Second malignant neoplasms in operable carcinoma of the breast

Leukemia risk after adjuvant treatment of early breast cancer

Modern cancer treatment has substantially increased the survival and curability of patients with various malignancies. Therefore, favorable prognosis mandates for the evaluation of long-term complications of treatment. Since the late 1970s, adjuvant combination chemotherapy for operable breast cancer has come into widespread use. Several recent studies have estimated the risk of acute myeloid leukemia associated with these regimens. The purpose of this analysis is to discuss the risk of leukemia after early breast cancer therapy, the types of leukemia, and the relationship between the risk of leukemia and treatment with different cytotoxic agents (alkylating agents, antimetabolities, topoisomerase II inhibitors, dose-dense therapy, high-dose therapy and growth factor use) and radiotherapy.

Second cancers after breast cancer treatment

Breast irradiation, adjuvant chemotherapy, and tamoxifen are associated with an increased risk of second cancers that may manifest decades after treatment. Although very small, it is nonetheless important for clinicians and women to be aware of and to recognize the risk. Postmastectomy irradiation is associated with a slight increase in the risk of developing a sarcoma or lung cancer after a latency period of more than 10 years. However, the majority of information on radiation-associated cancers is derived from large tumor registries, which reflect outdated radiation treatment practices. Modern treatment approaches, which use lower fraction size (or dose) and limit the exposure of surrounding normal tissue to radiation, are less likely to cause radiation-associated cancers. Adjuvant chemotherapy is not associated with any detectable increased risk of solid tumors beyond that which occurs as the population ages. However, alkylating agents, such as cyclophosphamide, and the topoisomerase II inhibitors, doxorubicin and epirubicin, are associated with two types of cytogenetically distinct leukemias after adjuvant chemotherapy. The absolute risk of developing leukemia is lower by orders of magnitude than the improvement in breast cancer mortality that results from adjuvant chemotherapy. Tamoxifen is associated with a two- to threefold increase in the risk of developing endometrial cancer, or about 80 excess cases per 10,000 treated women at 10 years. The benefits of adjuvant therapy outweigh the risks of developing second cancers. Additional studies are needed to more precisely identify patients who are or are not likely to benefit from adjuvant therapy, and individual host and treatment factors that influence the development of second cancer.

Acute myeloid leukemia and myelodysplastic syndrome after doxorubicin-cyclophosphamide adjuvant therapy for operable breast cancer: the National Surgical Adjuvant Breast and Bowel Project Experience

PURPOSE

We reviewed data from all adjuvant NSABP breast cancer trials that tested regimens containing both doxorubicin (A) and cyclophosphamide (C) to characterize the incidence of subsequent acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

MATERIALS AND METHODS

Six complete NSABP trials have investigated AC regimens (B-15, B-16, B-18, B-22, B-23, and B-25). Six distinct AC regimens have been tested and are distinguished by differences in cyclophosphamide intensity and cumulative dose and by the presence or absence of mandated prophylactic support with growth factor and ciprofloxacin. In all regimens, A was given at 60 mg/m(2) q 21 days x 4. C was given as follows: 600 mg/m(2) q 21 days x 4 ("standard AC"); 1,200 mg(2) q 21 days x 2; 1,200 mg/m(2) q 21 days x 4; 2,400 mg/m(2) q 21 days x 2; and 2,400 mg/m(2) q 21 days x 4. Occurrence of AML/MDS was summarized by incidence per 1,000 patient-years at risk and by cumulative incidence. Rates were compared across regimens, by age, and by treatment with or without breast radiotherapy.

RESULTS

The incidence of AML/MDS was sharply elevated in the more intense regimens. In patients receiving two or four cycles of C at 2,400 mg/m(2) with granulocyte colony-stimulating factor (G-CSF) support, cumulative incidence of AML/MDS at 5 years was 1.01% (95% confidence interval [CI], 0.63% to 1.62%), compared with 0.21% (95% CI, 0.11% to 0.41%) for patients treated with standard AC. Patients who received breast radiotherapy experienced more secondary AML/MDS than those who did not (RR = 2.38, P=.006), and the data indicated that G-CSF does may possibly also be independently correlated with increased risk.

CONCLUSION

AC regimens employing intensified doses of cyclophosphamide requiring G-CSF support were characterized by increased rates of subsequent AML/MDS, although the incidence of AML/MDS was small relative to that of breast cancer relapse. Breast radiotherapy appeared to be associated with an increased risk of AML/MDS.

Secondary leukemia or myelodysplastic syndrome after treatment with epipodophyllotoxins

PURPOSE

The incidence of secondary leukemia after epipodophyllotoxin treatment and the relationship between epipodophyllotoxin cumulative dose and risk are not well characterized. The Cancer Therapy Evaluation Program (CTEP) of the National Cancer Institute (NCI) has developed a monitoring plan to obtain reliable estimates of the risk of secondary leukemia after epipodophyllotoxin treatment.

METHODS

Twelve NCI-supported cooperative group clinical trials were identified that use epipodophyllotoxins at low (<1.5 g/m2 etoposide), moderate (1.5 to 2.99 g/m2 etoposide), or higher (> or =3.0 g/m2 etoposide) cumulative doses. Cases of secondary leukemia (including treatment-related myelodysplastic syndrome) occurring on these trials have been reported to CTEP, as has duration of follow-up for all patients, thereby allowing calculation of cumulative 6-year incidence rates of secondary leukemia for each etoposide dose group.

RESULTS

The calculated cumulative 6-year risks for development of secondary leukemia for the low, moderate, and higher cumulative dose groups were 3.3%, (95% upper confidence bound of 5.9%), 0.7% (95% upper confidence bound of 1.6%), and 2.2%, (95% upper confidence bound of 4.6%), respectively.

CONCLUSION

Within the context of the epipodophyllotoxin cumulative dose range and schedules of administration encompassed by the monitoring plan regimens, and within the context of multiagent chemotherapy regimens that include alkylating agents, doxorubicin, and other agents, factors other than epipodophyllotoxin cumulative dose seem to be of primary importance in determining the risk of secondary leukemia. Data obtained by the CTEP secondary leukemia monitoring plan support the relative safety of using epipodophyllotoxins according to the therapeutic plans outlined in the monitored protocols.

Risk of leukemia after chemotherapy and radiation treatment for breast cancer

BACKGROUND

Few studies have evaluated the late effects of adjuvant chemotherapy for breast cancer. Moreover, the relation between the risk of leukemia and the amount of drug given and the interaction of chemotherapy with radiotherapy have not been described in detail.

METHODS

We conducted a case-control study in a cohort of 82,700 women given a diagnosis of breast cancer from 1973 to 1985 in five areas of the United States. Detailed information about therapy was obtained for 90 patients with leukemia and 264 matched controls. The dose of radiation to the active marrow was estimated from individual radiotherapy records (mean dose, 7.5 Gy).

RESULTS

The risk of acute nonlymphocytic leukemia was significantly increased after regional radiotherapy alone (relative risk, 2.4), alkylating agents alone (relative risk, 10.0), and combined radiation and drug therapy (relative risk, 17.4). Dose-dependent risks were observed after radiotherapy and treatment with melphalan and cyclophosphamide. Melphalan was 10 times more leukemogenic than cyclophosphamide (relative risk, 31.4 vs. 3.1). There was little increase in the risk associated with total cyclophosphamide doses of less than 20,000 mg.

CONCLUSIONS

Although leukemia occurs in few patients with breast cancer, significantly elevated risks were linked to treatments with regional radiation and alkylating agents. Melphalan is a more potent leukemogen than cyclophosphamide or radiotherapy. Low risks were associated with the levels of cyclophosphamide in common use today. Systemic drug therapy combined with radiotherapy that delivers high doses to the marrow appears to enhance the risk of leukemia.

Medical management of early-stage breast cancer

With improved screening and education, a greater proportion of breast cancer is detected at an early stage. Although the prognosis for many of these patients is excellent following definitive local therapy alone, some subsets of node-negative patients have a 30% chance of eventually developing metastatic disease that will be incurable with current therapy. Thus, an increasing proportion of early-stage patients are being offered some form of adjuvant therapy, with the expectation of improved relapse-free survival, and possibly improved overall survival. Efforts have been made to base the selection of patients for adjuvant therapy on specific prognostic factors. Meanwhile, the scope and complexity of putative prognostic factors continues to widen, and now includes such items as the presence of occult microscopic metastases, DNA ploidy and proliferative fraction, cytogenetic abnormalities, oncogene expression, growth factor receptors, and expression of hormonally regulated proteins. In addition, there is now a considerable range of options with regard to the composition, dose intensity, and sequence of multimodality therapy. Data regarding the classification, significance, and interpretation of prognostic factors is reviewed together with the development, current status, and recommendations regarding adjuvant therapy for patients with early-stage breast cancer. For 1991, the National Cancer Institute (NCI) has estimated that 175,000 new cases of breast cancer will be diagnosed in American women. It is also estimated that 44,500 women will die of breast cancer. Unfortunately, the age-adjusted death rate from breast cancer has shown no overall change from 1930 through 1987. However, effective screening techniques continue to identify an increasing percentage of early-stage tumors, which should exceed 50% of all new tumors in 1991. Ultimately, our understanding of environmental and genetic risk factors may identify new ways to reduce the impact of this disease. In the interim, development and application of effective systemic adjuvant chemotherapy and hormonal therapy has become increasingly important. There is no question that a greater proportion of patients with less extensive disease are now being offered some form of adjuvant therapy. Meanwhile, selection of patients for adjuvant therapy, and choice among specific adjuvant regimens, has remained controversial. Analysis of multiple prognostic factors is performed not only in the context of cooperative investigational trials, but more often in the offices of individual physicians caring for individual patients. Tumor biopsies can now be routinely sent to specialized laboratories for performance of complex assays with potential prognostic information, although interpretation of these results with reference to a specific patient is often uncertain.(ABSTRACT TRUNCATED AT 400 WORDS)

Impact of radiation therapy and/or chemotherapy on the risk for a second malignancy after breast cancer

The risk of any second malignancy was determined for all patients treated for a primary cancer of the breast without evidence of distant metastasis at Duke University Medical Center between 1970 and 1981. The incidence, 10-year actuarial risk (AR), and relative risk (RR) of a second malignancy developing were calculated for the 407 patients who were treated with surgery alone, 226 who were treated with surgery followed by adjuvant chemotherapy (CT), 140 who were treated with surgery plus adjuvant radiation therapy (RT), and 308 who received all three modalities (CRT). The AR of a subsequent cancer (8.4% for CRT, 8.7% for CT, 8.7% for RT, and 11.7% for surgery only patients) did not differ significantly between treatment groups. The overall second cancer RR was 1.0% after CRT (95% confidence interval [CI], 0.4 to 2.0), 1.3% after RT (95% CI, 0.6 to 2.5), 1.6% after CT (95% CI, 0.9 to 2.6), and 1.7% after surgery alone (95% CI, 1.2 to 2.4). Contralateral breast cancers (RR of 4.2%; 95% CI, 2.7 to 6.3) account for the statistically significant excess of second malignancies among the surgery alone patients. The AR for contralateral breast cancer in the surgery group was higher than in either group receiving CT (P less than 0.01), but was not significantly different from the RT group. The RR for solid tumors other than breast cancer was not significantly different from unity in any of the treatment groups. The RR for acute leukemia was 16.7% in the CRT group (95% CI, 0.2 to 92.7), 11.1% in the CT group (95% CI, 0.1 to 61.8), 10.0% in the surgery alone group (95% CI, 1.1 to 36.1), and 0.0% in the RT group (95% CI, 0.0 to 61.1). This study indicated that inclusion of RT and/or CT in the initial treatment of breast cancer did not impact negatively on patients' overall risk for a subsequent malignancy during the first decade after therapy, and that adjuvant CT with or without RT may decrease their risk of a contralateral breast cancer.

Factors influencing survival and prognosis in early breast carcinoma (T1N0M0-T1N1M0). Assessment of 644 patients with median follow-up of 18 years

That there is probably a significant proportion of "cured" patients, particularly in the T1N0 group, is an important observation when one considers the proper role of adjuvant therapy, especially for patients with stage I disease. Analysis of this series indicates that patients with T1N0 disease can be subdivided into different prognostic groups. Factors associated with an especially favorable prognosis in T1N0 cases are a primary tumor size of 1 cm or less; special tumor type such as tubular, medullary, papillary, or colloid carcinoma; and low-grade tumor. Relatively unfavorable tumor characteristics are size greater than 1.0 cm (especially the group 1.7 to 2.0 cm), the presence of lymphatic tumor emboli in the breast, blood vessel invasion, high-grade tumor or poor differentiation, and intense peritumoral lymphoplasmacytic reaction. The T1N0 patients whose tumors manifest the latter features may have longer disease-free survival as a result of adjuvant therapy. On the other hand, women in the T1N0 group with an especially favorable prognosis usually can be spared adjuvant therapy.

Implication of prior treatment with drug combinations including inhibitors of topoisomerase II in therapy-related monocytic leukemia with a 9;11 translocation

The present case, together with other reports reviewed herein, defines a new subtype of therapy-related acute myeloid leukemia (t-AML). This variant of t-AML is characterized by a short interval from initial drug therapy to bone marrow dysfunction and monocytic morphology without trilineage dysplasia. Unlike classic t-AML, which frequently has abnormalities of chromosomes 5 and/or 7, this new subtype is characterized by rearrangements involving band q23 of chromosome 11, most commonly a 9;11 translocation. The majority of patients with this subtype t-AML had prior cytotoxic therapy with topoisomerase II-reactive drugs including anthracyclines, epipodophyllotoxins, or actinomycin D, combined with either an alkylating agent or cisplatin. This association of prior therapy which includes topoisomerase II-reactive agents and a rapidly appearing t-AML involving the monocytic line and chromosome 11 requires additional study.

Secondary acute myelocytic leukemia after adjuvant therapy for early-stage breast carcinoma. A new complication of cyclophosphamide, methotrexate, and 5-fluorouracil therapy

The occurrence of treatment-related hematologic malignancies after adjuvant therapy with alkylating agents for gastrointestinal cancers, ovarian carcinoma, and breast cancer and after treatment for Hodgkin's disease, non-Hodgkin's lymphoma, germ-cell tumors, and multiple myeloma has been well documented. Adjuvant chemotherapy is frequently used for the treatment of early stage breast cancer, and to date there has been no increase in the incidence of secondary myelodysplastic syndromes or acute leukemia after cyclophosphamide-based regimens when compared with surgical controls. This report describes two patients who developed acute myelocytic leukemia only after exposure to cyclophosphamide, methotrexate, and 5-fluorouracil adjuvant therapy. These two cases of acute leukemia, which developed 3 years after diagnosis of breast cancer and initiation of chemotherapy, were characterized by trilineage dysplasia and pancytopenia, and had abnormalities of chromosomes 5 and 7: characteristics consistent with treatment-related leukemia. Many women are diagnosed with early stage breast cancer each year who are potential candidates for adjuvant therapy. Although certain subgroups of patients have been shown to benefit from adjuvant therapy, continued efforts must be directed at identifying responders so that others will not be exposed to the additional risks of chemotherapy.

Adjuvant chemoimmunotherapy with LMF + BCG in node-negative and node-positive breast cancer patients: 10 year results

A total of 254 patients with stages T1-3a/N0-1/M0 operable breast cancer were randomized to either surgery alone or surgery plus adjuvant chemoimmunotherapy (LMF + BCG). Ten-year results are presented for RFS (relapse-free survival) and OAS (overall survival) in the whole patient population as well as in the most important menopausal and nodal subgroups. LMF + BCG significantly increased RFS in the whole patient population as well as in node-positive women. The earlier impressive RFS and OAS gains for node-negative patients were fading after 5 and 8 years respectively, leaving marginal trends in favour of the LMF + BCG treated women. Node-positive patients treated with LMF + BCG continue to demonstrate a marginal gain in RFS up to 10 years. This gain is nearly exclusively expressed in postmenopausal node-positive women, an observation which can be made in the node-negative patient group as well. Despite the still continuing increase in RFS,' no OAS benefit was observed for node-positive women with LMF + BCG at any time of the study. Dose still remains a critical factor in cancer therapy. However, at 10 years of follow-up, a full dose of LMF (greater than or equal to 90%) during the six cycles no longer affects OAS favourably. There was no indication of any adverse long-term toxicity of LMF + BCG in our study after a median follow-up of 10 years, especially no increase of second tumours. In the node-negative patient population, the presence or absence of intramammary lymphatic infiltration seems to be a significant prognostic factor within this nodal subgroup.