Restaging rectal cancer following neoadjuvant chemoradiotherapy

Correct tumour restaging is pivotal for identifying the most personalised surgical treatment for patients with locally advanced rectal cancer undergoing neoadjuvant therapy,and works to avoid both poor oncological outcome and overtreatment.Digital rectal examination,endoscopy,and pelvic magnetic resonance imaging are the recommended modalities for local tumour restaging,while chest and abdominal computed tomography are utilised for the assessment of distant disease.The optimal length of time between neoadjuvant treatment and restaging,in terms of both oncological safety and clinical effectiveness of treatment,remains unclear,especially for patients receiving prolonged total neoadjuvant therapy.The timely identification of patients who are radioresistant and at risk of disease progression remains challenging.

How reliable is current imaging in restaging rectal cancer after neoadjuvant therapy?

In patients with advanced rectal cancer,neoadjuvant chemo radiotherapy provides tumor downstaging and downsizing and complete pathological response in up to 30%of cases.After proctectomy complete pathological response is associated with low rates of local recurrence and excellent long term survival.Several authors claim a less invasive surgery or a non operative policy in patients with partial or clinical complete response respectively,however to identify patients with true complete pathological response before surgical resection remains a challenge.Current imaging techniques have been reported to be highly accurate in the primary staging of rectal cancer,however neoadjuvant therapy course produces deep modifications on cancer tissue and on surrounding structures such as overgrowth fibrosis,deep stroma alteration,wall thickness,muscle disarrangement,tumor necrosis,calcification,and inflammatory infiltration.As a result,the same imaging techniques,when used for restaging,are far less accurate.Local tumor extent may be overestimated or underestimated.The diagnostic accuracy of clinical examination,rectal ultrasound,computed tomography,magnetic resonance imaging,and positron emission tomography using 18F-fluoro-2’-deoxy-Dglucose ranges between 25%and 75%being less than 60%in most studies,both for rectal wall invasion and for lymph nodes involvement.In particular the ability to predict complete pathological response,in order to tailor the surgical approach,remains low.Due to the radio-induced tissue modifications,combined with imaging technical aspects,low rate accuracy is achieved,making modern imaging techniques still unreliable in restaging rectal cancer after chemo-radiotherapy.

Value of transrectal ultrasonography for tumor node metastasis restaging in patients with locally advanced rectal cancer after neoadjuvant chemoradiotherapy

Objective:To explore the value of transrectal ultrasonography(TRUS)for tumor node metastasis(TNM)restaging for patients with locally advanced rectal cancer after neoadjuvant chemoradiotherapy(neo-CRT).Methods:One hundred and forty-nine patients with locally advanced rectal cancer(cT3-4 or cN+)who underwent TRUS after neo-CRT were retrospectively reviewed.TRUS restaging was compared with the results of post-operative pathological TNM findings.Results:After neo-CRT,the accuracy of TRUS for diagnosing T-staging was 30.9%,with 60.4%(90/149)of cases overestimated.The sensitivity of TRUS for T-staging(T0 vs T1 vs T2 vs T3 vs T4)were 16.3%,0%,12.5%,42.6%and 75.0%,respectively.The accuracy of TRUS for diagnosing N-staging after neo-CRT was 81.2%,with the sensitivities of N0 and N+were 93.3%and 31.0%,respectively.After neo-CRT,27.5%(41/149)of patients achieved pathologically complete response(pCR).The sensitivity,specificity,positive predictive value and negative predictive values of TRUS for pCR were 17.1%,99.1%,87.5%and 75.9%,respectively.Conclusions:TRUS can be applied for restaging T4 and N0,and has potential for screening out patients with pCR in those with locally advanced rectal cancer after neo-CRT,although some stages are overestimated for T-staging and its sensitivity for predicting pCR is low.

Multidisciplinary treatment of rectal cancer in 2014: Where are we going?

In the present review we discuss the recent developments and future directions in the multimodal treatment of locally advanced rectal cancer, with respect to staging and re-staging modalities, to the current role of neoadjuvant chemo-radiation and to the conservative and more limited surgical approaches based on tumour response after neoadjuvant combined therapy. When initial tumor staging is considered a high accuracy has been reported for T pre-treatment staging, while preoperative lymph node mapping is still suboptimal. With respect to tumour re-staging, all the current available modalities still present a limited accuracy, in particular in defining a complete response. The role of short vs long-course radiotherapy regimens as well as the optimal time of surgery are still unclear and under investigation by means of ongoing randomized trials. Observational management or local excision following tumour complete response are promising alternatives to total mesorectal excision, but need further evaluation, and their use outside of a clinical trial is not recommended.The preoperative selection of patients who will benefit from neoadjuvant radiotherapy or not, as well as the proper identification of a clinical complete tumour response after combined treatment modalities,will influence the future directions in the treatment of locally advanced rectal cancer.

FDG-PET/CT and parathyroid carcinoma:Review of literature and illustrative case series

Parathyroid cancer is an uncommon malignant cancer and is associated with a poor prognosis.The staging of parathyroid cancer represents an important issue both at initial diagnosis and after surgery and medical treatment.The role of positron emission tomography/computed tomography(PET/CT)with 18F-Fluorodeoxyglucose(18F-FDG)as an imaging tool in parathyroid cancer is not clearly reported in the literature,although its impact in other cancers is well-defined.The aim of the following illustrative clinical cases is to highlight the impact of PET/CT in the management of different phases of parathyroid cancer.We describe five patients with parathyroid malignant lesions,who underwent FDG PET/CT at initial staging,restaging and post-surgery evaluation.In each patient we report the value of PET/CT comparing its findings with other common imaging modalities(e.g.,CT,planar scintigraphy with 99mTcsestamibi,magnetic resonance imaging)thus determining the complementary benefit of FDG PET/CT in parathyroid carcinoma.We hope to provide an insight into the potential role of PET/CT in assessing the extent of disease and response to treatment which are the general principles used to correctly evaluate disease status.

Clinical value of ^(18)F-FDG PET/CT in assessing suspicious relapse after rectal cancer resection

AIM:To evaluate the value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography(18F-FDG PET/CT) in the restaging of resected rectal cancer.METHODS:From January 2007 to Sep 2008,21 patients who had undergone curative surgery resection for rectal carcinoma with suspicious relapse in conventional imaging or clinical findings were retrospectively enrolled in our study.The patients underwent 28 PET/CT scans(two patients had two scans,one patient had three and one had four scans).Locoregional recurrences and/or distant metastases were confirmed by histological analysis or clinical and imaging follow-up.RESULTS:Final diagnosis was confirmed by histopathological diagnosis in 12 patients(57.1) and by clinical and imaging follow-up in nine patients(42.9).Eight patients had extrapelvic metastases with no evidence of pelvic recurrence.Seven patients had both pelvic recurrence and extrapelvic metastases,and two patients had pelvic recurrence only.18F-FDG PET/CT was negative in two patients and positive in 19 patients.18F-FDG PET/CT was true positive in 17 patients and false positive in two.The accuracy of 18F-FDG PET/CT was 90.5,negative predictive value was 100,and positive predictive value was 89.5.Five patients with perirectal recurrence underwent 18F-FDG PET/CT image guided tissue core biopsy.18F-FDG PET/CT also guided surgical resection of pulmonary metastases in three patients and monitored the response to salvage chemotherapy and/or radiotherapy in four patients.CONCLUSION:18F-FDG PET/CT is useful for evaluating suspicious locoregional recurrence and distant metastases in the restaging of rectal cancer after curative resection.

Multimodal imaging evaluation in staging of rectal cancer

Rectal cancer is a common cancer and a major cause of mortality in Western countries.Accurate staging is essential for determining the optimal treatment strategies and planning appropriate surgical procedures to control rectal cancer.Endorectal ultrasonography(EUS)is suitable for assessing the extent of tumor invasion,particularly in early-stage or superficial rectal cancer cases.In advanced cases with distant metastases,computed tomography(CT)is the primary approach used to evaluate the disease.Magnetic resonance imaging(MRI)is often used to assess preoperative staging and the circumferential resection margin involvement,which assists in evaluating a patient’s risk of recurrence and their optimal therapeutic strategy.Positron emission tomography(PET)-CT may be useful in detecting occult synchronous tumors or metastases at the time of initial presentation.Restaging after neoadjuvant chemoradiotherapy(CRT)remains a challenge with all modalities because it is difficult to reliably differentiate between the tumor mass and other radiation-induced changes in the images.EUS does not appear to have a useful role in post-therapeutic response assessments.Although CT is most commonly used to evaluate treatment responses,its utility for identifying and following-up metastatic lesions is limited.Preoperative high-resolution MRI in combination with diffusion-weighted imaging,and/or PET-CT could provide valuable prognostic information for rectal cancer patients with locally advanced disease receiving preoperative CRT.Based on these results,we conclude that a combination of multimodal imaging methods should be used to precisely assess the restaging of rectal cancer following CRT.

3-19 Study of PRESTAGE Sensitivity to Variation of Input Parameters

PRESTAGE is a Monte Carlo simulation code which calculates proton single event effect cross sections from heavy ion test data. It can accurately predict not only single event upsets induced by proton indirect ionization,but also single event latch-ups and proton direct ionization effects[1]. However, in practical applications some of the input parameters are difficult to obtain. For instance, the thickness of the sensitive volume is closely related to the topology, doping concentration, and other device parameters. Device suppliers are generally reluctant to disclose such information due to the consideration of intellectual property protection. Therefore, examining the sensitivity to the input parameters is important to the usage of the PRESTAGE method.