Field placement errors: impact on the uncertainty in dose delivery in the external beam therapy of carcinoma of the urinary bladder

The influence of field displacement on the isodose distribution and the uncertainty in dose delivery within and outside the target volume was investigated in 10 patients receiving postoperative irradiation for bladder cancer. An overall quadratic mean displacement in the upward downward lateral anterior and posterior directions ranged from 2.6-5.4 mm and resulted in a quadratic mean uncertainty in dose delivery to the isocentre principal lymph nodes, anterior and posterior rectal walls amounting to 1.8-2.9% which corresponded to a standard deviation between 2.4-3.09% this would result in less than 5% reduction in the probability of tumour control. Tumour residues lying towards the lateral anterior or posterior parts of the target volume can be more seriously underdosed as a result of field displacements

Metastases of unknown origin

The present study included 289 patients with MUO presenting to the NCI of cairo University during 1986-1991. the age sex, site and histological characteristics were described. Treatment included different regimens of radiotherapy and or chemotherapy, chosen according to patient general condition and histological type. Prognosis of these patients were usually poor [median survival 6 months]. On the other hand patients presenting with cervical lymph node MUO usually had a relatively better outcome epecially those patients having upper and middle cervical lymph node affection who enjoyed complete remission after end of radiotherapy [median survival 3 years]. Type of malignancy did not seem to influence prognosis

Radiotherapy for nasopharyngeal carcinoma: results of treatment

A total of 123 patients suffering from nasopharyngeal carcinoma was included in the present study, 84 males and 39 females [M/F 2:1]. The age rangd between 5 - 80 y [median 50 Y]. Patients were divided into 2 groups: The first included 106 patients having localized disease and the second included 17 patients having metastatic disease. The local control rate after radical radiotherapy was 60% [group 1]. This rate increased to 80% for patients having T1, T2 and T3 tumors with either negative lymph nodes metastases less than 3 cm in diameter. On the other hand, the local control rate dropped to 16% in patients having T4 tumor or lymph node metastases more than 3 cm in diameter [P < 0.04]. The 2 - year disease free survival rate was + 26% for group [1]. This difference between the rate of local control and the disease free survival was mainly due to the occurrence of high incidence of distant metastases, especially in patients having neck node disease