How useful is pre-operative computerized tomography scanning in staging rectal cancer?

Local therapy for rectal cancer: still controversial?

PURPOSE

Many considerations, such as morbidity, sexual and urinary dysfunction, or risk of definitive stoma have led to the increased popularity of local therapy in the therapeutic strategy for rectal cancer. However, its role in curative intent is still controversial with oncologic long-term results lower than those obtained by radical surgery.

METHODS

MEDLINE, EMBASE, LILACS, Abstract books, and reference lists from reviews were searched with English language publications to review the current status of evidence for local therapy in rectal cancer, looking especially at the oncologic results and patient selection. We have focused on the new strategies combining neoadjuvant and adjuvant treatment to explain their place in the management of rectal cancer.

RESULTS AND CONCLUSIONS

The key to potentially curative local treatment for rectal cancer is patient selection by identifying the best candidates with preoperative tumor staging and clinical and pathologic assessment of favorable features. Low-risk T1 is suitable for local excision alone. Limited data suggest that adjuvant chemoradiotherapy may be helpful in patients with unfavorable T1 and T2 lesions, achieving a local recurrence rate<20 percent. However, the efficacy of salvage surgery after local excision is uncertain.

Detection of hepatic metastases from cancers of the gastrointestinal tract by using noninvasive imaging methods (US, CT, MR imaging, PET): a meta-analysis

PURPOSE

To perform a meta-analysis to compare current noninvasive imaging methods (ultrasonography [US], computed tomography [CT], magnetic resonance [MR] imaging, and (18)F fluorodeoxyglucose [FDG] positron emission tomography [PET]) in the detection of hepatic metastases from colorectal, gastric, and esophageal cancers.

MATERIALS AND METHODS

A MEDLINE literature search and review of article bibliographies and our institutional charts of patients with colorectal cancer identified data with histopathologic correlation or at least 6 months of patient follow-up. Two authors independently abstracted data sets and excluded data without contingency tables or data published more than once. Summary-weighted estimates of sensitivity were obtained and stratified according to specificity of less than 85% or 85% and higher. A covariate analysis was used to evaluate the influence of patient- or study-related factors on sensitivity.

RESULTS

Among 111 data sets, nine US (509 patients), 25 CT (1,747 patients), 11 MR imaging (401 patients), and nine PET (423 patients) data sets met the inclusion criteria. In studies with a specificity higher than 85%, the mean weighted sensitivity was 55% (95% CI: 41, 68) for US, 72% (95% CI: 63, 80) for CT, 76% (95% CI: 57, 91) for MR imaging, and 90% (95% CI: 80, 97) for FDG PET. Results of pairwise comparison between imaging modalities demonstrated a greater sensitivity of FDG PET than US (P =.001), CT (P =.017), and MR imaging (P =.055).

CONCLUSION

At equivalent specificity, FDG PET is the most sensitive noninvasive imaging modality for the diagnosis of hepatic metastases from colorectal, gastric, and esophageal cancers.

Improved accuracy of computed tomography in local staging of rectal cancer using water enema

A new technique in the preoperative staging computed tomography of rectal cancer using a water enema to promote full distension of the rectum was compared with standard CT in a non-randomised blind study. One hundred and twenty-one patients were enrolled. There were 57 in the water enema CT group and 64 in the standard group. The stage of the disease was assessed following strict criteria and tested against the pathological examination of the resected specimen. Water enema CT was significantly more accurate than standard CT with an accuracy of 84.2% vs. 62.5% (Kappa: 0.56 vs. 0.33: Kappa Weighted: 0.93 vs. 0.84). The diagnostic gain was mainly evident in the identification of rectal wall invasion within or beyond the muscle layer (94.7 vs. 61). The increased accuracy was 33.7% (CL95: 17-49; P < 0.001). The results indicate that water enema CT should replace CT for staging rectal cancer and may offer an alternative to endorectal ultrasound.

Intra-operative ultrasound for the detection of hepatic metastases from colorectal cancer

The aim of this study was to compare the accuracy of intra-operative ultrasound (IOUS) with other imaging modalities and with surgical palpation in detecting liver metastases from colorectal cancer (CRC). Intra-operative ultrasound was performed in 100 patients undergoing surgery for CRC. All patients had pre-operative liver function tests, transcutaneous ultrasound and computerized tomography (CT) scan of the liver. The liver was palpated intra-operatively by a surgeon who was unaware of the pre-operative findings. The liver was then assessed by IOUS. Intra-operative ultrasound detected more patients with metastases than either CT scan, transcutaneous ultrasound or surgical palpation. It also detected a greater number of smaller metastases in these patients and allowed better anatomical definition compared with pre-operative investigations.

Current perspectives in staging large bowel cancer

Today, a standardized method of staging that is internationally accepted is urgently needed for the management of patients with colorectal cancer. The use of a uniform, sensitive staging system would greatly improve case selection and avoid unnecessary bias when entering patients into adjuvant therapy trials. This would allow a more accurate evaluation of new treatment protocols and assist in the development of more effective follow-up programmes.

Use of transrectal ultrasound to evaluate direct tumour spread and lymph node status in patients with rectal cancer

The accuracy of ultrasound in predicting the extent of local tumour spread through the rectal wall and in identifying involved perirectal lymph nodes was evaluated prospectively in 25 patients with rectal cancer. For each patient, the ultrasonic appearances recorded on videotape were compared with operative findings and/or the histology of the tumour. The extent of direct spread was classified into four curable and two incurable categories and was correctly predicted in 20 of 25 patients (80% accuracy). Lymph node status was correctly predicted in 16 of 20 patients (80% accuracy). These results suggest that pre-operative assessment of patients with rectal cancer using transrectal ultrasound is a useful technique which may assist the surgeon in his choice of operation and in the selection of those patients who may benefit from pre-operative radiotherapy.