Radiation Effects on Abdominal Organs

Preoperative chemoradiation in patients with resectable rectal cancer: results on tumor response

BACKGROUND

There is no consensus about the role of preoperative radiotherapy (RT) and chemotherapy (CT) in patients with resectable cancer of the distal rectum. This study analyzed the local clinical and pathologic response in patients receiving preoperative RT/CT for rectal cancer.

METHODS

Thirty-two consecutive patients with a palpable adenocarcinoma of the rectum received preoperative RT (45 Gy in 25 fractions over 5 weeks) plus continuous chemotherapy with doxifluridine and leucovorin or 5-fluorouracil by continuous intravenous infusion during RT. Surgery was performed 8 weeks later. The Wilcoxon and chi(2) tests were used for data analysis.

RESULTS

Twelve patients had mild gastrointestinal toxicity, only one of whom required interruption of therapy. The tumor shrank to 57.8% of its original size, and at the echoendoscopy (u) there was a 58.7% decrease of the maximum diameter (P <.001). Downstaging from uT3 and uT2 to <uT3 and <uT2, respectively, occurred in 41.6% of patients (P =.0020). Total and major regression of the tumor at the histopathologic examination occurred in 12.5% and 50% of patients.

CONCLUSIONS

Local response to preoperative RT/CT was highly satisfactory and allowed conservative surgery in 81% of patients. Optimization of the combined therapy could achieve even better results.

Preoperative radiation therapy for patients with T2-T3 carcinoma of the middle-to-lower rectum

BACKGROUND

The aim of this study was to determine the effects of preoperative radiation therapy (RT) on the objective responses of patients with rectal carcinoma to their treatment. These effects were assessed with endorectal ultrasound (EUS) evaluation, histopathologic grading of postirradiation tumor mass reduction in the surgical specimen, and analysis of local and distant recurrences.

METHODS

Fifty-nine consecutive patients with palpable adenocarcinoma of the rectum, classified by EUS examination as uT2-uT3 (which meant involvement of the muscular layer and the perirectal adipose tissue, respectively), received 45 grays (Gy) over 3 weeks (2 fractions per day of 1.5 Gy each) given as photons supplied through a high-energy linear accelerator (18 MeV) through 3 fields: 1 posterior and 2 opposed lateral. Surgery was scheduled 2-3 weeks after the end of RT and included a sphincter-saving resection (39 patients) and an abdominoperineal resection (20 patients).

RESULTS

Greatest tumor dimension, which was evaluated with rectal endoscopy before RT and measurement of the lesion in the fresh specimen, showed a decrease among two-thirds of the patients; the decrease amounted to approximately one-third of the initial measurement. An echoendoscopic downstaging of the T component was observed among 24.5% of the patients. Complete tumor regression occurred in 8.5% of patients, whereas in 69% only the presence of rare residual cancer cells and prominent fibrosis were found at the pathologic examination of the specimen. Finally, the tumor regressed to pT0 and pT1 in 13.6% of the patients. The overall and disease free 2-year survival rates were 94.0% and 73.7%, respectively, for pT2 and pT3 patients, and 100% for those whose tumors regressed to pT0-pT1 after a median follow-up of 2 years.

CONCLUSIONS

Hyperfractionated preoperative RT appears to be efficient in achieving tumor shrinkage and destroying the tumor. In this study, the subset of patients with a good response to RT therapy had an excellent clinical outcome at the time of a 2-year follow-up.

[D-xylose test of resorption as a method to determine radiation side effects in the small intestine]

BACKGROUND

The D-xylose test is the most important method to determine a disorder of carbohydrates resorption in proximal small intestine. The application is based on an impaired resorption due to pathological change of small intestine surface, leading to a decreased blood level or decreased excretion in urine.

PATIENTS AND METHOD

D-xylose test was applied in 91 patients before, shortly after, 1/2 and 1 year after radiotherapy. All patients received an abdominal radiotherapy. We determined the blood level of D-xylose by a capillary blood sample 1 hour after oral D-xylose administration.

RESULTS

A significant decrease of the mean blood level of D-xylose to 1.88 mmol/l was determined after radiotherapy in comparison with 2.17 mmol/l before radiotherapy. Half a year after radiotherapy the mean blood level of D-xylose returned to normal. Regarding a threshold value of D-xylose blood level of 1.70 mmol/l 29 patients (32%) showed a pathologically decreased D-xylose resorption after radiotherapy. Twenty out of the 29 patients already showed a normal resorption half a year after the determination of the resorption disorder, 5 patients after 1 year and 4 patients after 1 1/2 years. There was no correlation between the detection of a disorder of D-xylose resorption and of a loss of body weight. The acute clinical side effects seemed to be more marked in connection with a disorder of D-xylose resorption, but this correlation is not significant. Eleven or 14 of the 29 patients, respectively, with pathologically decreased D-xylose resorption only had complaints of lower or upper gastrointestinal tract, respectively, and 10 patients did not have abdominal complaints at all.

CONCLUSIONS

The D-xylose test is an important and simple method for determination of radiogen induced carbohydrate malabsorption in proximal small intestine. By means of it radiation side effects on small intestine can also be determined in patients who are otherwise free of complaints.