Effects of radiotherapy on oral cavity tissues

Radiotherapy in the treatment of head and neck tumors is most often used as an independent method or in combination with surgery and / or chemotherapy. These therapeutic methods in a multidisciplinary approach generally lead to favourable therapeutic response. During radiotherapy of this region, oral mucosa is inevitably covered within irradiated volume. Radical therapy is achieved with high doses of radiation, which usually results in development of undesired toxic effects, which, depending on the time of manifestation can be acute and late. Acute radiation toxicity occurs during or immediately after completion of performed therapy, and the late one several months or years after the completed treatment. The most common acute complications in the oral cavity are inflammation of oral mucosa, loss of taste, dry mouth and secondary infections. Late complications include radiation caries, trismus, and osteoradionecrosis. The aim of this paper was to present the effects and specificities of toxicity observed on oral cavity tissues after radiotherapy

Comparison of Different Machine Learning Models in Prediction of Postirradiation Recurrence in Prostate Carcinoma Patients

After primary treatment of localized prostate carcinoma (PC), up to a third of patients have disease recurrence. Different predictive models have already been used either for initial stratification of PC patients or to predict disease recurrence. Recently, artificial intelligence has been introduced in the diagnosis and management of PC with a potential to revolutionize this field. The aim of this study was to analyze machine learning (ML) classifiers in order to predict disease progression in the moment of prostate-specific antigen (PSA) elevation during follow-up. The study cohort consisted of 109 PC patients treated with external beam radiotherapy alone or in combination with androgen deprivation therapy. We developed and evaluated the performance of two ML algorithms based on artificial neural networks (ANN) and naive Bayes (NB). Of all patients, 72.5% was randomly selected for a training set while the remaining patients were used for testing of the models. The presence/absence of disease progression was defined as the output variable. The input variables for models were conducted from the univariate analysis preformed among two groups of patients in the training set. They included two pretreatment variables (UICC stage and Gleason's score risk group) and five posttreatment variables (nadir PSA, time to nadir PSA, PSA doubling time, PSA velocity, and PSA in the moment of disease reevaluation). The area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, negative predictive value, and predictive accuracy was calculated to test the models' performance. The results showed that specificity was similar for both models, while NB achieved better sensitivity then ANN (100.0% versus 94.4%). The ANN showed an accuracy of 93.3%, and the matching for NB model was 96.7%. In this study, ML classifiers have shown potential for application in routine clinical practice during follow-up when disease progression was suspected

Pojava recidiva karcinoma rektuma u odnosu na pol ispitanika

Colorectal cancer is the most frequent gastrointestinal tumor, very often situated in the rectum. Serbia is for long period of time in group of European countries with average incidence and high mortality of rectal cancer. Aim: To investigate if histopathological type and grade of cancer and time before local recurrence depend on patients' sex, considering that rectal cancer is more often present in male than in female. Material and methods: A retrospective study (2004‒2013.) included 49 patients from Institute for oncology and radiology in Belgrade, with locally recurrent rectal cancer (29 male and 20 female). All the patients with primary rectal cancer had surgical treatment; postoperative adjuvant chemotherapy was applied in 25 patients. Results: Mean age of our patients is 68 years (min 32, max 84 years). Recurrent rectal cancer is most frequent in group 70‒79 years, both in men and women. Adenocarcinoma is histopathological type of rectal cancer in 96% of patients. The most frequent HP grade is moderately differentiated tumor, grade II (p lt 0,0001). Local recurrences appear within two years after surgery (p=0,0109). Conclusion: We didn't establish correlation between histopathological type and grade of rectal cancer and period of local recurrence related to patients' sex. Given the prevalence of both sexes, screening of patients, adequate diagnosis and timely treatment are most important.Karcinomi debelog creva su najčešći tumori digestivnog trakta sa veoma čestom lokalizacijom u rektumu. Naša zemlja se već duži niz godina nalazi u grupi evropskih zemalja sa srednje visokim stopama obolevanja i visokim stopama smrtnosti od ovog karcinoma. Cilj: Utvrditi da li histopatološki tip i gradus karcinoma i vreme do pojave recidiva zavise od pola pacijenta, s obzirom na to da je karcinom rektuma češće prisutan kod muškaraca nego kod žena. Materijal i metode: U retrospektivnu studiju koja obuhvata period od 2004. do 2013. godine uključeno je 49 pacijenata Instituta za onkologiju i radiologiju u Beogradu sa recidivima karcinoma rektuma (29 muškaraca i 20 žena). Svi bolesnici sa primarnim karcinomom rektuma bili su operisani, a postoperativno je sprovedena adjuvantna hemioterapija kod 25 pacijenata. Rezultati: Prosečna starost naših ispitanika bila je 68 godina (najmlađi pacijent imao je 32 godine, a najstariji 84). Najveća učestalost recidiva karcinoma rektuma je u starosnoj grupi 70‒79 godina kod oba pola. Kod 96% pacijenata histopatološki tip tumora je adenokarcinom. Najčešći histopatološki gradus tumora u ispitanoj grupi je srednje diferentovani tumor, gradus II (p lt 0,0001). Recidivi su se uglavnom javljali u prve dve godine nakon operacije (p=0,0109). Zaključak: Nije utvrđena statistički značajna razlika između histopatološkog tipa i gradusa karcinoma rektuma i vremena od operacije do pojave recidiva u odnosu na pol pacijenata. S obzirom na rasprostranjenost bolesti kod oba pola zaključujemo da je radi pravovremenog lečenja najvažniji skrining pacijenata i adekvatna dijagnostika