surgery, age, tumor size, histology, and payer status as significant. A total of 889 patients received AI. Patients not undergoing ALND were more likely to receive AI (10% vs. 5%). A total of 1.6% of patients with no lymph node metastasis underwent AI, 8.9% of those with one to three positive nodes underwent AI, 24.0% of those with four to nine positive lymph nodes underwent AI, and 29.9% of those with > or = 10 positive lymph nodes underwent AI. Multivariate analysis of variables affecting the proportion of patients who received AI and had undergone ALND identified nodal status and type of surgery as significant.

CONCLUSIONS

Axillary lymph node dissection continues to be routinely applied in the treatment of breast cancer, and AI remains underused in patients at high risk for local regional relapse.

Postmastectomy radiotherapy: randomized trials

Postmastectomy radiotherapy decreases threefold the risk of locoregional recurrences according to the results of many randomized trials and overviews. This risk is mainly related to the number of involved axillary nodes (ie, about 25%, 35%, and 55% at 10 years when 1 to 3, 4 to 9, and 10 or more nodes are involved). In contrast, at 10 years, fewer than 15% of patients with negative axillary nodes relapse locally. The effect of postmastectomy radiotherapy on distant metastases and overall survival is a controversial issue. On the one hand, results are compatible with the existence of a mechanism of secondary dissemination generated from locoregional tumor nests. The beneficial effect of radiotherapy may be observed in the absence or presence of adjuvant systemic treatment. On the other hand, a deleterious late toxic, mainly cardiac, effect of radiation has also been shown. This point emphasizes the importance of radiation technique and quality to obtain a positive balance in terms of overall survival.

Assessing the cost-effectiveness of postmastectomy radiation therapy

PURPOSE

To assess the cost-effectiveness of postmastectomy local-regional radiation therapy (RT) for patients with breast cancer with regard to local-regional relapse (LRR) and quality-adjusted life years (QALY).

METHODS AND MATERIALS

Data from the literature are used to estimate the risk of LRR, and the impact of RT on the risk of LRR and survival. The risk of LRR is related linearly to the number of positive axillary nodes 1% rate of LRR = 10 + (4 x number of positive nodes)]. RT reduces the risk of LRR by 67%. LRRs are treated with excision or biopsy followed by RT; half being controlled locally and half receiving additional salvage surgery and chemotherapy. Absolute improvements in 10-year overall survival due to RT are assumed to vary between 1 and 12%; and accrue linearly during the initial 10-year follow-up period. Professional and technical charges are used as a surrogate for costs. Money spent and benefits recognized in future years are discounted to 1997 values using a 3% annual rate. Quality factors are used to adjust for treatment, disease, and toxicity status.

RESULTS

The cost per LRR prevented with the addition of routine postmastectomy RT is highly dependent upon the number of positive axillary nodes and ranges from $100,000-$200,000 for patients with 0-2 nodes, and $25,000-$75,000 for > or = 4 nodes. The cost per QALY gained at 10 years is $10,000-$110,000 for survival benefits > or = 3%.

CONCLUSIONS

The cost per LRR prevented decreases with increasing numbers of positive axillary nodes. There is not a sharp cutoff at the < or = 3 vs. > or = 4 lymph node number, suggesting that using this cutoff for recommending or not recommending RT following mastectomy is not economically logical. The cost per QALY of $10,000-$100,000 compares favorably to that of other accepted medical procedures. Modest changes in the quantitative assumptions do not qualitatively alter the results. Concerns regarding costs should not generally preclude the use of postmastectomy RT.

[Influence of locoregional irradiation on local control and survival in breast cancer]

Locoregional control is a crucial step in the achievement of breast cancer cure. In ductal carcinoma in situ, breast irradiation significantly reduces the rates of local recurrence whatever the histological subtypes, as demonstrated by the NSABP-B17 trial (25.8% of local recurrences without radiotherapy vs. 11.4% with radiotherapy). In infiltrating breast carcinomas, complementary breast irradiation has been shown to significantly improve the local control and slightly the overall survival in five randomized trials. Following mastectomy, locoregional irradiation clearly reduces the chest wall and nodal relapse rates, especially in case of lesions more than 5 cm or with nodal involvement and/or large lymphatic or vascular emboli. Two recent randomized trials confirmed the benefit of well-adapted locoregional irradiation in all subgroups, especially in patients with one to three axillary involved nodes. In the Danish trial (including premenopausal high-risk women), radiotherapy reduced locoregional relapses from 32 to 9% (p < 0.001) and increased the 10-year survival rate from 45 to 54% (p < 0.001). In the Canadian trial, locoregional relapse rate decreased from 25 to 13% and the 10-year survival rate increased from 56 to 65%. The meta-analysis published in 1995 by the EBCTCG showed only a modest benefit due to locoregional irradiation in breast cancer. However, when small or old trials were excluded due to imperfect methodology or inadequate irradiation techniques, the benefit of modern radiotherapy became much more evident in a population of 7,840 patients. Locoregional irradiation appears to be able to reduce the risk of metastatic evolution occurring after local or nodal relapse and must be integrated in a multidisciplinary strategy. Treatment toxicity (especially toxicity due to irradiation of internal mammary nodes) is of special concern, as anthracycline-based chemotherapy is prescribed more often. The use of a direct field, with at least 60% of the dose delivered by electrons alternating with photons is recommended to protect the heart and lungs.