The potential predictive value of MRI and PET-CT in mucinous and nonmucinous rectal cancer to identify patients at high risk of metastatic disease.

Abstract

OBJECTIVE:

To correlate imaging parameters from baseline MRI diffusion-weighted imaging (DWI) and fludeoxyglucose (FDG) positron emission tomography (PET)-CT with synchronous and metachronous metastases in mucinous carcinoma (MC) and non-mucinous carcinoma (NMC) rectal cancer.

METHODS:

111 patients with extraperitoneal locally advanced rectal cancer, who underwent pelvic MRI, DWI and FDG PET-CT, were stratified into MC (n = 23) and NMC (n = 88). We correlated adverse morphologic features on MRI [mT4, mesorectal fascia involvement, extramural venous invasion (mEMVI), mN2] and quantitative imaging parameters [minimum apparent diffusion coefficient (ADCmin), maximum standardized uptake value, total lesion glycolysis, metabolic tumour volume, T2 weighted and DWI tumour volumes] with the presence of metastatic disease. All patients underwent pre-operative chemoradiation therapy (CRT); 100/111 patients underwent surgery after CRT and were classified as pathological complete response (PCR) and no PCR [tumour regression grade (TRG)1 vs TRG2-5] and as ypN0 and ypN1-2. Median follow-up time was 48 months. Metastases were confirmed on FDG PET-CT and contrast-enhanced multidetector CT.

RESULTS:

The percentage of mucin measured by MRI correlates with that quantified by histology. On multivariate analysis, the synchronous metastases were correlated with mEMVI [odds ratio (OR) = 21.48, p < 0.01] and low ADCmin (OR = 0.04, p = 0.038) in NMC. The difference of metachronous recurrence between the MC group (10-90% mucin) and NMC group was significant (p < 0.01) (OR = 21.67, 95% confidence interval 3.8-120.5). Metachronous metastases were correlated with ypN2 (OR = 8.24, p = 0.01) in MC and in NMC. In NMC, mEMVI correlated with no PCR (p = 0.018) and ypN2 (p < 0.01).

CONCLUSION:

mEMVI could identify patients with NMC, who are at high risk of synchronous metastases. The MC group is at a high risk of developing metachronous metastases. Advances in knowledge: Patients at high risk of metastases are more likely to benefit from more aggressive neoadjuvant therapy.

• Authors: Brunella Barbaro, Lucia Leccisotti, Fabio M Vecchio, Marialuisa Di Matteo, Teresa Serra, Marco Salsano, Andrea Poscia, Claudio Coco, Roberto Persiani, Sergio Alfieri, Maria Antonietta Gambacorta, Vincenzo Valentini, Alessandro Giordano, Lorenzo Bonomo
• Journal: The British journal of radiology (Br J Radiol) Vol. 90 Issue 1069 Pg. 20150836 (Jan 2017) ISSN: 1748-880X [Electronic] England
• PMID: 27845566 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Fluorodeoxyglucose F18

Topics

• Adenocarcinoma, Mucinous (diagnosis, mortality, pathology, therapy)
• Adult
• Aged
• Aged, 80 and over
• Chemoradiotherapy (methods)
• Cohort Studies
• Diffusion Magnetic Resonance Imaging (methods)
• Disease-Free Survival
• Female
• Fluorodeoxyglucose F18
• Humans
• Kaplan-Meier Estimate
• Male
• Middle Aged
• Multimodal Imaging (methods)
• Neoplasm Invasiveness (pathology)
• Neoplasm Metastasis
• Neoplasm Staging
• Neoplasms, Second Primary (diagnosis, mortality, pathology, therapy)
• Positron Emission Tomography Computed Tomography (methods)
• Predictive Value of Tests
• Prospective Studies
• Rectal Neoplasms (diagnosis, mortality, pathology, therapy)
• Risk Assessment
• Statistics, Nonparametric
• Survival Analysis