Definitive radical external beam radiotherapy for rectal cancer: evaluation of local effectiveness and risk of late small bowel damage.

AIM: To present a retrospective analysis of results of definitive radiotherapy for rectal cancer. MATERIAL AND METHODS: Forty-one consecutive patients with rectal cancer (32% primary, 61% pelvic recurrence and 7% after R2 resection) who could not be treated with surgery underwent external beam radiotherapy. A median tumour dose of 64 Gy was given with 1.8-2.5 Gy per fraction using 2D or 3D technique. In 46% of patients, concurrent 5-Fu-based chemotherapy was given. The median follow-up was 54 months. RESULTS: Clinical complete response was achieved in 39% of patients. Five-year cumulative incidence of local failure, overall survival and cancer specific survival were 76%, 26% and 30%, respectively. Of 11 patients with local control, in five cases the tumour was larger than 5 cm and in the other five the tumour was fixed. Two patients, regarded as locally controlled had non-progressive tumour without local symptoms at the last follow-up of 54 and 118 months post-radiotherapy. Late toxicity occurred in 22% of patients, all with acceptable severity. There was no bowel obstruction requiring surgery despite that in 18 patients the small bowel dose was >60 Gy to a mean volume of 51 cm(3). CONCLUSION: Definitive radio(chemo)therapy provides a chance for local control even in patients with large fixed or recurrent rectal cancer.

Enhanced level of micronuclei in peripheral blood lymphocytes of patients treated for restenosis with 32P endovascular brachytherapy.

BACKGROUND: Restenosis is the complete occlusion of the blood vessel leading to such complications as ischemia/angina, myocardial infarction, and death. It can be managed by endovascular brachytherapy with both gamma and beta sources. Endovascular brachytherapy is performed worldwide on several thousands of cases per year. The gamma-emitter 192Ir as well as the beta-emitters 32P and 90Sr are mainly used. The dose to the occluded endothelial wall is 20 Gy. Interestingly, no information with respect to the dose absorbed by the blood during the course of the treatment exists. The aim of the present investigation was to verify if the micronucleus test is suitable to detect the dose absorbed by lymphocytes in the course of endovascular brachytherapy with 32P. MATERIALS AND METHODS: Blood was drawn from 16 patients immediately before and 1 day after the treatment. Frequencies of micronuclei were assessed. In order to ensure that the micronuclei did not arise due to fluoroscopy or reperfusion, we analyzed lymphocytes of 16 control patients who underwent interventional cardiology with balloon angioplasty only. RESULTS AND CONCLUSIONS: Enhanced frequencies of micronuclei were observed in lymphocytes of some donors following brachytherapy. No correlation could be detected between the level of induced micronuclei and the absorbed dose. Also, no effect of fluoroscopy or reperfusion was seen. Thus, although brachytherapy of restenosis with 32P leads to weak enhancement of the micronucleus frequency in lymphocytes, the effect was not seen in all patients; the reason for this heterogeneous response remains to be elucidated.

Incidental irradiation of mediastinal and hilar lymph node stations during 3D-conformal radiotherapy for non-small cell lung cancer.

PURPOSE: To estimate the doses of incidental irradiation in particular lymph node stations (LNS) in different extents of elective nodal irradiation (ENI) in 3D-conformal radiotherapy (3D-CRT) for non-small cell lung cancer (NSCLC). METHODS; Doses of radiotherapy were estimated for particular LNS delineated according to the recommendations of the University of Michigan in 220 patients treated using 3D-CRT with different (extended, limited and omitted) extents of ENI. Minimum doses and volumes of LNS receiving 40 Gy or more (V40) were compared for omitted vs. limited+ extended ENI and limited vs. extended ENI. RESULTS: For omission of the ENI the minimum doses and V40 for particular LNS were significantly lower than for patients treated with ENI. For the limited ENI group, the minimum doses for LNS 5, 6 lower parts of 3A and 3P (not included in the elective area) did not differ significantly from doses given to respective LNS for extended ENI group. When the V40 values for extended and limited ENI were compared, no significant differences were seen for any LNS, except for group 1/2R, 1/2L. CONCLUSIONS: Incidental irradiation of untreated LNS seems play a part in case of limited ENI, but not in cases without ENI. For subclinical disease the delineation of uninvolved LNS 5, 6, and lower parts of 3A, 3P may be not necessary, because these stations receive the substantial part of irradiation incidentally, if LNS 4R, 4L, 7, and ipsilateral hilum are included in the elective area while this is not case for stations 1 and 2.

Delineation variation of lymph node stations for treatment planning in lung cancer radiotherapy.

PURPOSE: To assess the variability among clinicians in the delineation of mediastinal and hilar lymph node stations (LNS) according to the published recommendations in the treatment planning of elective nodal irradiation for lung cancer. METHODS: Nine observers delineated on axial CT scans of five cases the LNS according to the guidelines of the published Atlas. Next, the Volumes of Consensus (VC)--fitting strictly the guidelines--for each LNS and case were collectively defined. Volume of Intersection (VI) as the overlap of the Delineated Volume (DV) for each LNS, case and observer with respective VC was computed. The Concordance Index (CI) for respective LNS and observers was defined as "VI/VC x 100%". The Discordance Index (DI) for respective LNS and observers was defined as "(1-VI/VD) x 100%". RESULTS: Mean values of CI and DI for all observers were 69% and 36%, respectively. For five radiation oncologists who used to work as a team the ways of delineation were similar. The poorest reproducibility was shown for LNS 5, 7, 10R, and 10L. CONCLUSIONS: Although detailed guidelines are used there is still substantial room for improvement. More training in the use of the Atlas is recommended.