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  • br The chronic radiation toxicity which usually

    2020-07-29


    The chronic radiation toxicity, which usually presents a few months or even years after the irradiation, affects not only the parenchymal NPS-2143 in the rectum, but also the vascular endothelial cells, mainly small blood vessels and arterioles, and even fibro-blasts, leading to the formation of thrombi, the occlusion of arte-rioles and fibrosis in the rectum [27]. These events potentially affect the healing of a future colorectal anastomosis. External-beam ra-diation causes more damaging effects on its surrounding tissue than brachytherapy. Data from the NPCR show that only 4% of the irradiated patients with prostate cancer received brachytherapy alone, while 96% of the patients with prostate cancer received external-beam RT, either alone or in combination with brachy-therapy [28], possibly explaining some of the leaks reported. 
    In our study, the median distance from the tumour to the anal verge was 7 cm, and the mean delay from radiation therapy to surgery with AR was 73 months in the RT-prost group; however, these patients did not have a more advanced stage than did those in the RT-rect group.
    We did not find any increase in AL among patients with stage IV rectal cancer treated with RT and operated with AR, even though some retrospective data in the literature suggest such an increase [29]. However, there was an increased risk for AL (OR, 8.72) in patients with stage IV rectal cancer who had been previously treated with RT for prostate cancer, even though this is probably a highly selective group of patients.
    This was the largest study to date on this subject, as it included 188 patients with bowel resected rectal cancer who were previ-ously irradiated for prostate cancer; among them, 59 patients were resected and reconstructed with an anastomosis. The two regis-tries, the SCRCR and NPCR, from which we collected the data, have been validated, have almost complete coverage and collect data
    Table 3
    Clinical characteristics and post-operative complications in patients who underwent anterior resection and had previously received radiotherapy for prostate cancer after the review of medical records.
    AR
    Anastomotic leakage 12 (20) Grade A 6
    Grade B 5
    Grade C 1
    AR, anterior resection; ASA, American Society of Anesthesiologists; SD, standard deviation; RT, radiotherapy; CRT, chemoradiotherapy.
    prospectively.
    This study had some limitations because of the inherent weakness of registry-based studies. Despite previous validation, the review of patient records revealed that four patients were registered as having the wrong type of operation. A study of the validity of the SCRCR between 1996 and 2000 performed by Gun-narsson et al. showed that its validity is acceptable regarding severe complications such as AL (25). The review of patient records was performed only for men who were operated with AR in the RT-prost group, and only those with clinically suspected AL based on the reviews were included in the study. The ISGRC definition of AL, including pelvic abscesses, was used during the review of patient records. This definition is not used by the SCRCR; moreover, AL was registered at 90 days, while the SCRCR registers AL at 30 days. This can partly explain the increase in the number of AL cases after the review of patient records, as five of the six cases of AL that were missed in the registry were minor leakages that did not require active therapeutic intervention (Grade A). A recent study per-formed in Sweden also found a considerable under-reporting of AL in the SCRCR when using the ISGRC classification of AL during journal review [30]. Another limitation of the study was the het-erogeneous type of radiation and fractioning used in the treatment of prostate cancer, as 4% of the patients received only brachyther-apy, while the majority of patients received external-beam radio-therapy with or without brachytherapy [28].
    The important questions that remain include how many of the diverted stomas became permanent and the nature of the func-tional results after stoma reversal. Unfortunately, we do not have these data. However, based on previous studies, we learned that ~19% of ileostomies performed in Sweden become permanent, often because of advanced age and co-morbidities, severe post-operative complications or advanced cancer disease [31]. In this selected group of patients who underwent AR, the individuals were healthy, had early-stage tumours and a low rate of severe compli-cations, indicating that the majority had their stomas reversed.
    The decision to perform an AR in patients who have been irra-diated previously for the treatment of prostate cancer is difficult  and a thorough discussion with the patient is warranted, together with a careful selection depending on known risk factors for anastomotic complications. A non-restorative surgery should be recommended to patients with stage IV disease, because of the high risk of AL in these individuals.