[Preoperative radiotherapy for rectal cancer: target volumes]

Nanotechnology in diagnosis and therapy of gastrointestinal cancer

Advances in nanotechnology have opened new frontiers in the diagnosis and treatment of cancer. Nanoparticle-based technology improves the precision of tumor diagnosis when combined with imaging, as well as the accuracy of drug target delivery, with fewer side effects. Optimized nanosystems have demonstrated advantages in many fields, including enhanced specificity of detection, reduced toxicity of drugs, enhanced effect of contrast agents, and advanced diagnosis and therapy of gastrointestinal (GI) cancers. In this review, we summarize the current nanotechnologies in diagnosis and treatment of GI cancers. The development of nanotechnology will lead to personalized approaches for early diagnosis and treatment of GI cancers.

Evaluation of mesalazine polymeric conjugate in the treatment of actinic proctitis in rats

Purpose:

The present study aimed at testing a new formulation of mesalazine linked to chondroitin sulfate and its components alone in the treatment of actinic proctitis in rats.

Methods:

Forty-seven female Wistar rats were submitted to pelvic radiation and divided into eight groups: control A, mesalazine A, chondroitin A, and conjugate A, gavage of the according substance two weeks after irradiation and sacrifice three weeks after oral treatment; control C, mesalazine C, chondroitin C, and conjugate C, sacrifice six weeks after oral treatment. The rectum was submitted to histological characterization for each of the findings: inflammatory infiltrate, epithelial degeneration, mucosal necrosis, and fibrosis.

Results:

The inflammatory infiltrate was more intense in chondroitin A, mesalazine A, and conjugate C. The collagen deposition was less intense in chondroitin A, and mesalazine A, and more intense in control C.

Conclusions:

Mesalazine and chondroitin alone were efficacious in inducing a delayed inflammatory response, hence reducing the late fibrosis. The conjugate was able to induce an ever more delayed inflammatory response.

Mismatch Repair System Deficiency Is Associated With Response to Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

PURPOSE

Defective mismatch repair system (dMMR) has been shown to have a favorable impact on outcome in patients with colorectal cancer treated with surgery or immunotherapy, with adjuvant chemotherapy being discouraged unless there is nodal involvement. Its impact on radiosensitivity is unknown in patients with colorectal cancer.

METHODS AND MATERIALS

Patients treated for locally advanced rectal cancer between 2000 and 2016 were studied. Reported points included age, sex, clinical and radiologic tumor stages at diagnosis, modalities of neoadjuvant treatment, posttreatment pathologic staging, tumor regression score, and local, distant relapse-free, and overall survival. An inverse probability of treatment weighting propensity score analysis was performed to evaluate the association of mismatch repair proficiency with surgical and clinical outcomes.

RESULTS

Among the 296 patients included, 23 (7.8%) had dMMR. Median follow-up was 43.0 months (interquartile range, 27.9-66.7). Patients with dMMR were significantly younger than the others. After inverse probability of treatment weighting propensity score matching, dMMR patients had higher pathologic downstaging rate (P < .0001), higher tumor regression grade (P = .024), and a longer recurrence-free survival (P < .0001).

CONCLUSIONS

dMRR was associated with significant tumor downstaging after neoadjuvant chemoradiation and with increased recurrence-free survival. dMMR patients may have more radiosensitive tumors.

Automatic segmentation software in locally advanced rectal cancer: READY (REsearch program in Auto Delineation sYstem)-RECTAL 02: prospective study

To validate autocontouring software (AS) in a clinical practice including a two steps delineation quality assurance (QA) procedure.

The existing delineation agreement among experts for rectal cancer and the overlap and time criteria that have to be verified to allow the use of AS were defined.

Median Dice Similarity Coefficient (MDSC), Mean slicewise Hausdorff Distances (MSHD) and Total-Time saving (TT) were analyzed.

Two expert Radiation Oncologists reviewed CT-scans of 44 patients and agreed the reference-CTV: the first 14 consecutive cases were used to populate the software Atlas and 30 were used as Test.

Each expert performed a manual (group A) and an automatic delineation (group B) of 15 Test patients.

The delineations were compared with the reference contours.

The overlap between the manual and automatic delineations with MDSC and MSHD and the TT were analyzed.

Three acceptance criteria were set: MDSC ≥ 0.75, MSHD ≤1mm and TT sparing ≥ 50%.

At least 2 criteria had to be met, one of which had to be TT saving, to validate the system.

The MDSC was 0.75, MSHD 2.00 mm and the TT saving 55.5% between group A and group B. MDSC among experts was 0.84.

Autosegmentation systems in rectal cancer partially met acceptability criteria with the present version.