Present state and future prospects: a review of cooperative groups' adjuvant and neoadjuvant trials in breast cancer

RNA Interference–Mediated Depletion of Phosphoinositide 3-Kinase Activates Forkhead Box Class O Transcription Factors and Induces Cell Cycle Arrest and Apoptosis in Breast Carcinoma Cells

Breast cancer is one of the most common malignancies affecting women in the Western world and one in seven women is predicted to develop invasive breast cancer in their lifetime. Breast cancer arises following the accumulation of a series of somatic changes often including deregulation of key signal transduction pathways. The phosphoinositide 3-kinase (PI3K) pathway has been shown to be activated in breast cancer and overexpression of PI3K is sufficient to confer a malignant phenotype. Activation of the PI3K pathway serves to repress forkhead box class O (FoxO) transcription factor-mediated growth arrest and apoptosis. In this study, we used small interfering RNA (siRNA) to knockdown PI3K in three breast cancer cell lines representing different stages of cancer development. Transfection of PI3K siRNA in breast cancer cells resulted in a significant decrease in cell viability and induction of apoptosis irrespective of their estrogen receptor alpha (ERalpha) or ErbB2 status. PI3K depletion also resulted in a significant G(1) phase cell cycle arrest in ERalpha-positive breast cancer cells. Further, our data showed that PI3K knockdown resulted in a significant activation of FoxO; interestingly, a simultaneous knockdown of FoxO1a rescued the cells from apoptosis. Furthermore, the downstream effects of FoxO activation were found to be inhibition of cyclin-dependent kinase 4, cyclin-dependent kinase 6, and cyclin D1, and accumulation of p27/Kip1. Thus, we suggest that (a) PI3K plays a critical role in breast cancer development and (b) gene therapeutic approaches aimed at PI3K or the pharmacologic inhibitors of PI3K could be developed for the management of breast cancer.

Accuracy of selective sentinel lymphadenectomy after neoadjuvant chemotherapy: Effect of clinical node status at presentation

BACKGROUND

Both neoadjuvant chemotherapy and selective sentinel lymphadenectomy (SSL) are increasingly being used in treating primary breast cancer. It is important to determine whether SSL can be used after neoadjuvant chemotherapy and whether clinical node status at presentation affects accuracy of SSL.

STUDY DESIGN

Between 1995 and 2003, 53 evaluable cases of invasive breast cancer were treated with neoadjuvant chemotherapy followed by SSL and completion axillary node dissection. The accuracy of SSL and the number of failed SSLs were assessed in the entire group and in the subset that were clinically node positive at presentation.

RESULTS

The sensitivity of SSL was 96%, the negative predictive value was 96%, and the sentinel node identification rate was 94%. Of the 53 evaluable patients, 23 had clinically node-positive disease at presentation (43%) and the remainder were clinically node negative (57%). Of the successfully completed SSL, the status of the sentinel lymph node corresponded to that of overall axillary status in 49 of 50 patients (accuracy rate 98%). Two of the 23 patients with clinically node-positive disease at presentation had unsuccessful SSL. Of the remaining 21 patients with a clinically positive axilla before systemic therapy, a false-negative SSL result occurred in 1 patient (accuracy 95%, sensitivity 91%).

CONCLUSIONS

Selective sentinel lymphadenectomy after neoadjuvant chemotherapy is both feasible and accurate. Although early reports found a lower performance of SSL after neoadjuvant chemotherapy, this study suggests reevaluation of the current practice of full axillary lymph node dissection in this setting, particularly in those patients who are clinically node negative at presentation.

Early versus late hormonal therapy: debating the issues

Hormonal therapy for prostate cancer has traditionally been reserved for advanced disease, but current evidence suggests that earlier use can confer a survival advantage. Survival benefit has been observed among patients with TNM stage T3 tumors who were treated with hormonal therapy plus external irradiation. Patients with nodal metastases (D1) who received immediate treatment with hormonal therapy after radical prostatectomy and pelvic lymphadenectomy also survived longer than those who were treated only after disease progression. The patients included in these studies are distinguished from those exhibiting "biochemical" failure (ie, increased levels of prostate-specific antigen, despite local therapy). It is in these patients that the use of hormonal therapy is, at present, controversial. For the purpose of identifying the subgroup of patients who might specifically benefit from early hormonal treatment, various schemas for defining predictors of poor outcome have been developed, including nomograms and artificial neural network programs. As with hormonal therapy, the use of chemotherapy in prostate cancer has been regarded as a palliative option for hormone-refractory disease. However, positive experience with early chemotherapy in other cancers suggests that such strategies might be similarly beneficial in prostate cancer. Limited clinical data show that chemotherapy combined with hormonal therapy can increase the initial response rate and prolong survival in locally advanced disease (T3 or D2), but not in metastatic tumors. An international trial is under way to evaluate the role of adjuvant chemotherapy in patients with localized prostate cancer who are at high risk of relapse after radical prostatectomy. Thus, accumulating evidence provides a rationale for continued investigation into the use of early hormonal therapy in selected patients.