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Purpose: Magnetic resonance imaging (MRI) with the help of MRI-based tumor regression grade (mrTRG) score has been used as a tool to predict pathological tumor regression grade (pTRG) in patients of rectal cancer post-neoadjuvant chemoradiation. Our study aims to evaluate the ability of MRI in assessing treatment response comparing an objective mrTRG score and a subjective Likert score, with a focus on the ability to predict pathologic complete response (pCR). Methods: Post-treatment MRI studies were retrospectively reviewed for 170 consecutive cases of histopathologically proven rectal cancer after receiving neoadjuvant chemoradiation and prior to surgery by two oncoradiologists blinded to the eventual postoperative histopathology findings. An objective (mrTRG) and a subjective Likert score were assigned to all the cases. Receiver operating characteristic curves were constructed to determine the ability of Likert scale and mrTRG to predict pCR, with postoperative histopathology being the gold standard. The optimal cutoff points on the scale of 1 to 5 were obtained for mrTRG and Likert scale with the greatest sum of sensitivity and specificity using the Youden Index. Results: The most accurate cutoff point for the mrTRG to predict complete response was 2.5 (using Youden index), with a sensitivity of 69.2%, specificity of 69.6%, positive predictive value (PPV) of 85.6%, negative predictive value (NPV) of 46.4%, and accuracy of 69.3%. The most accurate cutoff for the Likert scale to predict complete response was 3.5, with a sensitivity of 47.5%, specificity of 89.1%, PPV of 91.9%, NPV of 39.4%, and accuracy of 59%. mrTRG had a lower cutoff and was more accurate in predicting pCR compared to Likert score. Conclusion: An objective mrTRG was more accurate than a subjective Likert scale to predict complete response in our study.
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Background Presence of extramural venous invasion (EMVI) is a poor prognostic factor for rectal cancer as per literature. However, India-specific data are lacking. Aim The aim of the study is to determine the prognostic significance of EMVI in locally advanced rectal cancer on baseline MRI. Materials and Methods We retrospectively reviewed 117 MRIs of operable non-metastatic locally advanced rectal cancers in a tertiary cancer institute. Three dedicated oncoradiologists determined presence or absence of EMVI, and its length and thickness, in consensus. These patients were treated as per standard institutional protocols and followed up for a median period of 37 months (range: 2-71 months). Kaplan-Meier curves (95% CI) were used to determine disease-free survival (DFS), distant-metastases free survival (DMFS), and overall survival (OS). Univariate analysis was performed by comparing groups with log-rank test. Results EMVI positive cases were 34/114 (29%). More EMVI-positive cases developed distant metastasis compared with EMVI-negative cases (14/34-41% vs. 22/83-26%). The difference, however, was not statistically significant ( p = 0.146). After excluding signet-ring cell cancers ( n = 14), EMVI showed significant correlation with DMFS ( p = 0.046), but not with DFS or OS. The median thickness and length of EMVI was 6 and 14 mm, respectively in patients who developed distant metastasis, as compared with 5 and 11 mm in those who did not, although this difference was not statistically significant. Conclusion EMVI is a predictor of distant metastasis in locally advanced non-metastatic, non-signet ring cell rectal cancers. EMVI can be considered another high-risk feature to predict distant metastasis.
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OBJECTIVE: To document the mammographic changes after neoadjuvant chemotherapy with histopathological correlation, to calculate the accuracy of mammography (MG) in predicting residual tumour size and to measure the interobserver agreement in reading mammograms. METHODS: In 446 consecutive cases, the pre- and post-chemotherapy mammograms were retrospectively evaluated by two blinded observers, and consensus findings were compared with reference standard of surgical specimen. The accuracy of MG in predicting residual tumour size was calculated. Kappa statistics were calculated for measuring the interobserver agreement for reading mammograms. The sensitivity, specificity, positive-predictive value and negative-predictive value for the prediction of residual disease were calculated. RESULTS: The most common primary abnormalities were mass lesions without and with microcalcifications. After chemotherapy, there was decrease in size of most (95.1%) of the measurable masses, with decrease in the mean tumour size from 4.1 to 2.5 cm. The density of the tumour decreased in 66.6% (241/362) cases with residual disease. There was almost perfect interobserver agreement for describing the primary abnormality in the pre- as well as post-chemotherapy mammograms (k = 0.87 and 0.81, respectively) with substantial agreement for measurement of the mass lesions before and after chemotherapy (k = 0.69 and 0.68, respectively). MG showed accuracy of 60.0%, sensitivity of 94.4%, specificity of 50.0%, positive-predictive value of 91.3% and negative-predictive value of 61.8%. CONCLUSION: MG remains a highly sensitive and reproducible investigation for the assessment of residual disease after chemotherapy. ADVANCES IN KNOWLEDGE: There is substantial interobserver agreement in characterizing and measuring breast tumours on mammograms.
