جستجوی مقالات مرتبط با کلیدواژه « سرطان ثانویه » در نشریات گروه « پزشکی »

In prostate cancer radiotherapy, due to the proximity of the prostate to the rectum, it can be affected by high radiation doses. It has been reported that about 70% of secondary cancers after prostate cancer radiotherapy occur in the bladder and rectum, which are exposed to direct radiation. Since prostate cancer radiotherapy may be accompanied by side effects, the aim of this study is to investigate the risk of secondary cancers after the radiotherapy of prostate cancer inside the outfield organs.

The dose volume histogram data relevant to 39 patients with prostate cancer (who were treated with 3-dimensional conformal radiotherapy technique in 2022 in Tehran) were extracted, and the uniform absorbed dose inside the sensitive tissues was calculated according to the gEUD concept. Then, the risks of secondary malignancies following prostate cancer radiotherapy were calculated using the model introduced by the BEIR report. Accordingly, the lifetime attributable risk values (LAR) were estimated based on the desired organs and patient age at exposure time through the calculation of Excess relative risk (ERR) and Excess absolute risk (EAR) values.

From the obtained results, the gEUD values for the rectum ranged from 51.04 Gy to 74.69 Gy and for the bladder from 27.22 Gy to 75.51 Gy. The maximum calculated risk values for the rectum and bladder were calculated to be 49.85% and 74.91%, respectively. Besides, a significant level of secondary cancer risk within the rectum and bladder was obtained for most of the studied patients. Furthermore, small values of secondary cancer risks were estimated for patients who were irradiated at older ages, and higher ones were obtained for patients who were irradiated at younger ages.

The results showed that there is a higher probability of developing secondary malignancies in the bladder than the rectum. The information obtained in this research can improve the performance of the treatment process, so that information about secondary cancers following radiation therapy for prostate cancer will ultimately help doctors design more effective and optimal treatment designs.

Prostate cancer is the most common and second leading cause of death among men in the world. Nowadays, radiotherapy has been known as one of the most affecting methods for prostate cancer treatment. Nevertheless, radiotherapy is accompanied by the concern of developing secondary cancers by the scattered radiation to the neighbor  organs at risk. Several studies have shown that secondary cancers after the radiotherapy of prostate cancer treatment, occur in tissues such as the bladder and rectum which have been exposed to direct or indirect radiations. Therefore, this review study aimed to evaluate the influencing factors for developing secondary cancers after the radiotherapy of prostate cancer. To access the previously validated published studies, Persian and English keywords such as prostate cancer, secondary cancers, radiotherapy and organs at risk have been searched in ISID, Google Scholar, Science Direct, PubMed, and World Health Organization, between 1997 and 2021. Totally 246 pieces of literature have been selected which finally, by ignoring the similar and overlapping studies, only 40 studies were reviewed. In the present study, the most affecting factors for developing secondary malignancies including the anatomical status changes, dose variations, smoking and the impact of the various treatment techniques, have been studied. The results of the reviewed studies showed a reduction of secondary cancer risks with performing the modern modalities such as proton therapy to treat prostate cancer. Moreover, organ movements and anatomical status changes which vary from one patient to others, have been reported to make a significant difference in the relative risk of secondary cancers. It has been shown that smoking may increase the risk of secondary cancers after the radiotherapy of prostate cancer, so radiotherapy and smoking may cause genetic mutations. Despite the advantages of radiotherapy for prostate cancer treatment, developing secondary cancers after the radiotherapy should not be ignored. Assessments of the affecting factors for secondary cancers after the radiotherapy of prostate cancer require social and comprehensive studies which can result in an accurate modality with fewer side effects.

Hodgkin’s disease is one of the most common childhood malignancies that with correct diagnosis and effective treatment is curable and without treatment is leading to death.The survival of patients with Hodgkin’s disease has dramatically improved over the past 30 years because of advances in treatment.However, concern for the risk of long tern complications has resulted in a number of trials to evaluate reduction of therapy. Causes of second malignancy are related to therapies (radiotherapy-chemotherapy-radiotherapy with chemotherapy), age of patients in the first treatment, sex and immunological deficits associated with Hodgkin’s disease. Two third of second malignancies are solid tumors and 1/3 are hematologic and lymphatic system cancer.In patients that treated first with radiotherapy, solid tumors appears higher and in patients treated first with chemotherapy leukemia appears higher. With this reuslts in childhood malignancies radiotherapy sholud be reduced and when patients treated with chemotherapy the cycles of treatment should be reduced too, and all patients should have follow up for second malignancy for several years. In 228 patients with Hodgkin’s disease in ten years in Hazrat Ali-Asghar Hospital, 4 second malignancies were occurred.Three cases presented with solid tumor and one case with leukemia (AML). Three cases that first treated with radiotherapy after 8, 18 and 19 years later (respectively) presented with solid tumor, one case died from brain tumor and two cases presented with thyroid cancer, had thyroidectomy and are alive. One case after 6 years of repeated chemotherapy for recurrent disease developed leukemia and finally died. Because in this center, radiotherapy is restricted, the incidence of second malignancy is less than other centers.