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Breast Cancer |
aCentre Jean Perrin and INSERM, Clermont Ferrand Cedex, France; bUniversité d'Auvergne, Faculté de Médecine, Clermont-Ferrand, France; cCentre d'Investigation Clinique, Clermont-Ferrand Cedex, France
Key Words. Breast cancer • Mitotic index • Ki-67 • Cyclin D1 • Cyclo-oxygenase-2
Correspondence: Catherine Abrial, Ph.D., Centre Jean Perrin, Bureau de Recherche Clinique, 58, rue Montalembert, BP 392, 63011 Clermont-Ferrand Cedex 1, France. Telephone: 33-4-73-27-80-05; Fax: 33-4-73-27-80-29; e-mail: Catherine.Abrial{at}cjp.fr
Received March 25, 2008; accepted for publication November 25, 2008; first published online in THE ONCOLOGIST Express on December 17, 2008.
Disclosure: The content of this article has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from commercial bias. No financial relationships relevant to the content of this article have been disclosed by the authors, planners, independent peer reviewers, or staff managers.
| ABSTRACT |
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Patients were treated using different neoadjuvant chemotherapy combinations, mainly in successive prospective phase II trials. They received a median number of six cycles (range, 1–9). After neoadjuvant chemotherapy, patients underwent surgery and radiotherapy. In cases of important residual disease, some received additional courses of chemotherapy. In addition, menopausal patients with hormone receptor–positive tumors received tamoxifen for 5 years.
According to our analysis, we found significant variations before and after neoadjuvant chemotherapy only for cyclin D1 and the mitotic index. Concerning the predictive value of biomarkers for response, Ki-67 and the mitotic index were predictive on univariate analysis, both for objective clinical and pathological complete responses. Because these two factors were correlated, no multivariate analyses were conducted. We then assessed the prognostic impact of the biopathological factors. When the factors were measured before chemotherapy, all were prognostic. When evaluated after chemotherapy, the mitotic index, objective clinical response, and pathological complete response were prognostic. Because these factors were correlated, no multivariate model was done.
The main clinical fact is that there were significant correlations between clinical and pathological responses and variations in the biological factors studied.
| INTRODUCTION |
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The current study is a continuation of others we have published [2–4]. We have assessed several factors, such as hormone receptors, human epidermal growth factor receptor (HER)-2, Scarff–Bloom–Richardson (SBR) grade and modified (M)SBR grade, and nodal involvement. In this manuscript, we focus on other markers that are characteristic of tumor proliferation and aggressiveness, that is, the mitotic index of the SBR grade, Ki-67, cyclin D1, and cyclo-oxygenase (COX)-2. First, we studied these factors before and after chemotherapy. Second, we assessed their predictive value. Third, we measured the prognostic impact of these markers and the prognostic impact of a clinical response and pathological response according to the classification systems of Chevallier et al. [5] and Sataloff et al. [6].
| PATIENTS AND METHODS |
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The baseline workup included a complete history and clinical examination, bilateral mammography, and bilateral breast ultrasound. A diagnosis of carcinoma was established through fine-needle aspiration or core needle biopsy of the primary tumor and palpable lymph nodes. When invasive adenocarcinoma was demonstrated, the tumor was evaluated for Scarff–Bloom–Richardson (SBR) grade and hormone receptors were assessed by radioimmunology or immunohistochemistry (IHC). The laboratory assessment consisted of a CBC, blood chemistry analysis, and measurement of the tumor markers (carcinoembryonic antigen and cancer antigen 15.3). The absence of distant metastasis was confirmed by chest x-ray, bone scan, and liver ultrasound.
Treatment Modalities
Between 1982 and 2004, 710 patients were treated using different protocols of neoadjuvant chemotherapy—doxorubicin, vincristine, cyclophosphamide, and fluorouracil with or without methotrexate (AVCF/M); theprubicin, vinorelbine, cyclophosphamide, and fluorouracil (TNCF); vinorelbine, epirubicin, and methotrexate (NEM); vinorelbine, epirubicin, and paclitaxel (NET); docetaxel; fluorouracil, epirubicin, and cyclophosphamide (FEC)-50, FEC-75, FEC-100, fluorouracil, doxorubicin, and cyclophosphamide 50 (FAC 50); and docetaxel–TNCF (TAXOTERE-TNCF)—mostly in successive phase II trials published separately [7–11]. Table 1 gives the precise protocols for each regimen. Patients received a median number of six cycles of neoadjuvant chemotherapy (range, 1–9). Chemotherapy was administrated i.v. at 21- or 28-day intervals. After neoadjuvant chemotherapy, patients underwent appropriate surgery according to the size of their residual tumor. Nevertheless, we have to emphasize that 27% (n = 42) of patients who received AVCF/M did not undergo surgery and directly received radiotherapy. Radiation therapy was applied after the completion of surgery or chemotherapy if adjuvant chemotherapy was given. Postoperative irradiation treatment was delivered to the chest wall, internal mammary lymph nodes, and supraclavicular/axillary lymph nodes. In cases of important residual disease, that is, at least four involved nodes and depending on the residual size of the tumor in the breast, patients could have received additional courses of chemotherapy. Finally, patients with hormone receptor–positive tumors received tamoxifen for 5 years.
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Global clinical response was estimated using the mean of the response percentage obtained by the three methods of measurement in the majority of cases. In other cases, the global clinical response corresponded to the responses obtained by the two other methods of measurement if one of them was not available.
Pathological response was independently evaluated after surgical resection of the remaining tumor and nodes. Pathologic responses were classified as follows, according to the classification systems of Chevallier et al. [5] and Sataloff et al. [6].
The Chevallier et al. Classification
The Sataloff et al. Classification
Breast
Nodes
Mitotic Counts
To obtain the mitotic count, we counted the number of mitotic figures in 10 high-power fields using a 40x objective and 10x ocular lens in areas of the tumor with the highest cellularity and number of mitotic figures. We divided the number of mitoses into three scores as used in the SBR grade [12]. All the mitotic counts were performed with the same microscope to ensure homogeneity.
IHC Studies
The Ki-67, cyclin D1, and COX-2 status were determined using IHC on 3-µm paraffin sections, conducted on whole slides before neoadjuvant chemotherapy on microbiopsies and after neoadjuvant chemotherapy on residual disease. After deparaffinization, antigen retrieval was carried out for 3 minutes in citrate buffer (pH, 7.3) in a pressure cooker for Ki-67, cyclin D1, and COX-2. Immunostaining was performed with a Nexes automated immunostainer (Ventana, Illkirch, France). The incubation time was 16 minutes and the visualization was done with the AEC detection kit (Ventana). The clones used and dilution and cutoff values for positivity are detailed in Table 2. Because many cutoff values have been assessed in the literature for biological parameters and because various results have been obtained, we have chosen to give the percentage of positive cells and then different cutoffs were applied.
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2 test was used for a descriptive analysis of the population and to assess correlations between tumor characteristics and qualitative data. The Kruskal-Wallis H-test was used to compare categorical and quantitative data. Matched-pairs tests were used to study variations in the biological markers before and after neoadjuvant chemotherapy. Response rates are presented with their 95% confidence intervals (CIs). Results were last updated in February 2008. The disease-free survival (DFS) duration was defined as the time elapsed between the date of first diagnosis and the date of first relapse, regardless of the site of relapse. The overall survival (OS) duration was the time between the date of initial diagnosis and the date of the last status report, whether the patient was alive or dead and regardless of the cause of death. Survival curves were designed using the Kaplan–Meier method [13] and were compared using the log-rank test. We used the 20-year survival rate and Rothman 95% CI to document survival. A p-value < .05 was considered significant. In the statistical hypothesis tested next, the p-value is a measure of how much evidence exists against the null hypothesis. The null hypothesis represents no change or no effect. So, the p-value is the threshold below which we consider that the observed difference in a comparison is statistically significant; that is, with a low risk for error, the null hypothesis is rejected. | RESULTS |
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Fifty-four patients were not included in the pathological assessment after chemotherapy. Most of them experienced an objective clinical response, but some did not want to undergo surgery, and after a certain period, complete responses were directly treated using radiotherapy. Of the 656 patients who underwent surgery, 94 (14.3%; 95% CI, 11.6%–17.0%) achieved a pathological complete response (pCR) in the breast and nodes according to the Chevallier et al. [5] classification, and 135 patients (25.8%; 95% CI, 22.0%–29.6%) achieved a pCR according to the Sataloff et al. [6] classification.
Surgery and Adjuvant Treatments
After neoadjuvant chemotherapy, 66% of the patients underwent conservative surgery; of the 521 patients with an axillary dissection, 265 had nodal involvement. Axillary dissection was not possible for the other patients (n = 135). In fact, 20 years ago, axillary dissections were not done systematically when patients were in complete clinical response after treatment, in order to avoid lymphedema. The median diameter of the residual tumor was 1.5 cm (range, 0–10). In all, 95% of patients received radiotherapy, 17% received adjuvant chemotherapy, and 52% received hormonal therapy with tamoxifen for 5 years.
DFS and OS
On February 29, 2008, the median follow-up period was 133 months (range, 48–312 months). The follow-up corresponds to the period between the date of diagnosis and February 29, 2008. The median follow-up was calculated from this period using software. The obtained value of 133 months means that, for 50% of the patients in this database, we have a follow-up
133 months, and for the other 50% of the patients, the follow-up is <133 months. The 20-year OS and DFS rates were 55.2% (95% CI, 51.5%–58.9%) and 48.4% (95% CI, 44.7%–52.1%), respectively. At 20 years, 236 recurrence events had been reported, with six patients remaining at risk, and 164 deaths had been reported with eight patients remaining at risk.
Immunohistological Data
Table 4 lists the tumor markers we assessed. These data were measured on biopsies before neoadjuvant chemotherapy. We also studied these parameters in the surgical resection after neoadjuvant chemotherapy. For each factor, there are missing data. Because our database is retrospective and long term, for several patients there is no longer a paraffin-embedded block on which to conduct the IHC analyses. For other patients, we did not obtain usable results because of insufficient residual tumor. Nevertheless, patients with missing marker data are not statistically different from the others, so this will not induce a bias in the analyses.
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In Table 6, we report the percentage of positive and negative values with respect to response or nonresponse to chemotherapy for each marker.
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| DISCUSSION |
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According to our results, and contrary to Penault-Llorca et al. [15], in this larger series, no significant difference in expression was observed for Ki-67 (p = .47). Moreover, no significant difference was found for COX-2 (p = .31). In the literature, we did not find any study on COX-2 variations.
Conversely, significant variations have been observed for cyclin D1 and for the mitotic index. Indeed, there was a significant increase in the percentage cells that stained positive for cyclin D1 after treatment (p = .016), and there was significantly more downgrading of the mitotic index (score 2/3 to score 1, 96 patients) than upgrading (score 1 to score 2/3, 38 patients; p = 5.4 x 10–7). No study assessing cyclin D1 variations was found in the literature. Our results concerning the mitotic index agree with the work of Amat et al. [16] on variations in the SBR grade before and after neoadjuvant chemotherapy; indeed, they reported that there were more SBR grade I tumors after chemotherapy than before.
Because our results are retrospective, it would be interesting to develop prospective studies to assess variation in these markers. It would be equally interesting to evaluate whether or not variation in these factors is prognostic.
Predictive Factors
Univariate Analysis
Mitotic Index. The mitotic index is one of the three components of the SBR grade. It is one of the older parameters studied and a more simple way to assess cellular proliferation.
Concerning its predictive value, our results show that a high mitotic index (score of 3) is predictive of an objective clinical response and pCR. These results are similar to the work of Vincent-Salomon et al. [17], who showed in a smaller series of patients that a high mitotic index is predictive of a pCR to neoadjuvant chemotherapy (50% pCR rate for high mitotic index versus 7% pCR rate for low mitotic index). Our results are also comparable with those of Amat et al. [16], who reported that SBR grade III tumors responded better to neoadjuvant treatment than SBR grade I tumors.
Ki-67. The proportion of proliferative cells can be assessed by measuring the percentage of cells with positive immunostaining for the Ki-67 antigen. This antigen is present in cells engaged in the cell cycle.
A positive Ki-67 status was associated with an objective clinical response and with a pCR, according to both the Chevallier and Sataloff classifications. These results are comparable with those obtained by Collecchi et al. [18], Chang et al. [19], Vincent-Salomon et al. [17], and Burcombe et al. [20], who concluded that proliferative activity before treatment is significantly linked to tumor response.
The results obtained for the mitotic index and for Ki-67 are very informative for physicians. Indeed, it is now recognized that a proliferative tumor responds better to neoadjuvant treatment. For example, a retrospective study published by Méklati et al. [21] on metastatic pancreatic tumors showed that the etoposide plus cisplatin combination was a very effective treatment when the tumor was proliferating. Nevertheless, it is necessary to develop prospective studies with different chemotherapies in order to know which of them is most effective in proliferating tumors.
Cyclin D1. The oncogene CCND1 is located on chromosome 11. It codes for cyclin D1, a protein implicated in cell cycle control and, in particular, the G1–S transition.
In our database, no significant correlation was found between cyclin D1 expression and response to treatment. Moreover, in the literature, we did not find any study assessing the predictive value of cyclin D1. More investigations should be performed to define more accurately the predictive role of this protein. It could, perhaps, be interesting to define a score combining the percentage of cells expressing cyclin D1 and the intensity of expression. In a prospective study, such a score could be validated.
COX-2. COX-2 is an enzyme that catalyses the transformation of arachidonic acid to prostaglandin H2. In normal tissue, COX-2 is practically not assessable, but tumor cells, and particularly breast tumor cells, are responsible for an increase in the level of this protein [22]. When tumor progression occurs, prostaglandins can induce many mechanisms, such as cellular proliferation, apoptosis, immune system modulation, and angiogenesis.
In our dataset, we did not find a significant correlation between COX-2 expression and response to treatment. In addition, just as for cyclin D1, no study has been reported in the literature. Consequently, it would be very interesting to conduct retrospective studies to build a score measuring the expression of COX-2, to validate it with retrospective trials, and then to assess the predictive impact of this biomarker.
Prognostic Factors
Univariate Analysis
The biomarkers analyzed for the prognostic study were assessed before and after neoadjuvant chemotherapy. When we considered the biomarkers before neoadjuvant chemotherapy, none were prognostic. When we considered the biomarkers after neoadjuvant chemotherapy, the mitotic index, clinical response, and pCR according to the Chevallier and Sataloff classifications were prognostic. In fact, results of our earlier work have already led us to conclude that only factors assessed after neoadjuvant chemotherapy are prognostic [2, 16].
Mitotic Index. Concerning the prognostic value of the mitotic index, according to our results, the prognosis was better for patients with low mitotic index (score 1) tumors. These results are comparable with those of Simpson et al. [23] and Laroye and Minkin [24] in the adjuvant setting. In the neoadjuvant setting, Penault-Llorca et al. [15] also concluded that the mitotic count was a prognostic factor.
Ki-67. According to our results, the expression of Ki-67 was not prognostic at a cutoff of 1%. Our conclusions were similar using a cutoff of 10% or 20%. Nevertheless, many authors have reported that Ki-67 nonexpression (cutoff <10% or 20%, according to the authors) is significantly correlated with longer OS and DFS times (with a cutoff of 10% [25] or 20% [15]). It would be very important to validate these results in prospective studies.
Cyclin D1. We did not find a significant correlation between the expression of cyclin D1 (with a cutoff of 1%) and survival, even using a cutoff of 10% or 20%. Our results are comparable with those of Michalides et al. [26], Barbareschi et al. [27], and Umekita et al. [28]. Conversely, Gillett et al. [29] concluded that overexpression of cyclin D1 is predictive of a good prognosis.
Nevertheless, we have to emphasize that these authors proposed different scores to measure cyclin D1 expression. It would be interesting to define a universal score combining the intensity of IHC and the percentage of cells expressing cyclin D1 in retrospective studies, and then validate it in prospective studies.
COX-2. According to our results, the expression of COX-2 is not prognostic with a cutoff of 1%. We obtained the same results using a cutoff of 10% or 20%. Conversely, Costa et al. [22], Denkert et al. [30], Ristimäki et al. [31], and Sivula et al. [32] concluded that overexpression of COX-2 is significantly correlated with shorter OS and DFS times. This could be explained by an increase in prostaglandin production, which could be responsible for tumor progression (cellular proliferation, immune system modulation, and angiogenesis).
As for cyclin D1, the scores proposed for COX-2 in the literature are variable, so it would be interesting to propose a universal score that combines the percentage of cells expressing COX-2 and the intensity of expression. Further prospective studies could validate this score.
As mentioned above, many cutoff values have been assessed in the literature and various results have been obtained. Thus, we chose to fix the cutoff at 1%. But, because we don't know if this value is informative, we chose to conduct other analyses using 10% or 20% as the cutoff in order to have more results to compare with those in the literature.
Response. Patients with an objective response had a significantly longer OS time than other patients. As expected from previously published studies [2, 33–38], the OS and DFS times were longer for patients with a pCR according the Chevallier or Sataloff classifications.
| CONCLUSION |
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Concerning the predictive impact of the biomarkers studied, we found that only Ki-67 and the mitotic index were predictive. Because we did not find any correlation among cyclin D1, COX-2, and response to treatment, and because we found no data in the literature, it is necessary to study these biomarkers in prospective studies.
Finally, concerning the prognostic value, as previously published, when the biomarkers were measured before neoadjuvant treatment, they were not prognostic. However, when the factors were assessed after neoadjuvant treatment, significant correlations were found: the mitotic index, objective clinical response, and pCR were prognostic.
There were correlations among the different domains of evaluation: clinical, pathological, and biological. From our results, and according to the literature, it appears that we can separate patients into two groups: (a) patients with an objective clinical response, with a decrease in the SBR grade mitotic index, with little pathological residual disease, and with less aggressive biological markers and (b) patients with stable disease or who have progressed clinically, with an increase in the SBR grade mitotic index, with a large amount of pathological residual disease, and with more aggressive biological markers.
| AUTHOR CONTRIBUTIONS |
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Provision of study materials: Xavier Durando, Marie-Ange Mouret-Reynier, Pierre Gimbergues
Collection/assembly of data: Inès Raoelfils, Florence Mishellany
Data analysis: Catherine Abrial
Manuscript writing: Catherine Abrial, Emilie Thivat, Florence Mishellany
Final approval of manuscript: Frédérique Penault-Llorca, Philippe Chollet
Other: Anne Cayre, immunohistochemistry
| ACKNOWLEDGMENT |
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| REFERENCES |
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ler BM et al. Elevated expression of cyclooxygenase-2 is a negative prognostic factor for disease free survival and overall survival in patients with breast carcinoma. Cancer 2003;97:2978–2987.[CrossRef][Medline]
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