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Computer Communication Networks↗
Biomedical subjects
M Van Lancker
Publications and source records attributed to M Van Lancker.
Prognostic factors in locoregional non-small cell lung cancer treated with radiotherapy.
By means of a retrospective study an evaluation was made of prognostic factors on survival in patients with inoperable locoregional non-small cell lung cancer. The study was performed on a group of 239 patients with a median age of 69 years, 225 men, and 14 women. Patients were treated with external radiotherapy without (184) or with (55) chemotherapy. They received either continuous-course radiotherapy (5,500 cGy in 27-28 fractions and 5.5 weeks) or split-course radiotherapy (1 series of 3,000 cGy, 2 series of respectively 3,000 cGy and 2,500 cGy, or 3 series of, respectively 3,000 cGy, 2,500 cGy, and 2,000 cGy; each series in 10 fractions and 2 weeks, separated by a 4-week interval). Univariate analysis was done by life-table analysis and log-rank test, multivariate analysis by the Cox Proportional Hazards model. The overall survival at 1, 2, and 3 years was 36%, 11%, and 4%. Survival was not significantly influenced by localization of the tumor, grading, distance to the carina, growth pattern, diameter, partial or total atelectasis, lymph node invasion or stage. No significant difference in survival was found between patients who received only radiotherapy and those treated with a combination of radiotherapy and chemotherapy. Univariate analysis showed significant better survival in patients with squamous cell epithelioma, patients without pleural effusion, patients younger than 75 years and patients receiving higher radiation doses. Multivariate analysis showed dose of radiation (P < .001) and pleural effusion (P = .03) to be independent prognostic factors.
Adult↗
Patterns of axillary lymph node metastasis in breast cancer.
The pattern of axillary lymph node involvement was analyzed in a review of 377 cases of T1-4 breast cancers. Clinical judgment of the axillary status proved to be wrong in approximately one-third of the cases. In univariate analysis, a strong correlation (P < .01) between the number of involved nodes, tumor size, and blood vessel invasion was found. Other features of the primary tumor (lymphatic invasion, degree of differentiation, presence of necrotic areas) were related to a lesser degree (P < .05). While others (age, site) were not at all significant. However, the number of nodes resected proved to be the most important determinant of all (P = .003). Also, the simple distinction between node-negative and node-positive cases is strongly dependent on the extent of axillary dissection (P = .009). In multivariate analysis, only the number of resected nodes and T stage showed a good relationship with the number of positive nodes. Skip metastases above levels 1 and 2 were seen in only 2% of the cases. A clear influence of the number of invaded nodes on survival could be demonstrated. These findings are discussed, especially as concerns the technique, prognostic significance, and therapeutic usefulness of axillary dissection.
Adult↗
Adjuvant radiation after conservative surgery for early breast cancer. Local control and cosmetic outcome.
Between 1980 and 1987, 115 patients with early breast cancer underwent conservative surgery and radiation therapy. Median follow-up from the date of surgery was 48 months. There was local recurrence in 5 of the 115 patients. Of this group, 67 patients were evaluable for cosmetic outcome. The overall cosmetic result was judged by a panel to be excellent or good in 61%, fair in 27%, and poor in 12%. Patients themselves found the cosmetic result to be excellent or good in 94%. Retraction of the inferior border of the breast, surface difference between both breasts, breast induration, scar retraction and telangiectasia correlated with the cosmetic score. Type of surgery, axillary irradiation, use of bolus, and length of follow-up all influenced the cosmetic outcome in a univariate analysis.
Breast Neoplasms↗
Routine clinical on-line portal imaging followed by immediate field adjustment using a tele-controlled patient couch.
We have evaluated the fluoroscopic on-line portal imaging (OPI) system developed by Siemens (Beamview-1, Concord, CA, U.S.A.) in routine clinical radiotherapy, involving the treatment of 883 fields (559 patient set-ups for treatment) on 21 patients. The image was typically generated by delivering 10 monitor units when used in single exposure or 1-2 monitor units on a large open field followed by 8-10 monitor units on the actual field when double exposure was used. Comparison between the portal image and the simulator film was done by eye. A region of tolerance was drawn on the simulator film and the field edges on the portal image had to project within this region. If this criterion was not met, adjustments followed by verification portal images were done before the remaining field dose was delivered. If possible, these adjustments were performed by moving the patient couch by remote control. The image quality was insufficient for evaluation in 75/883 (8.5%) fields. The abovementioned criterion was not met in 95/808 (11.8%) of the evaluable fields (26/559 patient set-ups were not evaluable). Of the 533 evaluable patient set-ups, 92 had to be adjusted (17.2%) including three (pelvic irradiations) set-ups that were adjusted on both field irradiated during the same radiotherapy session. In one case an incorrect tray (with wrong blocks) was detected and replaced. In one case (a 5.5 x 6.0 cm rectangular larynx field) the x and y axis of the field were interswitched. In one case incorrect focusing of a block was shown by the portal image. To make adjustments, the couch longitudinal position was changed 20 times (range -10 to +15 mm). The lateral position was changed 73 times (range -15 to +16 mm). The height position was changes 6 times (range -7 to +6 mm). Diaphragma rotation changes were performed 5 times (1 degree). The fraction of treatment time that was related to the use of OPI was 30.7% median (mean 32.4%, S.D. 14.1%). The range was 4.1 to 78.6%. On the basis of calculations assuming no OPI would have been used, field treatment time was increased by a median of 44.2% (mean 55.8%; S.D. 41.2%) by using OPI. The fraction of monitor units (fraction of the dose) to generate a satisfactory image was 10% median.(ABSTRACT TRUNCATED AT 400 WORDS)
Head and Neck Neoplasms↗
Prediction of severe late complications in fractionated, high dose-rate brachytherapy in gynecological applications.
The pertinence of different points and volumes, proposed for reporting and prediction of complications in classical low dose-rate brachytherapy, was tested for high dose-rate, fractionated gynecological applications. A group of patients experiencing complications (especially rectal) was compared with a group treated without complications. We found that neither single reference points nor combinations of them are good predictors of late complications (p greater than 0.5). The same applies for the dose prescribed in point A. In contrast, volume calculations proved to be highly reliable, both in single applications as well as in cumulative calculations. It is concluded that, within the given treatment schedule, volumes up to 300 cm3 (as defined by ICRU report 38) can be treated safely.
Brachytherapy↗
Radiotherapy in squamous cell esophageal cancer.
As the classical surgical treatment of squamous cell esophageal carcinoma is associated with poor 5-year survival rates and high operative mortality, radiotherapy and chemotherapy are being used as adjuvant or alternative primary treatments. The authors present their view on several therapeutic approaches and describe their irradiation technique.
Carcinoma, Squamous Cell↗