Decreasing gastrointestinal morbidity with the use of small bowel contrast during treatment planning for pelvic irradiation

Dosimetric effects of oral contrast in the planning of conventional radiotherapy and IMRT, for rectal cancer treatment

Introduction:

Contrast media are frequently used during radiation therapy simulation. However, there are concerns about dosimetric variations when dose calculation is done on contrast-enhanced computed tomography (CT). This study evaluates the dosimetric effect of oral contrast during three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc radiotherapy (VMAT) planning.

Methods:

Rectal cancer patients were consecutively enrolled. For each patient, one unenhanced CT and one contrast-enhanced CT were taken using oral and intravenous contrast. Then, a 3D-CRT plan and an Intensity-modulated radiation therapy (IMRT)/VMAT plan were generated in the enhanced CT, and the dose distribution was recalculated in the respective unenhanced CT. The beam intensities were kept the same as for the enhanced CT plans. Finally, the unenhanced and enhanced plans were compared by calculating the gamma index.

Results:

For 3D-CRT plans, there were statistically significant differences in second phase planning target volume (PTV) D2% (Mean difference (MD) between unenhanced and enhanced CT 0·01 Gy, 95% CI [0·003 to 0·02 Gy]) and in maximum doses to the bladder (MD 0·26 Gy, 95% CI [0·05 to 0·47 Gy]). For IMRT/VMAT plans, there were statistically significant differences in small intestine V45 Gy (MD 3·1 cc, 95% CI [0·81 to 5·4 cc]), bladder V45 Gy (MD 2·9%, 95% CI [1·4 to 4·3%]) and maximum dose to the bladder (MD 0·65 Gy, 95% CI [0·46 Gy to 0·85 Gy]). In addition, for PTV D98% the MD between unenhanced and enhanced CT was 0·22 Gy 95% CI [0·05 to 0·39].

Conclusions:

For most of the dose metrics, the differences were not clinically meaningful. The greatest differences were found in VMAT plans, especially in V45 Gy of the small intestine. This difference could lead to an underestimation of dose–volume metrics when the plan is based on an enhanced CT. The use of small bowel oral contrast does not significantly influence dose calculations and may not affect the acceptability of plans when adhering to constraints.

The effect of patient positioning (prone or supine) on the dose received by small bowel in pelvic radiotherapy in rectal cancer patients

PURPOSE

The small bowel is a main dose-limiting organ in pelvic radiotherapy in the patients with rectal cancer. Conventionally, pelvic radiotherapy of patients with rectal cancer is performed in the prone position.

MATERIAL AND METHODS

Thirty-nine patients underwent CT planning scan in the treatment position (20 patients in prone position group and 19 patients in supine position group). After radiation treatment planning optimization, the volumes of the irradiated small intestines were investigated.

RESULTS

The volume of irradiated small bowel was higher in the supine position (mean difference; 36,274 cm³). However, it was not statistically significant (P value=0.187) CONCLUSION: Supine position could be accepted for the patients undergoing preoperative rectal cancer chemo-radiation.

Long-term Anorectal Function after Postoperative Chemoradiotherapy in High-Risk Rectal Cancer Patients

Aims and background

After sphincter-preserving surgery for rectal cancer and postoperative radiochemotherapy, many patients have unsatisfactory anorectal functional results which are not considered by the most common toxicity scales. The aim of the present study was to retrospectively assess the long-term incidence of impaired anorectal function in rectal cancer patients who underwent anterior resection and postoperative radiochemotherapy.

Methods

Ninety-nine patients who underwent sphincter-saving surgery and postoperative radiochemotherapy for stage II-III rectal cancer from July 1991 to January 2002 were given a questionnaire on anorectal function. Postoperative incontinence was evaluated according to a scale proposed by Jorge and Wexner. Factors influencing anorectal function were examined.

Results

The median follow-up from surgery was 10 years. Ten (10.1%) patients reported ≥ 5 bowel movements per day and 26 (26.3%) experienced clustering. The median frequency of bowel movements per 24 h was 2 (range, 1–10). Stool fragmentation was recorded in 56 (56.6%) cases, and 36 (36.4%) patients experienced urgency to defecate with inability to delay defecation for more than 15 min. The mean continence score was 4.91 (median 1, range 0–18). Incontinence to flatus, liquid and solid stools was reported at least once a week in 24 (24.2%), 11 (11.1%) and 5 (5.1%) patients, respectively. According to the study criteria, 61% of patients had good functional results. None of the variables analyzed showed a significant correlation with functional outcome.

Conclusions

Although retrospective, the present study included a large selected series that had undergone uniform adjuvant treatment and was followed for a median of 10 years. Our data demonstrated that 39% of patients did not have good functional results and suffered some degree of urgency, increased frequency and occasional incontinence even many years after the surgery. Anorectal function assessment should enter routinely in clinical practice and should have importance in the therapeutic decisions.

A multi-institutional acute gastrointestinal toxicity analysis of anal cancer patients treated with concurrent intensity-modulated radiation therapy (IMRT) and chemotherapy

Using previous dosimetric analysis methods, we identified the volume of bowel receiving 30 Gy (V(30)) correlated with acute gastrointestinal (GI) toxicity in anal cancer patients treated with intensity-modulated radiation therapy and concurrent chemotherapy. For V(30)>450 cc and < or =450 cc, acute GI toxicity was 33% and 8%, respectively (p=0.003).

The effect of treatment position, prone or supine, on dose-volume histograms for pelvic radiotherapy in patients with rectal cancer

Patients undergoing radiotherapy for rectal cancer are generally treated in a prone position, with a full bladder, to reduce the volume of normal bowel in the high-dose volume. This position is difficult to maintain, and is not consistently reproducible. This study evaluates the volume of bowel and dose received in the prone and supine positions in patients undergoing pre-operative rectal cancer chemoradiation. Using CT planning, 19 consecutive patients with rectal cancer with a full bladder underwent CT scanning first in the prone position and then immediately afterwards in the supine position. The planning target volume was outlined for the prone position and transcribed to the supine scan using pre-set criteria. The bladder and small bowel were outlined in both positions. Radiotherapy was planned using three-dimensional conformal planning, and treatment was delivered using three fields with multileaf collimators in two phases: phase I, pelvis 45 Gy/25 fractions; and phase II, tumour 9 Gy/five fractions. For both positions, the volume of bowel receiving doses in 5 Gy increments from 5-45 Gy was calculated using dose-volume histograms. At 5 Gy and 10 Gy dose levels, a significantly higher volume of bowel was irradiated in the supine position (p<0.001). At 15 Gy, it was marginally significant (p = 0.018). From 20-45 Gy, there was no significant difference in the volume of bowel irradiated with each 5 Gy increment. This study demonstrates that the volume of bowel irradiated at doses associated with bowel toxicity in concurrent chemoradiation is not significantly higher in the supine position. This position could be adopted for patients undergoing pre-operative rectal cancer chemoradiation.

Sodium butyrate enemas in the treatment of acute radiation-induced proctitis in patients with prostate cancer and the impact on late proctitis. A prospective evaluation

PURPOSE

To evaluate prospectively the effect of sodium butyrate enemas on the treatment of acute and the potential influence on late radiation-induced proctitis.

PATIENTS AND METHODS

31 patients had been treated with sodium butyrate enemas for radiation-induced acute grade II proctitis which had developed after 40 Gy in median. During irradiation the toxicity was evaluated weekly by the Common Toxicity Criteria (CTC) and subsequently yearly by the RTOG (Radiation Therapy Oncology Group) and LENT-SOMA scale.

RESULTS

23 of 31 patients (74%) experienced a decrease of CTC grade within 8 days on median. A statistical significant difference between the incidence and the severity of proctitis before start of treatment with sodium butyrate enemas compared to 14 days later and compared to the end of irradiation treatment course, respectively, was found. The median follow-up was 50 months. Twenty patients were recorded as suffering from no late proctitis symptom. Eleven patients suffered from grade I and 2 of these patients from grade II toxicity, too. No correlation was seen between the efficacy of butyrate enemas on acute proctitis and prevention or development of late toxicity, respectively.

CONCLUSION

Sodium butyrate enemas are effective in the treatment of acute radiation-induced proctitis in patients with prostate cancer but have no impact on the incidence and severity of late proctitis.

A prospective study of faecal calprotectin and lactoferrin in the monitoring of acute radiation proctitis in prostate cancer treatment

OBJECTIVE

Acute radiation proctitis is a relevant complication of pelvic radiation. The purpose of this study was to investigate two markers of gut inflammation as non-invasive diagnostic tools to evaluate acute radiation proctitis.

MATERIAL AND METHODS

Twenty patients who underwent radiotherapy for prostate cancer took part in this prospective study. Radiation-induced toxicity was evaluated weekly during radiotherapy in compliance with the CTC toxicity criteria. Stool samples from patients were examined before treatment, weekly during radiotherapy and 2 weeks after the end of radiotherapy using enzyme-linked immunosorbent assay for calprotectin and lactoferrin and correlated with the CTC toxicity.

RESULTS

Calprotectin and lactoferrin faecal values increased significantly during radiation treatment and decreased about 2 weeks after cessation of radiation. Faecal concentrations of calprotectin and lactoferrin correlated with the documented radiation proctitis symptoms (all grades together) in 15/20 patients (75%). With respect to changes in faecal concentrations and correspondence to proctitis symptoms, both markers showed parallel results in 90% of the patients. On comparing calprotectin and lactoferrin concentrations between the 4th week of radiation and the 1st week, it was found that patients with any grade of toxicity exhibited a significantly higher increase in calprotectin (p = 0.044) and lactoferrin (p = 0.05), respectively, compared with those without toxicity.

CONCLUSIONS

Calprotectin and lactoferrin faecal values changed during radiation treatment and after cessation of radiation, with correlation to acute proctitis symptoms in most of the patients. Before markers are used to monitor acute radiation proctitis, further experience should be acquired. Patients will be followed to determine the predictive value of the two tested markers for chronic radiation proctitis.

Radiation Enterocolitis Requiring Surgery in Patients With Gynecological Malignancies

PURPOSE

To identify the characteristics, risk factors, and clinical outcomes of radiation enterocolitis requiring surgery in patients with gynecologic malignancies.

METHODS AND MATERIALS

The records of 1,349 patients treated with pelvic radiotherapy were retrospectively reviewed. The majority of the patients (88%) were treated with 50 Gy or 50.4 Gy pelvic irradiation in conventional fractionations with anteroposterior fields.

RESULTS

Forty-eight patients (3.6%) developed radiation enterocolitis requiring surgery. Terminal ileum was the most frequent site (50%) and most of the lesions had stenosis or perforation. On univariate analysis, previous abdominopelvic surgery, diabetes mellitus (DM), smoking and primary site had an impact on the complications, and on multivariate analysis, abdominopelvic surgery, DM, and smoking were independent predictors of the complications requiring surgery. After the surgical intervention, the frequency of Grade 2 or more bleeding was significantly lower in patients treated with intestinal resection in addition to decompression than those treated with intestinal decompression alone.

CONCLUSIONS

Severe radiation enterocolitis requiring surgery usually occurred at the terminal ileum and was strongly correlated with previous abdominopelvic surgery, DM, and smoking. Concerning the management, liberal resection of the affected bowel appears to be the preferable therapy.

Acute small bowel toxicity and preoperative chemoradiotherapy for rectal cancer: investigating dose-volume relationships and role for inverse planning

PURPOSE

The relationship between volume of irradiated small bowel (VSB) and acute toxicity in rectal cancer radiotherapy is poorly quantified, particularly in patients receiving concurrent preoperative chemoradiotherapy. Using treatment planning data, we studied a series of such patients.

METHODS AND MATERIALS

Details of 41 patients with locally advanced rectal cancer were reviewed. All received 45 Gy in 25 fractions over 5 weeks, 3-4 fields three-dimensional conformal radiotherapy with daily 5-fluorouracil and folinic acid during Weeks 1 and 5. Toxicity was assessed prospectively in a weekly clinic. Using computed tomography planning software, the VSB was determined at 5 Gy dose intervals (V5, V10, etc.). Eight patients with maximal VSB had dosimetry and radiobiological modeling outcomes compared between inverse and conformal three-dimensional planning.

RESULTS

VSB correlated strongly with diarrheal severity at every dose level (p<0.03), with strongest correlation at lowest doses. Median VSB differed significantly between patients experiencing Grade 0-1 and Grade 2-4 diarrhea (p<or=0.05). No correlation was found with anorexia, nausea, vomiting, abdominal cramps, age, body mass index, sex, tumor position, or number of fields. Analysis of 8 patients showed that inverse planning reduced median dose to small bowel by 5.1 Gy (p=0.008) and calculated late normal tissue complication probability (NTCP) by 67% (p=0.016). We constructed a model using mathematical analysis to predict for acute diarrhea occurring at V5 and V15.

CONCLUSIONS

A strong dose-volume relationship exists between VSB and acute diarrhea at all dose levels during preoperative chemoradiotherapy. Our constructed model may be useful in predicting toxicity, and this has been derived without the confounding influence of surgical excision on bowel function. Inverse planning can reduce calculated dose to small bowel and late NTCP, and its clinical role warrants further investigation.

A phase III randomized, placebo-controlled, double-blind study of misoprostol rectal suppositories to prevent acute radiation proctitis in patients with prostate cancer

PURPOSE

Acute radiation proctitis is the most relevant complication of pelvic radiation and is still mainly treated supportively. Considering the negative impact of acute proctitis symptoms on patients' daily activities and the potential relationship between the severity of acute radiation injury and late damage, misoprostol was tested in the prevention of acute radiation-induced proctitis.

METHODS AND MATERIALS

A total of 100 patients who underwent radiotherapy for prostate cancer were entered into this phase III randomized, placebo-controlled, double-blind study with misoprostol or placebo suppositories. Radiation-induced toxicity was evaluated weekly during radiotherapy using the Common Toxicity Criteria.

RESULTS

Between the placebo and the misoprostol groups, no significant differences in proctitis symptoms occurred: 76% of patients in each group had Grade 1 toxicity, and 26% in the placebo group and 36% in the misoprostol group had Grade 2 toxicity. No differences were found in onset or symptom duration. Comparing the peak incidence of patients' toxicity symptoms, significantly more patients experienced rectal bleeding in the misoprostol group (p = 0.03).

CONCLUSION

Misoprostol given as a once-daily suppository did not decrease the incidence and severity of radiation-induced acute proctitis and may increase the incidence of acute bleeding.

Comparison of the belly board device method and the distended bladder method for reducing irradiated small bowel volumes in preoperative radiotherapy of rectal cancer patients

PURPOSE

To determine the most effective method to reduce the irradiated small bowel volume when using a belly board device (BBD), a distended bladder (DB), or both in patients with rectal cancer undergoing preoperative pelvic radiotherapy (RT).

METHODS AND MATERIALS

The study involved 20 patients with rectal cancer who were scheduled to receive preoperative pelvic RT. Patients were asked to empty their bladders and then drink 300 mL of water 2 h before the treatment planning computed tomographic (CT) scan. To identify the small bowel, an oral contrast solution (450 mL) was given 1 h before the CT scan. Two sets of transverse images were taken at 1-cm-thickness intervals with patients in the prone position with or without the BBD. After voiding, two additional sets of CT scans were obtained in prone positions with or without BBD. The conventional three-field treatment plan, composed of a 6-MV photon posterior-anterior field and 15-MV photon opposed lateral fields with wedges of 45 degrees, was made using a three-dimensional treatment planning system. The beam weights of the three-field plan were equal. The volume of irradiated small bowel was calculated for doses between 10% and 100% of the prescribed dose at 10% intervals. For each 10% dose increment, the effect of the BBD and the DB on the irradiated volume was analyzed using Kruskal-Wallis, Wilcoxon signed rank, and Wilcoxon rank-sum tests.

RESULTS

All patients underwent four sets of CT scan under the conditions of four different methods as follows: Group I = empty bladder without the use of belly board; Group II = empty bladder with the use of belly board; Group III = distended bladder without the use of belly board; Group IV = distended bladder with the use of belly board. We found that the volume of irradiated small bowel decreased in the order of Group I, Group II, Group III, and Group IV at all dose levels (p < 0.05). Compared with Group I, the mean volume reduction rate (reduced volume) of irradiated small bowel in Group II varied between 14.5% and 65.4% (15.5-80.4 cm(3)), in Group III it varied between 48.1% and 82.0% (21.6-163.1 cm(3)), and in Group IV between 51.4% and 96.4% (28.6-167.1 cm(3)).

CONCLUSIONS

The DB was more effective than the BBD for reducing the volume of irradiated small bowel in rectal cancer patients receiving pelvic RT. The combination of the BBD and DB showed an additive effect and was the most effective method for reducing the irradiated small bowel volume.

Acute diarrhea during pelvic irradiation: is small-bowel volume effect different in gynecologic patients with prior abdomen operation or not?

OBJECTIVE

To evaluate volume effect of small bowel for diarrhea during pelvic irradiation in gynecologic patients with or without prior abdomen operation.

METHODS

From January 1996 through December 2003, 759 patients undergoing 4-field pelvic irradiation for cervical or uterine cancer were analyzed. Whole pelvic (WP), modified whole pelvic (MWP), or lower pelvic (LP) irradiation were delivered initially. According to contrast medium within small bowel in simulation films, we categorized the small-bowel volume of full dose related to WP fields as small-volume and large-volume groups. We recorded the severity of diarrhea until 39.6 Gy/22 fractions of pelvic irradiation. The actuarial rates of overall and moderate to severe diarrhea were compared among different groups.

RESULTS

Significantly more large-volume distribution (85%) was noted in patients >60 years without prior operation (P < 0.001). Large-volume distribution was 53%, 65%, and 82% in post-operative patients with no diarrhea, mild diarrhea, and moderate to severe diarrhea (P = 0.002), respectively. The corresponding rate was 79%, 77%, and 80% in patients without prior abdomen operation (P = 0.869). In multivariate analysis, prior operation with LP fields (P = 0.005) and prior operation with small volume (P = 0.031) were significantly protective factors for overall diarrhea. The latter was also a protective factor for moderate to severe diarrhea (P = 0.026). Prior operation could diminish overall diarrhea in patients without simultaneous large-field (WP or MWP) and large-volume. Large volume was a significant factor of overall (P = 0.014) and moderate to severe (P = 0.004) diarrhea in large-field patients with operation. The volume effect did not exist in those patients without operation.

CONCLUSION

Age and operation can change small-bowel distribution. Prior operation may attenuate diarrhea if irradiated volume of small bowel is small. There is a volume effect in post-operative rather than non-operative patients receiving large-field irradiation. More practical dose-volume evaluation of small bowel may be applied for volume effect in gynecologic patients without prior operation.

Radiation therapy of the pelvic and paraaortic lymph nodes in cervical carcinoma: a prospective three-dimensional analysis of patient positioning and treatment technique

PURPOSE

Pelvic box fields in prone position are the standard treatment for patients with cervical carcinomas. The issue investigated in this report is whether this technique should also be used when extending the planning target volume to the paraaortic region.

MATERIALS AND METHODS

In a prospective study of eight consecutive patients with cervical carcinomas, two patient positions (prone and supine) and three radiation techniques (A, anteroposterior/posteroanterior opposed fields; B, four-field box; and C, three-field technique) were examined concerning the dose to critical organs. The analysis was based on three-dimensional planning, dose-volume histograms and normal tissue complication probabilities (NTCP).

RESULTS

Compared to the prone position, the supine position led to improved organ sparing in four of seven organs (liver, both kidneys, spinal canal). In two of seven organs (rectum and bladder) no difference between prone and supine position was observed. The best sparing of small bowel was achieved in prone position. Technique B followed by technique C in the supine position resulted in the best overall sparing of critical organs concerning the volumes receiving the respective TD(5/5) doses or more. Mean NTCP values for liver, rectum and bladder were below 1.0%. The highest values of up to 12% were found for both kidneys in prone position with C and for the spinal canal with A in the prone and supine position.

CONCLUSION

According to this analysis, for the treatment of the pelvic and paraaortic lymph node regions together, supine position and technique B (alternatively C) should be preferred despite the advantages of prone position on belly boards for pelvic irradiation alone.

Factors determining acute normal tissue reactions during postoperative radiotherapy in endometrial cancer: analysis of 317 consecutive cases

BACKGROUND AND PURPOSE

Acute radiotherapy reactions are commonly underestimated and under-reported in the literature. Our aim was to evaluate the incidence and risk factors for acute reactions during postoperative radiotherapy in endometrial cancer patients.

MATERIAL AND METHODS

Performed was detailed retrospective analysis of 317 endometrial cancer patients given postoperative radiotherapy. Two hundred forty seven patients (78%) received both intracavitary (BRT) and external beam irradiation (EBRT), 49 patients (15%) received only BRT and 21 patients (7%) - only EBRT. BRT included radium (Ra) or cesium (Cs). The mean total dose at 0.5 cm for Ra and Cs was 50.5+/-10.3 Gy and 48.4+/-15.0 Gy, respectively, and the mean dose rate - 0.47+/-0.06 Gy/h and 1.42+/-0.41 Gy/h, respectively. Mean EBRT dose in the ICRU reference point was 49.0+/-3.7 Gy given in fractions of 1.54-2.49 Gy (mean 2.0+/-0.17 Gy). Radiotherapy and Oncology Group classification system was employed to score acute reactions. The impact of patient- and treatment-related factors on the risk of acute bowel and urinary bladder reactions was assessed with uni- and multivariate tests.

RESULTS

Acute radiotherapy reactions of any grade occurred in 265 patients (84%) including bowel complications in 66% and urinary bladder complications in 36%. There were 21 severe (grade 3 or 4) reactions, all but one seen in the patients treated with combined EBRT and BRT. Higher total dose (P=0.024), higher EBRT dose (P=0.022) and higher age (P=0.026) were correlated with increased acute bowel toxicity in univariate analysis. Multivariate analysis showed that higher EBRT dose (P=0.015) and older age (P=0.016) were independently correlated with the risk of acute bowel events. Higher total dose (P=0.009), BRT dose (P=0.029), BRT dose rate (P=0.004), EBRT fraction size (P=0.007), the use of Cs BRT (P=0.001) and lower parity (P=0.041) were correlated with increased risk of acute bladder toxicity in univariate test. Multivariate analysis demonstrated that the independent risk factors for acute bladder events were BRT dose rate (P=0.002) and low parity (P=0.042) and there was a trend for EBRT dose (P=0.076). In multivariate analysis there was no impact of other clinical factors (FIGO stage, diabetes mellitus, hypertension, prior abdominal surgery) on the risk of acute bowel and/or bladder reactions nor was the impact of surgery-to-radiotherapy interval, overall radiotherapy time and overall treatment time.

CONCLUSIONS

The risk of acute reactions depends both on treatment-related (BRT dose rate, EBRT dose) and patient-related factors (age, parity). Precise treatment prescription, planning and verification are of paramount concern. Further studies are warranted to evaluate the impact of extrinsic and intrinsic factors associated with acute normal tissue injury.

Adjuvant radiation therapy of patients with rectal cancer

The standard in rectal cancer has been to add adjuvant radiation therapy to surgery in patients with stage II and III disease. Total mesorectal excision has led to lower local recurrence rates, and, if properly performed, may make adjuvant radiation unnecessary for certain stage II and III patients, such as T3 N0 patients with proximal lesions. There is also debate about the best method of delivering adjuvant radiotherapy. Preoperative radiotherapy at low dose per fraction with concurrent chemotherapy offers the advantages of maximizing sphincter preservation and greater tolerability. However, this will occasionally result in treating patients who are overstaged by ultrasound and may lead to greater postoperative morbidity and mortality than postoperative radiation. Preoperative radiotherapy has stronger data to support a survival advantage when added to surgery than postoperative radiation. Two randomized, phase III European studies may answer the question of which radiation technique is best for the near future. Protracted venous infusion of 5-fluorouracil (5-FU) is the standard method of radiosensitization. However, studies are ongoing using concurrent oxaliplatin, irinotecan, and oral 5-FU prodrugs. For now, we recommend that stage II and III rectal cancer patients receive protracted venous infusion 5-FU concurrent with preoperative radiation.

The impact of patient positioning on the adequate coverage of the uterus in the primary irradiation of cervical carcinoma: a prospective analysis using magnetic resonance imaging

BACKGROUND AND PURPOSE

The intention of this prospective study is to assess the influence of different patient positionings and the use of belly boards on the coverage of the uterus by standard radiation fields.

MATERIAL AND METHODS

In 21 women with carcinoma of the uterine cervix magnetic resonance imaging (MRI) scans in prone patient position with and without belly board and computed tomography (CT) scans in supine position were analysed after superimposing standard pelvic box fields. Further, all patients underwent a second MRI field control in prone position with belly board to detect intraindividual variations in the uterus position during treatment.

RESULTS

Standard portals did not completely cover the uterus in supine position in 7/21 (33%), in prone position with belly board in 7/21 (33%) and without belly board in 5/21 (24%). Insufficient uterine coverage was found only in the anteroposterior direction. The mean distance (+/- standard deviation) between the field borders of the lateral portals and the uterus was in supine position anteriorly 3.4 cm (+/-2.2 cm) and posteriorly 1.8 cm (+/-1.3 cm), in prone position with belly board anteriorly 2.2 cm (+/-2.7 cm) and posteriorly 2.6 cm (+/-1.6 cm), prone without belly board anteriorly 3.3 cm (+/-2.4 cm) and posteriorly 1.9 cm (+/-1.1 cm). The difference was statistically significant between supine and prone position with belly board and between prone position with and without belly board. Repeated MRI controls during therapy showed no significant changes compared to the MRIs at the beginning of therapy.

CONCLUSIONS

The use of standard radiation fields results in a high percentage of geographical misfits. Three-dimensional treatment planning is a prerequisite for adequate uterus coverage.

Relationship between acute and late normal tissue injury after postoperative radiotherapy in endometrial cancer

PURPOSE

To evaluate the relationship between acute and late normal tissue reactions in 317 consecutive endometrial cancer patients treated with surgery and adjuvant radiotherapy (RT).

METHODS

The data of 317 patients (staging according to the International Federation of Gynecology and Obstetrics) treated with postoperative RT were analyzed. Both low-dose-rate brachytherapy and external beam RT were applied in 247 patients (78%); brachytherapy only in 49 (15%) and external beam irradiation only in 21 (7%). The median follow-up was 7.3 years (range 4-21). The European Organization for Research and Treatment of Cancer, Radiation Therapy Oncology Group system with elements of the late effects of normal tissue, subjective, objective, management, analytic (LENT/SOMA) scale was used to score the RT reactions. The correlation between the occurrence and severity of acute and late bowel and bladder toxicity, as well as the relationship between the severity of acute effects and time to occurrence of late reactions, were assessed using linear and logistic regression analyses.

RESULTS

Of the 317 patients, 268 (85%) experienced acute RT reactions of any grade. Severe acute bowel reactions were observed in 15 patients (5%), urinary bladder complications in 1 patient (0.5%), cutaneous in 1 patient (0.5%), and vaginal in 1 patient (0.5%). Severe acute hematologic toxicity was seen in 3 patients (1%). A total of 158 patients (51%) experienced late RT reactions of any grade. Severe late bowel reactions were observed in 19 patients (6%), urinary bladder in 5 (2%), vaginal in 3 (1%), and bone in 10 (4%). When all toxic events were considered, there was a highly significant correlation between the acute and late bowel reactions (p <0.001), but the acute and late urinary bladder reactions did not correlate (p = 0.64). The grade of acute toxicity was found to predict the grade of late toxicity for the bowel but not for the bladder (p <0.001 and p = 0.47, respectively). The severity of acute bowel and bladder toxicity did not correlate with the time to occurrence of late toxicity in these locations (p = 0.34 and p = 0.47, respectively).

CONCLUSION

Patients with increased acute bowel toxicity during postoperative RT for endometrial cancer have an increased risk of late bowel injury. A higher grade of acute bowel complications correlated with more severe late events, but was not predictive for its latency time. These findings suggest the possibility of an early indication of patients with an increased risk of late toxicity in whom preventive measures might be attempted.

The dose-volume relationship of acute small bowel toxicity from concurrent 5-FU-based chemotherapy and radiation therapy for rectal cancer

PURPOSE

A direct relationship between the volume of small bowel irradiated and the degree of acute small bowel toxicity experienced during concurrent 5-fluorouracil (5-FU)-based chemoradiotherapy for rectal carcinoma is well recognized but poorly quantified. This study uses three-dimensional treatment-planning tools to more precisely quantify this dose-volume relationship.

METHODS AND MATERIALS

Forty patients receiving concurrent 5-FU-based chemotherapy and pelvic irradiation for rectal carcinoma had treatment-planning CT scans with small bowel contrast. A median isocentric dose of 50.4 Gy was delivered using a posterior-anterior and opposed lateral field arrangement. Bowel exclusion techniques were routinely used, including prone treatment position on a vacuum bag cradle to allow anterior displacement of the abdominal contents and bladder distension. Individual loops of small bowel were contoured on each slice of the planning CT scan, and a small bowel dose-volume histogram was generated for the initial pelvis field receiving 45 Gy. The volume of small bowel receiving each dose between 5 and 40 Gy was recorded at 5-Gy intervals.

RESULTS

Ten patients (25%) experienced Common Toxicity Criteria Grade 3+ acute small bowel toxicity. A highly statistically significant association between the development of Grade 3+ acute small bowel toxicity and the volume of small bowel irradiated was found at each dose level. Specific dose-volume threshold levels were found, below which no Grade 3+ toxicity occurred and above which 50-60% of patients developed Grade 3+ toxicity. The volume of small bowel receiving at least 15 Gy (V15) was strongly associated with the degree of toxicity. Univariate analysis of patient and treatment-related factors revealed no other significant predictors of severe toxicity.

CONCLUSIONS

A strong dose-volume relationship exists for the development of Grade 3+ acute small bowel toxicity in patients receiving concurrent 5-FU-based chemoradiotherapy for rectal carcinoma.

Dislocation of small bowel volume within box pelvic treatment fields, using new "up down table" device

PURPOSE

To present the impact of a novel minimization device, the up down table (UDT), on the volume of small bowel included within a 4-field pelvic irradiation plan.

METHODS

A polystyrene bowel displacement standard mold was created and added to a customized vacuum cushion (Vac Lok) formed around the abdomen and legs of each patient in the prone position. Two hundred seventy-seven consecutive patients with pelvic malignancies treated with the UDT device were compared with 1 historic series (68 cases) treated at our division. Small bowel contrast dyes at the time of simulation were used in all patients.

RESULTS

The average volume of small bowel within the planning target volume (high-dose volume, calculated with Gallagher method) was 100 cm(3) (median 49 +/- 114) in the series treated with standard box technique and 23 cm(3) (median 0 +/- 64) in the series treated with the UDT (p < 0.001). The average volume of small bowel included in any isodose (any-dose volume) was 505 cm(3) (median 447 +/- 338) and 158 cm(3) (median 69 +/- 207), respectively (p < 0.001). The incidence of G1, G2, and G3 acute enteric toxicity (Radiation Therapy Oncology Group criteria) in the UDT series was 16%, 15%, and 1.5%; in the standard box technique, it was 28%, 25%, and 3%, respectively (p < 0.05). The incidence of acute enteric toxicity directly correlated with the irradiated small bowel volume. In the UDT series, the 5-year actuarial incidence of G3 chronic enteric toxicity was 1.8%. The setup procedures, analyzed in 18 cases, revealed no systematic errors and a standard deviation equal to +/-5 mm for random errors.

CONCLUSIONS

The UDT technique is comfortable, inexpensive, highly reproducible, and permits an almost full bowel displacement from standard radiotherapy fields.

Sulfasalazine decreases acute gastrointestinal complications due to pelvic radiotherapy

BACKGROUND

Radiation-induced gastrointestinal toxicity is a significant concern for patients who are treated with this modality for pelvic malignancies. Eicosanoids and free radicals are thought to be among the reasons for this effect. Sulfasalazine is an inhibitor of their synthesis in the mucosa. OBJECTlVE: To determine whether sulfasalazine can reduce the radiation-induced acute gastrointestinal complications.

METHODS

In this prospective, double-blind study, 31 patients receiving pelvic radiotherapy were randomized to receive two sulfasalazine 500-mg tablets twice daily or placebo, administered orally from the first day of irradiation. Patients were evaluated weekly, and gastrointestinal toxicities were graded according to the Late Effect of Normal Tissue-Subjective Objective Management Analytic (LENT-SOMA) toxicity table during pelvic radiotherapy. On the last day of week 5, the subjects were graded endoscopically, and biopsies taken from the rectum were classified histopathologically.

RESULTS

Groups did not differ in age, gender, tumor site, or irradiation procedure. During radiotherapy, grade 2 or higher gastrointestinal toxicity occurred in 20% (3/15) and 63% (10/16) of the sulfasalazine and placebo groups, respectively. This difference was significant (p = 0.017). No statistically significant differences were found in endoscopic and histopathologic evaluations.

CONCLUSIONS

Sulfasalazine is effective in decreasing clinically acute gastrointestinal toxicities. Long-term follow-up with the subjects will help to determine the net effect of sulfasalazine on the radiation-induced gastrointestinal injuries.

Adjuvant therapy for resectable rectal adenocarcinoma

The mainstay of treatment for rectal cancer over the past 100 years has been surgical resection. However, for the majority of rectal cancers treated conventionally by resection alone, locoregional recurrence is the major mode of failure. Over the past several decades, significant progress has been made in developing effective adjuvant regimens. In the United States, postoperative chemoradiation is standard treatment for T3 or node-positive patients. However, preoperative radiation with or without chemotherapy decreases local recurrence, increases sphincter preservation, and may improve survival. The purpose of this article is to review the role of adjuvant therapy in resectable rectal cancers and to update the status of ongoing randomized trials.

Influence of patient positioning on dose-volume histogram and normal tissue complication probability for small bowel and bladder in patients receiving pelvic irradiation: a prospective study using a 3D planning system and a radiobiological model

PURPOSE

A prospective study was undertaken to evaluate the influence of patient positioning (prone position using a belly board vs. supine position) on the dose-volume histograms (DVHs) of organs of risk, and to analyze its possible clinical relevance using radiobiological models.

METHODS AND MATERIALS

From November 1996 to August 1997 a computed tomography (CT) scan was done in the prone position using a belly board and in supine position in 20 consecutive patients receiving postoperative pelvic irradiation because of rectal cancer. Using a three-dimensional (3D) planning system (Helax, TMS) the DVH for small bowel, bladder, a standard planning target volume (PTV) of postoperative irradiation of rectal cancer, the intersection of volume of PTV and small bowel (PTV intersection V(SB), respectively, of PTV and bladder (PTV intersection V(B)) were defined in each axial CT slice. The normal tissue complication probability (NTCP) was determined by the radiobiological model of Lyman and Kutcher using the tolerance data of Emami. For evaluation of late toxicity alpha/beta ratio was 2.5; for evaluation of acute toxicity, it was 10. Total dose was 50.4 Gy (1.8 Gy/fraction) (ICRU 50).

RESULTS

Using the prone position compared to the supine position, the median volume of PTV intersection V(B) was reduced by 18.5 cm3 (62%). Median dose (related to the reference dose) to the bladder was 44.5% (22.4 Gy) in prone and 66.05% (33.3 Gy) in supine position (p<0.001). Median V(B) within the 90% (45.4 Gy), 80% (40.3 Gy), 60% (30.2 Gy), and 40% (20.2 Gy) isodose was significantly lower in the prone position when compared to the supine position. Using the radiobiological models, however, there was no difference of NTCP between prone position or supine position. In the prone position, median volume of PTV intersection V(SB) was reduced by 32.5 cm3 (54%). The median dose to small bowel was 30.85% (15.4 Gy) in the prone position and 47.35% (23.9Gy) in the supine position (p<0.001). Significant differences between prone and supine position were found for median V(SB) within the 90% (45.4 Gy), 80% (40.3 Gy), 60% (30.2 Gy), and 40% (20.2 Gy) isodose. According to the method of Lyman, median NTCP of small bowel was significant lower in prone than in supine position.

CONCLUSION

The prone position with a standard belly board should be the standard positioning technique for patients receiving adjuvant postoperative radiation therapy following surgery of rectal cancer. Both irradiated volume and total dose to the organs of risk can be reduced significantly. As a consequence of this, radiation induced toxicity will be minimized.

Improving the treatment of colorectal cancer: the role of EUS

The two most important factors for determining the risk of local failure and overall prognosis in colorectal carcinoma are nodal status and the depth of tumor penetration into or through the bowel wall. These features have traditionally been determined pathologically because the clinical-staging accuracy of other imaging modalities such as computed tomography (CT) has not proven sufficiently predictive of surgical staging. However, endorectal or endoscopic ultrasonography (EUS) can be used to preoperatively evaluate nodal involvement with an accuracy of up to 86% (median: 80%) and depth of tumor penetration through the bowel wall with an accuracy of up to 97% (median: 85%) for effective clinical staging. This high staging accuracy is useful in managing colorectal cancer. Through clinical evaluation of the initial stage of colorectal cancer with EUS, a patient's risk of disease recurrence can best be determined and patients stratified for the most appropriate treatment. EUS can be used to select patients with lesions that can be treated with local excision or sphincter-sparing surgery, often combined with radiation therapy, in situations otherwise requiring an abdominoperineal resection. EUS can also be used to preoperatively identify patients with locally advanced or unresectable disease. Chemoradiation can then be given preoperatively, when it appears to be better tolerated and more effective than postoperative treatment. Unresectable tumors can often be downstaged sufficiently to allow their excision. In resectable disease, EUS can also identify patients at high risk for recurrence who would benefit from adjuvant chemoirradiation. EUS for precise staging or for earlier diagnosis of recurrence will further improve the clinical outcome of patients with colorectal tumors as significant advances both in surgical techniques and in combined chemotherapy/radiotherapy continue to be made and applied selectively in a stage-dependent manner.

[Could the evaluation of the cost of complications be a worthwhile means to improve radiotherapy?]

At the present time, the current improvement of technical and dosimetric aspects of radiation oncology has to be evaluated in terms of potential benefit for the patient and the society. For this last point of view, specially designed economic analyses must be performed in order to justify the number of resources involved by these technical improvements. If the question is how the current technical procedures could reduce the risk of undesirable side-effects, the response cannot be immediately drawn from the literature. This paper emphasizes the possibility to evaluate the role of side-effects as endpoints of economic analyses when using special models in medical decision making such as Markov's. Only few oncologic situations are reliable to properly analyze the relationship between sophisticated radiation techniques and the incidence of post-radiation complications. These situations should be selected when prospective economic analyses are planned in the field of radiation therapy.

Late complications after postoperative radiotherapy in endometrial cancer: analysis of 317 consecutive cases with application of linear-quadratic model

PURPOSE

To evaluate the incidence and risk factors for late complications after postoperative radiotherapy in endometrial cancer patients.

METHODS AND MATERIAL

We performed a detailed retrospective analysis of 317 endometrial cancer patients given postoperative radiotherapy. A total of 247 patients (78%) received both intracavitary (BRT) and external beam irradiation (XRT); 49 patients (15%) received only BRT, and 21 (7%) only XRT. BRT included radium (Ra) and cesium (Cs). The mean dose rate for both isotopes at 0.5 cm from the applicator surface was 0.47 +/- 0.06 and 1.42 +/- 0.41 Gy/h, and the mean total dose was 50.5 +/- 10.3 and 48.4 +/- 15.0 Gy, respectively. Mean BRT dose at 0.5 cm was 50.1 +/- 11.7 Gy (range 14.5-71.0). Mean XRT dose in the International Commission on Radiation Units and Measurements (ICRU) reference point was 49.0 +/- 3.7 Gy (range 22.0-66.0) given in fractions of 1.54-2.49 Gy (mean 2.0 +/- 0.17) with a two- or four-field technique. Follow-up ranged from 4 to 21 years (median 7.3). Normalized total dose (NTD) including XRT and BRT doses was calculated based on a linear quadratic equation.

RESULTS

Five-year overall survival rate was 75%, and 5-year disease-free survival (censored for noncancer deaths) was 81%. Late radiotherapy complications of any grade occurred in 158 patients (51%), including bowel complications in 41% and urinary bladder complications in 21%. A total of 37 grade 3 or 4 complications were observed in 33 patients (11%), of whom 32 were treated with both XRT and BRT. Severe bowel and/or urinary bladder complications occurred in 24 patients: in 14 of 72 patients (19.4%) who received XRT and Cs BRT, and in 10 of 172 patients (6.0%) applied XRT and Ra BRT. The higher proportion of severe bowel and/or bladder complications in the former group was due to the particularly frequent rate of these events (30.0%) in a subset of 47 patients who received XRT combined with Cs BRT at the dose rate of 1.7 Gy/h and the total BRT dose of 60 Gy. Higher NTD, XRT fraction dose, BRT dose rate, Cs BRT, two-field XRT technique, short overall radiotherapy time, and older age were correlated with increased late-event risk in univariate analysis. Multivariate Cox analysis demonstrated that the independent risk factors for late bowel complications were NTD (p = 0.000) and BRT dose rate (p = 0.036), whereas for bladder complications they were BRT dose rate (p = 0.005) and XRT fraction dose (p = 0.041). Neither clinical factor (age, parity, prior abdominal surgery, FIGO stage, diabetes mellitus, or hypertension) nor the surgery-to-radiotherapy interval, nor overall radiotherapy time was independently associated with the risk of late bladder or bowel complications.

CONCLUSIONS

The risk of late complications after postoperative radiotherapy in endometrial cancer depends mainly on treatment-related factors: NTD, BRT dose rate, and XRT fraction dose. The use of combined XRT and BRT increases the risk of late effects. NTD calculations including BRT dose rate and XRT fraction dose enable estimation of radiobiologically equivalent dose and can decrease the risk of mistakes when the radiotherapy regimen is changed.

Efficacy of a belly board device with CT-simulation in reducing small bowel volume within pelvic irradiation fields

PURPOSE/OBJECTIVE

Acute and chronic small bowel toxicity associated with pelvic irradiation limits dose escalation for both chemotherapy and radiotherapy for rectal cancer. Various surgical and technical maneuvers including compression and belly board devices (BBD) have been used to reduce small bowel volume in treatment fields. However, quantitative dose volume advantages of such methods have not been reported. In this study, the efficacy of BBD with CT-simulation is presented with dose-volume histogram (DVH) analyses for rectal cancer.

METHODS AND MATERIALS

Twelve consecutive patients referred to our department with rectal cancer were included in this study. Patients were given oral contrast 1.5 h prior to scanning and instructed not to empty their bladder during the procedure. The initial CT scan without BBD was taken in the prone position with an immobilization cast. A second CT study was performed with a commercially available BBD consisting of an 18-cm thick hard sponge with an adjustable opening (maximum 42 x 42 cm2). All patients were positioned prone over the BBD so that the opening was above the treatment volume and usually extended from the diaphragm to the bottom of the fourth lumbar spine. Image fusion between both sets of CT scans (with and without BBD) was performed using common bony landmarks to maintain the same target volume. The critical structures including small bowel and bladder were delineated on each slice for DVH analysis. On each study, a three-field optimized plan with conformal blocks in beams-eye-view was generated for volumetric analysis. The DVHs with and without BBD were evaluated for each patient.

RESULTS

The median age and body weight of 12 patients (4 females and 8 males) were 57.5 years and 82.7 kg, respectively. The changes in posterior-anterior (PA) and lateral separation with and without BBD at central axis slices were analyzed. The changes in lateral separation were minimal (<0.8 cm); however, the PA separation was reduced by 11.3 +/- 3.3% when BBD was used. The reduction in PA separation was directly related to the reduction in small bowel volume. The small bowel volume was significantly reduced with a median reduction of 70% (range 10-100%) compared to the small bowel volume without BBD. The small bowel volume reduction did not correlate either with body weight, age, gender, or sequence of radiation treatment with surgery (pre-op vs. post-op). The DVH analysis of small bowel with BBD showed significant volume reduction at each dose level. For 50% patients, the DVH analysis demonstrated an increase in bladder volume with BBD. All patients treated with the BBD completed their treatment without any break and without significant acute gastrointestinal or genitourinary toxicity.

CONCLUSIONS

For rectal cancers, small bowel is the dose-limiting structure for acute and chronic toxicity. The use of the BBD should improve the tolerance of aggressive combined modality treatment by reducing the small bowel volume within the pelvis compared to the prone position alone. The BBD provides an easy, economical, comfortable, and noninvasive technique to displace small bowel from pelvic treatment fields. The small bowel volume is dramatically reduced at each dose level. The volume reduction does not correlate with gender, age, weight, pelvic separation, and sequence of radiation treatment vs. surgery.

[The acute toxicity of the simultaneous radiochemotherapy of rectal carcinoma]

AIM

We retrospectively examined the acute toxicity of (neo-)adjuvant combined treatment for rectal cancer in an attempt to evaluate potential factors that influence the severity of toxic side effects.

PATIENTS AND METHOD

Between 1987 and 1995, 120 patients with rectal cancer (73 patients with primary tumor, 47 with recurrent disease) received chemoradiation for rectal cancer. Fifty-six patients received preoperative chemoradiation, 64 patients were treated postoperatively. Radiation was given by 4-field box technique with 6 to 10 MV-photons. Daily fraction size was 1.8 Gy, total dose 50.4 Gy (range: 41.4 to 56 Gy) +/- 5.4 Gy (range: 3.6 to 19.8 Gy) local boost in selected cases, specified to the ICRU reference point. During the first and fifth week of radiation 5-FU at a dose of 1000 m2/d for 120 hours was administered by continuous infusion. Toxicity was recorded following (modified) WHO-criteria.

RESULTS

Acute grade 3 toxicity occurred mainly as diarrhea (33%), perineal skin reaction (37%), and leukopenia (10%). Extension of the treatment volume including paraaortic lymph nodes (L3) led to a significant increase of grade 3-diarrhea (68% vs. 25%, p = 0.0003) and grade 3-leukopenia (18% vs. 8%, p = 0.03). After abdominoperineal resection less patients suffered from grade 3-diarrhea (8% vs. 47% after sphincter preserving procedures, p = 0.0006), whereas severe perineal erythema occurred more frequently (56% vs. 29%, p = 0.02). Women had significantly more toxic side effects (grade 3-diarrhea: 39% vs. 16% in men, p = 0.04; grade 2 to 3-nausea/emesis: 21% vs. 8% in men, p = 0.018; grade 2 to 3-leukopenia 53% vs. 31% in men, p = 0.02). After preoperative chemoradiation a significant reduction of grade 3-diarrhea (11% vs 29%, p = 0.03) and grade 3-erythema (16% vs. 41%, p = 0.04) was noted.

CONCLUSION

Treatment volume, type of surgery, sex and sequence of treatment modalities are the most important factors that influence the severity of toxic side effects. Individual adjustment of 5-FU dosage by monitoring its systemic clearance (which is lower in women) could help to avoid toxic side effects. The reduced acute toxicity of the preoperative approach provides a further argument in favor of the neoadjuvant chemoradiation for rectal cancer.

A randomized double blind placebo controlled multicenter study of mesalazine for the prevention of acute radiation enteritis

BACKGROUND AND PURPOSE

Symptoms of acute radiation enteritis (ARE), dominated by diarrhea, occur in more than 70% of patients receiving pelvic irradiation. Eicosanoids and free radicals release have been implicated in the pathogenesis. Mesalazine (5-ASA) is a potent inhibitor of their synthesis in the mucosa and could therefore be of some interest in preventing ARE.

PATIENTS AND METHODS

The study was performed in six radiotherapy units in France who agreed on standardized irradiation procedures. One hundred and fifty-three patients planned for external beam radiotherapy to the pelvis > or = 45 Gy for prostate (n = 97) or uterus (n = 54) cancer were randomized on a double blind basis to receive prophylactic 5-ASA (4 g/day Pentasa) or placebo. Patients with concomitant chemotherapy were excluded. Prostate and uterus cancers were chosen since these centropelvic tumors require a similar radiotherapy protocol during the first step of treatment and involve a comparable volume of small intestine. The symptoms of ARE and their severity were assessed every week during irradiation, and 1 and 3 months after its end. All patients followed a low fiber and low lactose diet. End points were diarrhea, use of antidiarrheal agents, abdominal pain, and body weight. Effficacy was evaluated using intention to treat.

RESULTS

(means +/- SD) Groups did not differ for age (mean 64 +/- 9 years), sex, tumor site, or irradiation procedure. During irradiation, diarrhea occurred in 69% and 66% of the 5-ASA and placebo groups, respectively (chi2, P = 0.22). Curves of survival without diarrhea did not differ between groups (logrank P = 0.09). Severity of diarrhea did not differ between groups except at d15 where it was significantly more severe in the 5-ASA group (ANOVA P = 0.006). Duration of diarrhea did not differ (22 +/- 15 days in both groups, P = 0.88). Abdominal pain was less frequently reported in the 5-ASA group at d28 (34% vs. 51%, P = 0.048). Use of antidiarrheal agents and body weight did not differ between groups.

CONCLUSION

Mesalazine 4 g/day did not decrease the symptoms of ARE.

Endometrial cancer

Carcinoma of the uterine corpus (endometrial cancer) remains the gynecologic malignant disease with the highest annual prevalence in the United States. The most common histologic type is adenocarcinoma, although more aggressive variants (e.g., papillary serous carcinoma and clear cell carcinoma) have been identified. Risk factors that are strongly associated with the development of endometrial cancer include tamoxifen therapy, obesity, and stimulation from unopposed estrogen (from exogenous sources or endogenously secreting ovarian tumors). The current staging system of the International Federation of Gynecology and Obstetrics is based on surgical-pathologic findings. Survival has been directly correlated with tumor stage in this staging system. The cornerstone of therapy is total abdominal hysterectomy with bilateral salpingo-oophorectomy. Pelvic and para-aortic lymphadenectomy may provide additional prognostic information but probably does not confer a therapeutic advantage. Moreover, such nodal dissections predispose to the development of complications, especially in women who subsequently receive pelvic irradiation. Other than surgical treatment, irradiation is the single most active therapy for endometrial carcinoma. In fact, some women who are not candidates for hysterectomy because of medical contra-indications can be cured with radiation alone. Adjuvant therapy following hysterectomy is based on patient- and tumor-related features that provided prognostic information for incidence and pattern of recurrence. Adjuvant treatment usually includes pelvic irradiation for selected patients. Current investigational strategies are directed at the role of whole-abdomen irradiation, extended-field irradiation, and systemic chemotherapy. The most active systemic agents include cisplatin, doxorubicin, paclitaxel, and progestins.

The lack of impact of pelvic irradiation on small bowel mobility: implications for radiotherapy treatment planning

PURPOSE

Small bowel contrast is frequently used during simulation for patients undergoing pelvic radiotherapy to assist in the design of blocks that exclude small bowel from the radiation field. In many instances, a large field is treated to 45 gray (Gy), followed by a field reduction to exclude the small bowel. This prospective study was designed to assess whether the position and mobility of the small bowel changed after the initial 45 Gy, thereby determining whether a special small bowel series done at initial simulation is applicable at the time of field reduction.

METHODS AND MATERIALS

Twelve patients undergoing pelvic irradiation were given small bowel contrast for their initial simulation. Radiographs were taken with the bladder empty and the bladder full. The location of the small bowel and its displacement with bladder distention was measured. This entire procedure was repeated prior to field reduction (after 39.6-46.0 Gy).

RESULTS

There was no demonstrable alteration in small bowel mobility after 39.6-46.0 Gy. The approximate position of the small bowel relative to bony landmarks was unchanged.

CONCLUSION

The position and mobility of the small bowel appears not to be affected by 39.6-46.0 Gy of pelvic radiotherapy. Therefore, it is reasonable to design reduced pelvic fields to exclude the small bowel based on special small bowel series done at initial treatment simulation.

Intestinal complications of radiotherapy in gynecologic malignancy--clinical presentation and management

Radiation therapy is an effective treatment modality for various gynecologic malignancies. In spite of advances in radiotherapy equipment and techniques over the years, the gastrointestinal and urinary tracts have remained a considerable problem with radiotherapy of the pelvis and abdomen. Clinical presentation of intestinal complications, current concepts of pathophysiology and principles of medical and surgical management are reviewed.

A practical technique for conformal simulation in radiation therapy of pelvic tumors

PURPOSE

A radiological procedure, based on straightforward conventional methods, was used for a demonstration of pelvic anatomy during simulation to precisely delineate the target volume and increase the probabilities of pelvic tumor control.

METHODS AND MATERIALS

Between 1990 and 1993, 450 patients with primary pelvic malignancies underwent external radiotherapy by means of photons, 6-10 MeV, with multiple-field techniques. The simulation was carried out immediately following a pelvic organs opacification (POO) by standard methods. This procedure used a minimal quantity of contrast media (barium sulphate, iodine contrast) and metallic markers to locate directly and simultaneously: (a) small intestine, (b) bladder, (c) rectum, (d) anal canal, (e) bulbous male urethra, and (f) vagina. When all these structures were clearly visualized, the procedure was scored as successfully performed.

RESULTS

The sensitivity of procedure was defined as the percentage of successful pelvic organs opacification (POO) carried out in the patients. It was 98% in both women and men. Indirectly, the procedure helped us to locate the prostate, the perineum, and the uterus cervix in the same percentage of patients. Pelvic organs opacification allowed us to document not only the normal position of the pelvic organs tested, but also any variations (ranging from 5% to 40% of cases, after pelvic surgery). Furthermore, POO revealed previously not-reported abnormalities in patients undergoing surgery, mostly rectal stenosis, urinary or anal incontinence, and bladder luxation. The cost of the materials used was $10-15 for each POO, and the time required 5-7 min. The side effects were 7% and not significant.

CONCLUSION

In the simulation phase for multiple-field irradiation technique, the simultaneous visualization of pelvic organs obtained by POO procedure allows an exact positioning of the isocenter, an accurate shielding of structures, and finally, a reliable conformal therapy. Due to the low cost, the short length, and the insignificant side effects, POO can be carried out more than once during pelvic treatments for localization and verification of target.

Late effects of radiation therapy on the gastrointestinal tract

Late gastrointestinal complications of radiation therapy have been recognized but not extensively studied. In this paper, the late effects of radiation on three gastrointestinal sites, the esophagus, the stomach, and the bowel, are described. Esophageal dysmotility and benign stricture following esophageal irradiation are predominantly a result of damage to the esophageal wall, although mucosal ulcerations also may persist following high-dose radiation. The major late morbidity following gastric irradiation is gastric ulceration caused by mucosal destruction. Late radiation injury to the bowel, which may result in bleeding, frequency, fistula formation, and, particularly in small bowel, obstruction, is caused by damage to the entire thickness of the bowel wall, and predisposing factors have been identified. For each site a description of the pathogenesis, clinical findings, and present management is offered. Simple and reproducible endpoint scales for late toxicity measurement were developed and are presented for each of the three gastrointestinal organs. Factors important in analyzing late complications and future considerations in evaluation and management of radiation-related gastrointestinal injury are discussed.

Perioperative radiotherapy +/- chemotherapy in rectal cancer

Locoregional failure which occurs in 25%-50% of patients with rectal cancer undergoing potentially curative surgery, can be significantly reduced by either postoperative adjuvant irradiation and also by preoperative radiotherapy. In view of the possible local side effects/complications, optimal irradiation techniques including accelerator and 3-4 field techniques are mandatory. Combined treatment consisting of radiotherapy plus chemotherapy appears to be more efficient than pelvic irradiation alone. It seems that reductions in the rate of pelvic and extrapelvic tumor recurrences which are not dramatic but of clinical significance are followed by an improved survival. The 1990 Consensus conference of the National Institute of Health recommended combined postoperative radiotherapy and chemotherapy for patients with T3N0, T4N0 and any TN1-3 rectal cancer. For future trials, the main goal has to be optimization of radiotherapy plus chemotherapy in the perioperative treatment of rectal cancer. The most important unanswered question is whether the highest therapeutic ratio is obtained by pre- or postoperative treatment.

Adjuvant postoperative accelerated hyperfractionated radiotherapy in rectal cancer: a feasibility study

PURPOSE

To assess the acute toxicity and hence feasibility of postoperative hyperfractionated accelerated radiotherapy in rectal cancer.

METHODS AND MATERIALS

Twenty patients were submitted to accelerated hyperfractionated radiotherapy after resection of rectal cancer. A total dose of 48 Gy was given in 3 weeks. Two fractions of 1.6 Gy were used with a mean interfraction interval of at least 6 hours. The pelvic volume was treated by a four-field box technique using a linear accelerator (6-18 MV). Acute toxicity was assessed once per week. Small bowel and skin toxicity were scored according to the criteria of the World Health Organization. Bladder toxicity was scored according to the criteria of the Radiation Therapy Oncology Group.

RESULTS

All the patients underwent the treatment as planned except one. No patient presented grade 3 or 4 bladder toxicity. There was only one patient who complained from grade 3 skin toxicity at the end of the treatment. Fourteen patients had some degree of intestinal toxicity. This was the most frequently occurring acute side-effect. Only two out of the fourteen patients had intestinal toxicity exceeding grade 2.

CONCLUSION

Hyperfractionated accelerated radiotherapy on a pelvic volume is feasible as far as acute toxicity is concerned.

Volumetric analysis of small bowel displacement from radiation portals with the use of a pelvic tissue expander

PURPOSE

Many techniques and devices have been used in an attempt to minimize gastrointestinal morbidity of pelvic irradiation. The value of a temporary intrapelvic tissue expander to displace small bowel from pelvic radiotherapy fields was analyzed by comparing volumetric treatment parameters of patients with and without such a device.

METHODS AND MATERIALS

Between 1983 and 1991, 77 patients with a diagnosis of endometrial (n = 35), colorectal (n = 41), or anal carcinoma (n = 1) received adjuvant postoperative radiotherapy after undergoing treatment planning simulation with the use of small bowel oral contrast medium. Fourteen of these patients underwent surgical placement of a temporary intrapelvic tissue expander prior to radiotherapy, and 63 patients did not. Small bowel volume within the treatment portals was measured for both initial pelvic and conedown fields for all cases, and compared between the two patient groups.

RESULTS

The volume of small bowel within the initial pelvic fields receiving full dose irradiation was significantly less among patients with a tissue expander. For patients with a tissue expander, mean volume receiving full dose irradiation was 25 cm3 (median 0 cm3, range 0-297 cm3), whereas the corresponding volume was 239 cm3 (median 181 cm3, range 0-943 cm3) without a tissue expander (p < .0001). A similar reduction of irradiated small bowel volume was noted in the conedown fields with the use of a tissue expander (p = .07). Volumes receiving less than full dose irradiation were also less within the initial pelvic (p = .0001) and conedown (p = .002) fields with a tissue expander. Multivariate analysis of patient and treatment-related parameters showed the use of a tissue expander to be the only factor correlated with decreased small bowel volume within the treatment field (p = .003). Morbidity related to placement and removal of the tissue expander was acceptable. Acute radiation-related morbidity was significantly less in patients irradiated with a tissue expander in place (p < .001).

CONCLUSIONS

Placement of an intrapelvic tissue expander was correlated with decreased small bowel volume within the radiotherapy treatment field. Diminished radiation-induced acute gastrointestinal morbidity was noted with use of a tissue expander.

Endometrial cancer with para-aortic adenopathy: patterns of failure and opportunities for cure

PURPOSE

To examine the outcome of patients with advanced endometrial cancer whose para-aortic involvement was diagnosed pathologically or lymphographically.

METHODS AND MATERIALS

Fifty patients from four institutions were treated between 1959 and 1990 with preoperative, post-operative, and primary radiotherapy. Para-aortic disease was diagnosed pathologically in 26 patients and lymphographically in the remaining 24 patients. Pathologically diagnosed patients underwent debulking of grossly involved nodes. All patients received external beam treatment through pelvic and para-aortic portals. Median prescribed dose to the pelvic and para-aortic fields was 50 and 47 Gy, respectively. Those treated with primary or pre-operative irradiation also received intrauterine brachytherapy.

RESULTS

The actuarial 5-year disease-free survival was 46% for all patients. Para-aortic failure was significantly decreased among patients undergoing lymph node resection (13% versus 39%, respectively). Relapse-free survival and pelvic control tended to improve among patients receiving surgery plus irradiation in comparison to those treated by irradiation alone. Distant metastases were most common among patients with high grade lesions.

CONCLUSIONS

Long-term disease-free survival is achievable in endometrial cancer patients with para-aortic lymphadenopathy who are treated with extended-field radiotherapy. Cure is mot attainable among patients with well differentiated, early clinical stage disease who receive combined modality treatment. Survival and local failure are similar for radiologically and pathologically diagnosed patients; however, para-aortic failure as a component of local failure was increased in patients who did not undergo surgical debulking of the adenopathy.

Phase I/II trial of pre-operative radiation therapy and coloanal anastomosis in distal invasive resectable rectal cancer

A total of 22 patients with the diagnosis of invasive, resectable, primary adenocarcinoma of the rectum limited to the pelvis were enrolled on a Phase I/II trial of pre-operative radiation therapy+low anterior resection/coloanal anastomosis. By pre-operative assessment, all patients had invasive tumors involving the distal half of the rectum and required an abdominoperineal resection. The median tumor size was 4 cm (1.5-6 cm) and the median distance from the anal verge was 4 cm (3-7 cm). The whole pelvis received 4680 cGy followed by a 360 cGy boost to the primary tumor bed. The median follow-up was 29 months (10-60 months). Of the 21 patients who underwent resection, 10% had a complete pathologic response and 90% were able to successfully undergo a low anterior resection/coloanal anastomosis. The incidence of local failure as a component of failure was crude: 23% and 4-year actuarial: 32%. The 4-year actuarial survival was 61%. No patients experienced Grade 3 or 4 toxicity while receiving radiation therapy, and 6% developed a partial disruption of the anastomosis. Of the patients who underwent a low anterior resection/coloanal anastomosis, 89% had a good or excellent functional result. This technique may be an alternative to an abdominoperineal resection in selected patients. Further follow-up is needed in order to determine if this approach ultimately has similar local control and survival rates as an abdominoperineal resection.