The influence of local control on metastatic dissemination of prostate cancer treated by external beam megavoltage radiation therapy

Article Abstract:

Cancer treatment fails if the patient develops a local recurrence in the site of the primary cancer or develops distant metastatic cancers in other parts of the body. In principle, patients with local recurrence should be at higher risk for metastatic cancer, since the locally recurrent cancer can provide seeds for disseminated disease. However, any examination of the effect of local failure on the risk of metastasis must take other prognostic factors into account as well. The local recurrence may simply correlate with other tumor factors which also make metastatic disease more likely; in such cases the occurrence of metastatic disease would correlate with local failure, but not be a result of it. The distinction is of clinical importance, since in the latter case improvements in local control of the cancer would have little or no influence on the rate of metastatic disease and overall survival. A study was conducted to evaluate the relation between local recurrence and metastatic disease in cases of prostate cancer. A total of 602 cases of prostate cancer were treated with high-energy radiation therapy; 93 of these patients developed locally recurrent disease over follow-up periods that averaged 7.7 years. Among the patients who developed local recurrence, the rate of metastatic disease was 70 percent after 13 years. In contrast, the rate of metastasis for the patients who did not develop locally recurrent cancer was only 40 percent. As expected, many prognostic factors correlated with increased rates of metastatic disease, including more advanced cancer and higher tumor grade. However, most prognostic factors were just as likely among the patients who developed local recurrence as among those who did not, and could not account for the difference. This suggests that it is, indeed, the local recurrences themselves that contribute to the increased rate of fatal metastatic disease. Improved local control of prostate cancer, therefore, may be expected to both decrease the rate of metastatic cancer and improve patient survival. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Prostate cancer, Cancer metastasis

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Radiation apoptosis of serous acinar cells of salivary and lacrimal glands

Article Abstract:

Even low doses of radiation can result in the destruction of cells of the salivary glands and lacrimal (tear) glands. For patients undergoing radiotherapy, this destruction can be serious as well as unpleasant; without proper care, the resulting dryness of the mouth and eyes, called xerostomia and xerophthalmia, will result in the destruction of all tissues in the mouth and the outer surface of the eyes. It would be useful to observe the cells of the salivary glands and the tear glands during their death, but these tissues can not be removed from human patients for study, and can not be biopsied at the right time, since the healing processes are impaired in a patient undergoing radiotherapy. For this reason, the authors conducted a study in which experimental animals were treated with radiotherapy, and their salivary and lacrimal glands were then removed for histopathological study. In most tissues, radiation is most dangerous for cells that are reproducing. However, the cells of the salivary and lacrimal glands are not reproducing, and the microscopic examination of these cells revealed a different mechanism of cell death. The dying gland cells showed the characteristic appearance of apoptosis, also known as programmed cell death. Apoptosis occurs in the normal cycle of some lymphoid cells and during embryonic development. Cells that have outlived their normal usefulness apparently die according to some internal program, rather than as a result of some outside cause. In contrast to the radiation-induced destruction of reproducing cells, the destruction of the salivary and lacrimal gland cells appears to proceed because radiation has stimulated the expression of the cells' own internal program for death. The authors emphasize that since radiation can also affect the replication of proliferating cells, it may be possible to overlook apoptosis as an acute effect of radiation and attribute the loss of cells to the chronic effects of the loss of some reproducing cells. (Consumer Summary produced by Reliance Medical Information, Inc.)

Health aspects, Complications and side effects, Risk factors, Physiological aspects, Cell death, Eye diseases, Mouth diseases

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Conservative surgery and radiation therapy for soft tissue sarcoma of the wrist, hand, ankle, and foot

Article Abstract:

The wrist, hand, ankle, and foot pose special problems for the oncologist. When soft tissue sarcomas arise in these areas, it is often difficult for a surgeon to be satisfied that adequate margins around the cancer have been removed while still preserving function of the extremity. Although radiotherapy is often called upon in such cases to destroy traces of tumor which might be left behind, these particular regions are also traditionally considered to be especially sensitive to the damaging effects of radiation. The authors have reviewed the cases of 78 patients with soft tissue sarcoma in the wrist, hand, ankle, or foot to determine the degree to which conservative surgery and radiotherapy may be expected to provide protection from the tumor and preservation of the function of the affected structure. The disease-free survival rates were 61 and 51 percent at 5 years and 10 years, respectively. Fifteen patients (19 percent) had local recurrence of tumor, but in 12 of these cases it was possible to salvage the patient after the relapse. In 68 percent of the cases it was possible to preserve the limb in a normal or fairy normal condition; unfortunately, in 24 percent amputation was necessary. Six patients required amputation for complications, and amputation was necessary due to tumor recurrence in 13 patients. Most of the cases reviewed in this study received a radiation dose between 5,500 cGy and 6,500 cGy (a Gy, or Gary, is 1 joule of energy absorbed per kilogram of tissue). Within this narrow range, the rate of complications did not seem to be related to the radiation dose. The cases discussed here reflect the fact that conservative surgery in combination with radiation treatment is effective in the majority of patients and affords an excellent chance of preserving the affected limb. (Consumer Summary produced by Reliance Medical Information, Inc.)

Care and treatment, Sarcoma

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