Risk of acute leukemia following epirubicin-based adjuvant chemotherapy: a report from the National Cancer Institute of Canada Clinical Trials Group

Tolerability and safety of classic cyclophosphamide, methotrexate, and fluorouracil treatment in Japanese patients with early breast cancer

BACKGROUND

Few reports have addressed the feasibility and safety of classic Cyclophosphamide, Methotrexate, and Fluorouracil (CMF) therapy in Japanese female breast cancer patients.

METHODS

Twenty-four Japanese patients who received classic CMF, identical to the originally described treatment regimen were studied in terms of treatment dose, treatment delay, and toxicity.

RESULTS

Classic CMF was not discontinued in any of the cases. The median delay in treatment was 14 days, and the mean administered dose of cyclophosphamide was 98.2% of the planned dose. None of the patients suffered severe side-effects such as febrile neutropenia; however, in 22 patients in whom the effect of CMF on hair loss could be assessed, 7 (31.8%) had to wear hats or wigs.

CONCLUSIONS

Classic CMF is a feasible and safe regimen in Japanese breast cancer patients. In Japan, this regimen is still available for some specific groups of early breast cancer patients.

Anthracyclines, mitoxantrone, radiotherapy, and granulocyte colony-stimulating factor: risk factors for leukemia and myelodysplastic syndrome after breast cancer

PURPOSE

To determine the risk factors for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) after breast cancer.

PATIENTS AND METHODS

We conducted a case-control study among women treated for breast cancer between 1985 and 2001 in French general hospitals, cancer centers, or clinics. We included 182 AML and MDS patients and 534 matched controls. Breast cancer characteristics, type of treatment, and family history of cancer were compared in both groups.

RESULTS

The risk of AML/MDS was increased after topoisomerase-II inhibitor-based chemotherapy (P < 10-16) and was higher for mitoxantrone-based chemotherapy than for anthracycline-based chemotherapy (relative risk [RR] = 15.6; 95% CI, 7.1 to 34.2; and RR = 2.7; 95% CI, 1.7 to 4.5, respectively). After adjustment for other treatment components, the risk of AML/MDS in patients who received radiotherapy was multiplied by 3.9 (95% CI, 1.4 to 10.8) but was not increased by alkylating agents. Patients receiving granulocyte colony-stimulating factor (G-CSF) support had an increased risk of AML/MDS (RR = 6.3; 95% CI, 1.9 to 21), even when controlling for chemotherapy doses. Similar results were obtained when AML and MDS were considered separately.

CONCLUSION

This large case-control study demonstrates that the risk of AML/MDS is much higher with mitoxantrone-based chemotherapy than with anthracyclines-based chemotherapy in a population of women recently treated for breast cancer. The risk of AML/MDS associated with mitoxantrone must be kept in mind when using this drug to treat diseases other than breast cancer (eg, prostate cancer or multiple sclerosis). In addition, our study suggests the need to monitor the long-term effects of G-CSF therapy.

Epirubicin and cyclophosphamide, methotrexate, and fluorouracil as adjuvant therapy for early breast cancer

BACKGROUND

The National Epirubicin Adjuvant Trial (NEAT) and the BR9601 trial examined the efficacy of anthracyclines in the adjuvant treatment of early breast cancer.

METHODS

In NEAT, we compared four cycles of epirubicin followed by four cycles of cyclophosphamide, methotrexate, and fluorouracil (CMF) with six cycles of CMF alone. In the BR9601 trial, we compared four cycles of epirubicin followed by four cycles of CMF, with eight cycles of CMF alone every 3 weeks. The primary end points were relapse-free and overall survival. The secondary end points were adverse effects, dose intensity, and quality of life.

RESULTS

The two trials included 2391 women with early breast cancer; the median follow-up was 48 months. Relapse-free and overall survival rates were significantly higher in the epirubicin-CMF groups than in the CMF-alone groups (2-year relapse-free survival, 91% vs. 85%; 5-year relapse-free survival, 76% vs. 69%; 2-year overall survival, 95% vs. 92%; 5-year overall survival, 82% vs. 75%; P<0.001 by the log-rank test for all comparisons). Hazard ratios for relapse (or death without relapse) (0.69; 95% confidence interval [CI], 0.58 to 0.82; P<0.001) and death from any cause (0.67; 95% CI, 0.55 to 0.82; P<0.001) favored epirubicin plus CMF over CMF alone. Independent prognostic factors were nodal status, tumor grade, tumor size, and estrogen-receptor status (P<0.001 for all four factors) and the presence or absence of vascular or lymphatic invasion (P=0.01). These factors did not significantly interact with the effect of epirubicin plus CMF. The overall incidence of adverse effects was significantly higher with epirubicin plus CMF than with CMF alone but did not significantly affect the delivered-dose intensity or the quality of life.

CONCLUSIONS

Epirubicin plus CMF is superior to CMF alone as adjuvant treatment for early breast cancer. (ClinicalTrials.gov number, NCT00003577 [ClinicalTrials.gov].).

Topoisomerase II and the etiology of chromosomal translocations

Acute leukemias with balanced chromosomal translocations, protean morphologic and immunophenotypic presentations but generally shorter latency and absence of myelodysplasia are recognized as a complication of anti-cancer drugs that behave as topoisomerase II poisons. Translocations affecting the breakpoint cluster region of the MLL gene at chromosome band 11q23 are the most common molecular genetic aberrations in leukemias associated with the topoisomerase II poisons. These agents perturb the cleavage-religation equilibrium of topoisomerase II and increase cleavage complexes. One model suggests that this damages the DNA directly and leads to chromosomal breakage, which may result in untoward DNA recombination in the form of translocations. This review will summarize the evidence for topoisomerase II involvement in the genesis of translocations and extension of the model to acute leukemia in infants characterized by similar MLL translocations.

Body radiation exposure in breast cancer radiotherapy: Impact of breast IMRT and virtual wedge compensation techniques

PURPOSE

Recent reports demonstrate a dramatically increased rate of secondary leukemia for breast cancer patients receiving adjuvant high-dose anthracycline and radiotherapy, and that radiation is an independent factor for the development of leukemia. This study aimed to evaluate the radiation body exposure during breast radiotherapy and to characterize the factors associated with an increased exposure.

PATIENTS AND METHODS

In a prospective cohort of 120 women, radiation measurements were taken from four sites on the body at the time of adjuvant breast radiotherapy. Multiple regression analysis was performed to analyze patient and treatment factors associated with the amount of scattered radiation.

RESULTS

For standard 50 Gy breast radiotherapy, the minimal dose received by abdominal organs is on average 0.45 Gy, ranging from 0.06 to 1.55 Gy. The use of physical wedges as a compensation technique was the most significant factor associated with increased scattered dose (p < 0.001), resulting in approximately three times more exposure compared with breast intensity-modulated radiation therapy (IMRT) and dynamic wedge.

CONCLUSIONS

The amount of radiation that is scattered to a patient's body is consistent with exposure reported to be associated with excess of leukemia. In accordance with the As Low As Reasonably Achievable (ALARA) principle, we recommend using breast IMRT or virtual wedging for the radiotherapy of breast cancer receiving high-dose anthracycline chemotherapy.

Incidences and Trends of Second Cancers in Female Breast Cancer Patients: A Fixed Inception Cohort-based Analysis (United States)

OBJECTIVE

To determine incidences and time trends of second cancers among female breast cancer patients.

METHODS

Using data of the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program, we designed three inception cohorts: 1975-1977 (n=25,920), 1983-1985 (n=32,722) and 1991-1993 (n=40,819), and analyzed their incidences of second cancers during the first 8 years after initial breast cancer diagnosis.

RESULTS

Between the 1970s and the 1990s, the incidence rate of malignant second cancer significantly increased among female breast cancer patients, of which second non-Hodgkin's lymphoma and kidney cancer increased by about 150%, while second cancers of the thyroid, uterine corpus and skin melanoma increased 80%, and cancer of the lung increased 50%. The patterns of trend of second cancers were somewhat similar to those of the general population except for second endometrial cancer at all ages and second leukemia and skin melanoma among young patients aged 20-49. In the 1990s, the risk ratios (RR) of all sites cancer were found to be 5.5 (95% CI=5.0-6.1) for age 20-49, 1.3 (1.3-1.4) for age 50-64, and 1.2 (1.1-1.2) for age 65 and over, comparing breast cancer patients to general population. Additionally, radiotherapy slightly increased the risks of second leukemia (RR=1.8, 1.2-2.8), and second endometrial (RR=1.3, 1.0-1.6) and breast (RR=1.2, 1.1-1.3) cancers.

CONCLUSIONS

The fixed inception cohort method is valid for analyzing cancer registry-based second cancer data. By this method, we found that the incidence of second cancer has substantially increased among female breast cancer patients over the past 25 years. Observed changes in incidence may partially reflect the effect of treatments. Because the absolute number of affected patients is small, however, the breast cancer treatments have remained safe for most patients.

A phase III randomized trial comparing adjuvant concomitant chemoradiotherapy versus standard adjuvant chemotherapy followed by radiotherapy in operable node-positive breast cancer: final results

PURPOSE

To compare concomitant and sequential adjuvant chemoradiotherapy regimens in node-positive, operable breast cancer patients.

METHODS AND MATERIALS

This was a randomized, French, multicenter, phase III trial enrolling 638 eligible women with prior breast surgery and positive axillary dissection. Patients in Arm A received 500 mg/m2 5-fluorouracil, 12 mg/m2 mitoxantrone, and 500 mg/m2 cyclophosphamide, with concomitant radiotherapy (50 Gy +/- 10-20-Gy boost). Patients in Arm B received 500 mg/m2 5-fluorouracil, 60 mg/m2 epirubicin, and 500 mg/m2 cyclophosphamide, with subsequent radiotherapy. Chemotherapy was administered on Day 1 every 21 days for 4 cycles.

RESULTS

Median treatment durations were 64 and 126 days (Arms A and B, respectively), with no significant difference in overall or disease-free survival. Five-year locoregional relapse-free survival favored patients with conservative surgery (two thirds of the population), with less local and/or regional recurrence in Arm A than in Arm B (3% vs. 9%; p = 0.01). Multivariate analysis in this subgroup showed a 2.8-fold increased risk of locoregional recurrence with sequential chemoradiotherapy, independent of other prognostic factors (p = 0.027). Febrile neutropenia and Grade 3-4 leukopenia were significantly more frequent in Arm A. Subclinical left ventricular ejection fraction events at 1 year were more frequent with concomitant radiotherapy (p = 0.02).

CONCLUSIONS

Concomitant radiotherapy with adjuvant fluorouracil, mitoxantrone, and cyclophosphamide has significantly better locoregional control in node-positive breast cancer after conservative surgery and 50% shorter treatment, albeit with slightly more acute toxicity. With mitoxantrone no longer available for adjuvant breast cancer treatment, alternative concomitant chemoradiotherapy studies are needed.

Selection of adjuvant chemotherapy for treatment of node-positive breast cancer

Over the past two decades, several studies have suggested that regimens that contain anthracyclines are more effective than those that do not. A meta-analysis by the 2005 Early Breast Cancer Trialists' Collaborative Group confirmed that about 6 months of anthracycline-based polychemotherapy in the adjuvant setting reduced the yearly death rate from breast cancer by about 38% for women younger than 50 years and by 20% for women aged 50-69 years. Although this meta-analysis found that survival was better with regimens that contain anthracycline than with regimens based on cyclophosphamide, methotrexate, and fluorouracil, the best use of anthracycline-based regimens remains unclear. Adjuvant regimens in use can be categorised into three groups: standard-dose anthracycline; escalated-dose epirubicin; and anthracyclines and taxanes. The duration of treatment and combination of dose and drugs varies between these three categories. We reviewed the three types of regimen to establish which provide a better outcome in terms of safety, efficacy, cost, and convenience to patients. We found that both escalated-dose epirubicin and anthracycline-taxane regimens were most effective in terms of disease-free survival and overall survival. Of the specific anthracycline-based regimens, the docetaxel, doxorubicin, and cyclophosphamide regimen (TAC); the fluorouracil, 100 mg epirubicin, and cyclophosphamide regimen (FEC100); and the cyclophosphamide, epirubicin, and fluorouracil regimen (CEF) produced the greatest proportional decreases in 5-year death rate.

Risk of acute myeloid leukemia and myelodysplastic syndrome in trials of adjuvant epirubicin for early breast cancer: correlation with doses of epirubicin and cyclophosphamide

PURPOSE

We reviewed follow-up of patients treated in 19 randomized trials of adjuvant epirubicin in early breast cancer to determine incidence, risk, and risk factors for subsequent acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS).

PATIENTS AND METHODS

The patients (N = 9,796) were observed from the start of adjuvant treatment (53,080 patient-years). Cases of AML or MDS (AML/MDS) were reported, with disease characteristics. Incidence and cumulative risk were compared for possible risk factors, for assigned regimens, and for administered cumulative doses of epirubicin and cyclophosphamide.

RESULTS

In 7,110 patients treated with epirubicin-containing regimens (92% of whom also received cyclophosphamide), 8-year cumulative probability of AML/MDS was 0.55% (95% CI, 0.33% to 0.78%). The risk of developing AML/MDS increased in relation to planned epirubicin dose per cycle, planned epirubicin dose-intensity, and administered cumulative doses of epirubicin and cyclophosphamide. Patients with administered cumulative doses of both epirubicin and cyclophosphamide not exceeding those used in standard regimens (</= 720 mg/m(2) and </= 6,300 mg/m(2), respectively) had an 8-year cumulative probability of developing AML/MDS of 0.37% (95% CI, 0.13% to 0.61%) compared with 4.97% (95% CI, 2.06% to 7.87%) for patients administered higher cumulative doses of both epirubicin and cyclophosphamide.

CONCLUSION

Patients treated with standard cumulative doses of adjuvant epirubicin (</= 720 mg/m(2)) and cyclophosphamide (</= 6,300 mg/m(2)) for early breast cancer have a lower probability of secondary leukemia than patients treated with higher cumulative doses. Increased risk of secondary leukemia must be considered when assessing the potential benefit to risk ratio of higher than standard doses.

Secondary leukemia after epirubicin-based adjuvant chemotherapy in operable breast cancer patients: 16 years experience of the French Adjuvant Study Group

BACKGROUND

The purpose of this study was to evaluate incidence and risk factors of secondary leukemia after adjuvant epirubicin-based chemotherapy in breast cancer patients.

PATIENTS AND METHODS

Among eight French Adjuvant Study Group trials, 3653 patients were assessable: 2603 received epirubicin; 682 received hormonotherapy; and 368 had no systemic treatment. Chemotherapy was FEC regimen in 85% of cases (fluorouracil 500 mg/m2, epirubicin 50, 75 or 100 mg/m2, cyclophosphamide 500 mg/m2, three or six cycles). Epirubicin cumulative dose was <300 mg/m2 in 1045 patients; 300-600 mg/m2 in 1187; and > or =600 mg/m2 in 286, followed by radiotherapy in 96% of cases. The median follow-up was 104 months.

RESULTS

Eight cases of leukemia occurred in epirubicin-exposed patients and one in non-exposed patients. After 9 years, the risk of developing a leukemia was 0.34% (95% confidence interval 0.11-0.57) in epirubicin-exposed patients. In patients receiving chemotherapy, leukemia subtypes were: AML2 (two), AML3 (one), AML4 (three) and ALL (two). None of the classically recognized risk factors was significantly correlated with the occurrence of a leukemia.

CONCLUSION

Irrespective of the dose, the incidence of secondary leukemia after adjuvant epirubicin-based chemotherapy was low. After a long follow-up, the benefit/risk ratio for early breast cancer patients remained in favor of epirubicin-based adjuvant chemotherapy: eight cases (0.31%) occurred, and in some of them, treatment causality could be debatable.