Follow-up of colorectal cancer and patterns of recurrence.

Colorectal cancer is one of the commonest cancers detected as also amongst the most common causes of cancer death. Survival has improved due to better disease understanding and treatment; however, a substantial proportion of patients recur after curative intent therapy. In this article, we will discuss the imaging features of recurrent colorectal cancer and the role of the radiologist in its management.

Can Post-Treatment MRI Features Predict Pathological Circumferential Resection Margin (pCRM) Involvement in Low Rectal Tumors.

The MERCURY II study demonstrated the use of MRI-based risk factors such as extramural venous invasion (EMVI), tumor location, and circumferential resection margin (CRM) involvement to preoperatively predict pCRM (pathological CRM) outcomes for lower rectal tumors in a mixed group of upfront operated patients and patients who received neoadjuvant treatment. We aim to study the applicability of results of MERCURY II study in a homogeneous cohort of patients who received neoadjuvant chemoradiation (NACTRT) prior to surgery. After Institutional Review Board approval, post NACTRT restaging MRI of 132 patients operated for low rectal cancer between 2014 and 2018 were retrospectively reviewed by two radiologists for site of tumor, EMVI status, distance from anal verge (< 4 or > 4 cm), and mrCRM positivity. Findings were compared with post surgery pCRM outcomes using Fisher's exact test. Only 9/132(7%) patients showed pCRM involvement on histopathology, 8 of them being CRM positive on MRI (p = 0.01). The positive predictive value (PPV) of mrCRM positive status and pCRM status was 12.7% (95% CI: 9.7-16.5%), while the negative predictive value was 98.5% (95% CI: 91.4-99.8%) (p = 0.01). EMVI positive and anteriorly located tumors showed higher incidence of pCRM positivity but were not found to be significant (15% vs 5.2% and p = 0.13 and 8.6% vs 2.1% and p = 0.28, respectively). Unsafe mrCRM was the only factor significantly associated with pCRM positivity on post neoadjuvant restaging MRI. Tumors less than 4 cm from anal verge, anterior tumor location, and mrEMVI positivity did not show statistically significant results to predict pCRM involvement.

Assessment of metastatic risk of gastric GIST based on treatment-naïve CT features.

OBJECTIVE: To study whether the CT features of treatment-naïve gastric GIST may be used to assess metastatic risk. METHODS: In this IRB approved retrospective study, with informed consent waived, contrast enhanced CT images of 143 patients with pathologically confirmed treatment-naïve gastric GIST (74 men, 69 women; mean age 61 years, SD ± 14) were reviewed in consensus by two oncoradiologists blinded to clinicopathologic features and clinical outcome and morphologic features were recorded. The metastatic spread was recorded using available imaging studies and electronic medical records (median follow up 40 months, interquartile range, IQR, 21-61). The association of maximum size in any plane (≤10 cm or >10 cm), outline (smooth or irregular/lobulated), cystic areas (≤50% or >50%), exophytic component (≤50% or >50%), and enhancing solid component (present or absent) with metastatic disease were analyzed using univariate (Fisher's exact test) and multivariate (logistic regression) analysis. RESULTS: Metastatic disease developed in 42 (29%) patients (28 at presentation, 14 during follow-up); 23 (16%) patients died. On multivariate analysis, tumor size >10 cm (p = 0.0001, OR 9.9), irregular/lobulated outline (p = 0.001, OR 5.6) and presence of a enhancing solid component (p < 0.0001, OR 9.1) were independent predictors of metastatic disease. On subgroup analysis, an irregular/lobulated outline and an enhancing solid component were more frequently associated with metastases in tumors ≤5 cm and >5-≤10 cm (p < 0.05). CONCLUSION: CT morphologic features can be used to assess the metastatic risk of treatment-naïve gastric GIST. Risk assessment based on pretreatment CT is especially useful for patients receiving neoadjuvant tyrosine kinase inhibitors and those with tumors <5 cm in size.

MDCT and clinicopathological features of small bowel gastrointestinal stromal tumours in 102 patients: a single institute experience.

OBJECTIVE: Small bowel (SB) is the second most common site of gastrointestinal stromal tumours (GISTs). We evaluated clinical presentation, pathology, imaging features and metastatic pattern of SB GIST. METHODS: Imaging and clinicopathological data of 102 patients with jejunal/ileal GIST treated at Dana-Farber Cancer Institute and Brigham and Women's Hospital (Boston, MA) between 2002 and 2013 were evaluated. Imaging of treatment-naive primary tumour (41 patients) and follow-up imaging in all patients was reviewed. RESULTS: 90/102 patients were symptomatic at presentation, abdominal pain and lower gastrointestinal blood loss being the most common symptoms. On pathology, 21 GISTs were low risk, 17 were intermediate and 64 were high risk. The mean tumour size was 8.5 cm. On baseline CT (n = 41), tumours were predominantly well circumscribed, exophytic and smooth/mildly lobulated in contour. Of 41 tumours, 16 (39%) were homogeneous, whereas 25 (61%) were heterogeneous. Of the 41 tumours, cystic/necrotic areas (Hounsfield units < 20) were seen in 16 (39%) and calcifications in 9 (22%). CT demonstrated complications in 13/41 (32%) patients in the form of tumour-bowel fistula (TBF) (7/41), bowel obstruction (4/41) and intraperitoneal rupture (2/41). Amongst 102 total patients, metastases developed in 51 (50%) patients (27 at presentation), predominantly involving peritoneum (40/102) and liver (32/102). 7/8 (87%) patients having intraperitoneal rupture at presentation developed metastases. Metastases elsewhere were always associated with hepatic/peritoneal metastases. At last follow-up, 28 patients were deceased (median survival, 65 months). CONCLUSION: SB GISTs were predominantly large, well-circumscribed, exophytic tumours with or without cystic/necrotic areas. Complications such as TBF, bowel obstruction and intraperitoneal perforation were visualized at presentation, with patients with perforation demonstrating a high risk of metastatic disease. Exophytic eccentric bowel wall involvement and lack of associated adenopathy are useful indicators to help differentiate GISTs from other SB neoplasms. ADVANCES IN KNOWLEDGE: SB GISTs are predominantly large, well-circumscribed, exophytic tumours, and may present with complications. They often are symptomatic at presentation, are high risk on pathology and metastasize to the peritoneum more commonly than the liver.

Imaging features of primary and metastatic extremity synovial sarcoma: a single institute experience of 78 patients.

OBJECTIVE: To study the appearance of primary and metastatic extremity synovial sarcoma (SS) on cross-sectional imaging. METHODS: In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, the imaging features of 78 patients (42 males and 36 females; mean age, 40 years) with primary and metastatic extremity SS on MRI and multidetector CT were reviewed, with baseline MRI of the primary available in 31 patients. RESULTS: Primary SSs were predominantly well-circumscribed (27/31) and heterogeneously enhancing solid (18/31) or solid-cystic (13/31) tumours. Imaging features visualized included the presence of perilesional oedema (14/31), interfascial (15/31) and intercompartmental extension (7/31), triple sign (11/31), intratumoral haemorrhage (10/31), calcification (6/31), bowl of grapes appearance (5/31) and bone involvement (3/31). Smaller T1 stage tumours (8/31) appeared as heterogeneously enhancing lesions, with some lesions demonstrating interfascial and intercompartmental extension and perilesional oedema. Recurrent/metastatic disease developed in 49/78 (63%) patients. Of these, 20/78 (26%) had metastasis at presentation, while the remaining developed metastatic disease at a median interval of 27 months (range, 3-161 months). Pleuropulmonary metastases (46/78) were the most common sites, with most of the metastases being pleural based. On univariate analysis, larger tumour size, the presence of perilesional oedema, intercompartmental extension, the presence of intralesional haemorrhage and bowl of grapes appearance on MRI were associated with a significantly higher incidence of metastatic disease. CONCLUSION: Certain imaging features of primary SS predict the risk of development of metastatic disease. Imaging features of T1 stage tumours included heterogeneous enhancement, interfascial extension and perilesional oedema. Pleural-based metastases are commonly seen in SSs. ADVANCES IN KNOWLEDGE: Imaging features of primary SS correlate with metastatic disease. Pleural-based metastases are often present in SSs.

Diagnosis and management of intrahepatic cholangiocarcinoma: a comprehensive update for the radiologist.

There is increasing focus on intrahepatic cholangiocarcinoma (IHCC) due to its rising incidence worldwide and relatively poor prognosis, with the revised TNM classification (2009) introducing a separate staging system for IHCC for the first time. In this article, we comprehensively review the current role of the radiologist in the diagnosis and management of patients with IHCC.

Imaging features of primary and metastatic alveolar soft part sarcoma: single institute experience in 25 patients.

OBJECTIVE: To describe imaging features of primary and metastatic alveolar soft part sarcoma (ASPS). METHODS: In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant retrospective study, 25 patients (14 males; mean age, 25 years; range, 18-40 years) with pathologically proven ASPS seen at our institute between 1995 and 2013 were included. Imaging of primary tumours in 5 patients and follow-up imaging in 25 patients were reviewed by 2 radiologists in consensus. Clinical information was obtained from electronic medical records. RESULTS: The most common sites for the primary tumour were extremities (17/25, 68%) and torso (6/25, 24%). Primary tumours (n = 5) were well circumscribed, compared with skeletal muscle, were isodense on CT, hyperintense on T1 and T2 weighted images with intense post-contrast enhancement, prominent feeders on CT and flow voids on MRI. Metastases developed in 23/25 (92%) patients, 18 at presentation. The most common sites of metastases were the lungs (100%), lymph nodes (74%), bones (57%) and brain (43%). Visceral and nodal metastases were hypervascular. At the time of reporting the results, 15 patients have died, 6 are alive and 4 were lost to follow-up. Median survival was 74 months for those without brain metastases (n = 8) and 60 months for those with brain metastases (n = 7). Median survival was shorter for patients with metastases at presentation. CONCLUSION: ASPS most commonly involves the lower extremities of young adults, is hypervascular on imaging, often metastasizes at presentation, frequently to lung, nodes, bones and brain, and has an indolent course despite metastases. Brain metastases and high tumour burden (number of metastatic sites) at presentation decreased survival in our study. ADVANCES IN KNOWLEDGE: ASPS has an unusual pattern of metastases to the brain and nodes in addition to lung and bones. It has an indolent course despite metastases.