Dosimetric parameters that predict late rectal complications after curative radiotherapy in patients with uterine cervical carcinoma

Abstract

Expertise‐seeking research studies how people search for expertise and choose whom to contact in the context of a specific task. An important outcome are models that identify factors that influence expert finding. Expertise retrieval addresses the same problem, expert finding, but from a system‐centered perspective. The main focus has been on developing content‐based algorithms similar to document search. These algorithms identify matching experts primarily on the basis of the textual content of documents with which experts are associated. Other factors, such as the ones identified by expertise‐seeking models, are rarely taken into account. In this article, we extend content‐based expert‐finding approaches with contextual factors that have been found to influence human expert finding. We focus on a task of science communicators in a knowledge‐intensive environment, the task of finding similar experts, given an example expert. Our approach combines expertise‐seeking and retrieval research. First, we conduct a user study to identify contextual factors that may play a role in the studied task and environment. Then, we design expert retrieval models to capture these factors. We combine these with content‐based retrieval models and evaluate them in a retrieval experiment. Our main finding is that while content‐based features are the most important, human participants also take contextual factors into account, such as media experience and organizational structure. We develop two principled ways of modeling the identified factors and integrate them with content‐based retrieval models. Our experiments show that models combining content‐based and contextual factors can significantly outperform existing content‐based models.

A prospective observational study with dose volume parameters predicting rectosigmoidoscopic findings and late rectosigmoid bleeding in patients with uterine cervical cancer treated by definitive radiotherapy

“…The D RP , RP ratio (D RP /D Point A ), and maximal rectal point dose were used to evaluate the risk of LRC traditionally [11,13-17]. We previously showed that the biologically effective dose at the ICRU rectal point (≤125 vs. >125 Gy 3 ) calculated at the orthogonal film-based brachytherapy was equivalent to an EQD2 of 75 Gy 3 , and was significantly associated with a 5-year actual risk of an LRC grade ≥2 (5.4 vs. 36.1%; p  < 0.001) [11].…”

“…For evaluating RMC, we adopted an endoscopic scoring system [8,10] and determined the worst score through the whole wall of the rectosigmoid colon among all serial examinations. LRC was classified according to the Radiation Therapy Oncology Group (RTOG) late radiation morbidity scoring criteria [11]. …”

The usefulness of fleet rectal enemas on high-dose-rate intracavitary cervical cancer brachytherapy. A prospective trial

“…The rectum is the main organ at risk (OAR) for complications [5]. Classically, rectal and bladder points on orthogonal radiographs have represented the doses to these organs and have been used to estimate the risk of complications [6]. These points only provide a limited information of the OAR anatomy and its relationship with the brachytherapy applicator.…”

“…Up to 23% of the patients can experience rectal toxicity grade 2 or higher [8]. Higher doses per fraction and higher doses at point A have been shown to increase rectal toxicity [6]. …”

The association of rectal equivalent dose in 2 Gy fractions (EQD2) to late rectal toxicity in locally advanced cervical cancer patients who were evaluated by rectosigmoidoscopy in Faculty of Medicine, Chiang Mai University

“…For cervical cancer, the cumulative dose to rectum and bladder in terms of BED correlated to rectal toxicity [21,22]. …”