الفهرس 
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Abstract
Imaging plays an important role in the workup of patients with gastrointestinal tract (GIT) hepatic metastases; and computed tomography (CT) is the most commonly used imaging modality for hepatic imaging in these patients.
Conventionally, CT evaluation of response to treatment in solid tumors has made use of the response evaluation criteria in solid tumors (RECIST) guidelines. Studies have shown the inadequacy of RECIST in assessing treatment response. To overcome these inadequacies, several alternative criteria have been proposed that take morphology as well as size into account in patients with gastrointestinal stromal tumors & patients undergoing systemic therapy for renal cell carcinoma or colorectal liver metastases.
The present study is designed to evaluate the use of contrast enhanced computed tomography (CECT) size-based & morphologic criteria {Non-size-based response criteria} to assess response to chemotherapy in patients with GIT liver metastases and its association with clinical, tumor marker response & overall survival.
This cohort study was prospectively & retrospectively conducted on 40 patients (35 prospective & 5 retrospective). They were 25 males & 15 females whose ages ranged from 28 to 76 years (mean age 57.55 years). It includes GIT cancer patients with liver metastases (stage IV) who are candidates for chemotherapy.
The diagnosis of GIT liver metastases in these patients was established based on CECT with or without biopsy.
The patients were classified as; 19 patients with pancreatic cancer, 13 with colorectal cancer, 6 with Gastro esophageal cancer, 2 with biliary cancer.
The patients received 3-6 chemotherapy cycles followed by repeated physical examination, CECT and tumor markers assessment. The hepatic lesions were then evaluated by both RECIST and morphological response criteria.
Our results showed that the statistical relationship between morphologic response and tumor marker response of patients (P =0.002) was more significant than that with RECIST response (P =0.022). The statistical relationship between morphologic response and overall survival of patients (P =0.001) was more significant than that with RECIST response (P =0. 002). There was significant statistical relationship between RECIST response and clinical response of patients (P =0.043), while there is no significant statistical relationship between morphologic response and clinical response of patients (P =0. 087). Discordance was seen between morphologic response & RECIST response (P=0.281). Pretreatment size of tumor ≤ 3 cm (odds ratio, 1.8) was a predictive factor for optimal morphologic response to systemic chemotherapy.
We concluded that:
Morphologic changes independent of change in tumor size, identifiable on single-phase and triphasic CECT form the basis for morphologic response. These morphological criteria are a useful, non-invasive marker of tumor response in patients with GIT liver metastases receiving chemotherapy and need to be incorporated to treatment evaluation.
The discordance between morphologic and RECIST based responses indicates that both evaluation methods need to be implemented.
Some studies have focused on tumor perfusion by CT and MRI on evaluating response to new types of chemotherapy; however, these techniques are complex and not yet available for routine evaluation. In contrast to morphological criteria which can be applied to single phase CT technique and therefore triphasic liver protocol CT is not necessarily required.
The limitations of our study were that:
In the retrospective part of our study, some patients had poor quality images.
Not all patients presented for follow up exactly after 3 or 6 cycles of chemotherapy.
Morphologic response may be difficult to assess when a tumor is very small (usually less than 1cm) due to partial volume effect.
We finally recommend that:
Imaging techniques should be standardized to apply these criteria for the assessment of patients with GIT liver metastases.
Morphologic and RECIST criteria should be integrated to improve the accuracy of current radiologic response evaluation.