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Second Primary Cancer After Radiotherapy for Prostate Cancer—A SEER Analysis of Brachytherapy Versus External Beam Radiotherapy
Page 58
M. Abdel-Wahab, I. M. Reis, and K. Hamilton
As more effective therapies for treatment of cancer have led to an increase in the number of cancer survivors, the rate of second primary cancers (SPCs) has increased, ranging as high as 16% in some cancer sites. The authors in this study specifically assessed those SPCs that may be radiation induced (RTSPC) and the effect of radiotherapy (RT)–related factors in four groups of prostate cancer patients registered in the SEER database during 1973–2002. The groups were: no RT/no surgery; external beam RT (EBRT); brachytherapy; and combined EBRT plus brachytherapy. There was a significant difference in the incidence of RTSPCs between the no surgery/no RT group and the EBRT group, with an increase of 162 cases per 100,000, or 0.16%. No significant differences were seen in RTSPCs among the radiation groups. The initial smaller relative risk of overall SPC in the implant group increased with time until the curves converged.
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Prognostic Value of Pathologic Complete Response After Neoadjuvant Therapy in Locally Advanced Rectal Cancer: Long-Term Analysis of 566 ypCR PatientsPage 99
C. Capirci, V. Valentini, L. Cionini, A. De Paoli, C. Rodel, R. Glynne-Jones, C. Coco, M. Romano, G. Mantello, S. Palazzi, F. O. Mattia, M. L. Friso, D. Genovesi, C. Vidali, M. A. Gambacorta, A. Buffoli, M. Lupattelli, M. S. Favretto, and G. La Torre
Although complete pathologic response after preoperative therapy (ypCR) has been found to constitute a favorable prognosis in patients with locally advanced rectal cancer, this has not been verified in a large series of patients. In their long-term analysis of 566 ypCR patients from 61 center who were treated with a median radiation dose of 50 Gy and followed up for a median of 46.4 months, the Gastro-Intestinal Working Group of the Italian Association of Radiation Oncology found that locoregional recurrence arose in only 7 patients (1.6%) and the 5-year cancer specific survival rate was 95% despite their locally advanced initial stage. Thus, ypCR after neoadjuvant therapy is a reliable favorable prognostic factor in patients with locally advanced rectal cancer. This evidence suggests the need for studies of less-extensive surgery in ypCR patients.
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Loss of Raf Kinase Inhibitory Protein Induces Radioresistance in Prostate CancerPage 153
K. M. Woods Ignatoski, N. K. Grewal, S. M. Markwart, A. Vellaichamy, A. M. Chinnaiyan, K. Yeung, M. E. Ray, and E. T. Keller
Although it has been shown that chemotherapeutic agents induce expression of the metastasis suppressor Raf kinase inhibitory protein (RKIP), it is not known whether radiotherapy (RT) has the same effect. Using the C4-2B prostate cancer (PCa) cell lines these authors observed that RT induced both RKIP gene expression and apoptosis in PCa cells. In cell lines engineered to prevent RT from inducing RKIP expression, apoptosis was diminished upon RT. Further, in a murine model, knockdown of RKIP diminished radiation-induced apoptosis. Thus, RT promotes apoptosis through induction of RKIP expression. This could explain the occurrence of radioresistance in some advanced cancers in which RKIP expression is often diminished.
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Risk of Developing Second Cancer From Neutron Dose in Proton Therapy as Function of Field Characteristics, Organ, and Patient AgePage 228
C. Zacharatou Jarlskog and H. Paganetti
These authors examined the risk of a second malignancy in pediatric patients with a primary cancer treated with passive scattered proton beam therapy, specifically the risk caused by neutrons outside the treatment volume. They found that the main contributors (>80%) to this risk are neutrons generated in the treatment head. Regardless, lifetime risks of a second cancer were generally <1% in association with 70-Gy treatment, with the exceptions being a higher risk of breast cancer in females and of lung cancer, leukemia, and thyroid cancer in males. The risks are influenced by field characteristics as well as patient age (due to age-dependent patient geometry and age dependencies in risk models).
