Is there more than one late radiation proctitis syndrome?
Introduction
Curative irradiation for prostate cancer is assuming an increasing workload within most Australasian radiotherapy centres. Crude late rectal toxicity rates following treatment have varied from as low as 2% to as high as 30% depending on the toxicity level considered significant and the method of calculation [21], [35]. The increasing clinical prevalence of late proctitis underlines the importance of investigating the problem thoroughly. Several groups have addressed this question as part of more global studies of quality of life in patients treated for prostate cancer but no attempt has been made to unravel the spectrum of symptoms making up the disorder [4], [5], [14], [17], [34], [36], [41]. The complete characterisation of late sequelae is also necessary to justify radiotherapeutic intervention for early stage disease.
The constellation of symptoms contributing to late proctitis was alluded to as long as 15 years ago and the RTOG defined proctitis as ‘being characterised by rectal irritation or urgency (tenesmus), presence of mucous or blood in the stool and, in some patients frequent loose bowel actions’ [27]. Since then [25] the EORTC/RTOG scoring system or the occurrence of rectal bleeding has often been used to estimate the incidence of late proctitis and factors that influence it [1], [3], [12], [13], [25], [26], [27], [29], [30], [31], [32]. More recently, the LENT/SOMA scoring system for late radiation injuries has been introduced which lists six different symptoms for proctitis [15], [23], [28]. It is commonly observed, but infrequently reported, that different symptom patterns are exhibited by patients suffering chronic proctitis. In some cases bleeding is the dominant symptom, in others frequency and urgency predominate. In this prospective study we recalled patients treated for prostate cancer over a 7-year period to see whether different symptom permutations do exist and secondly to assess the factors that contribute to these symptoms. Further aims were to assess the utility of the EORTC/RTOG late scoring system and to look at how the symptoms that contribute may impact on the patient's day-to-day life.
Section snippets
Overview
After obtaining local ethics committee approval, all surviving patients treated for prostate cancer with conventional external beam radiotherapy between 1987 and 1994 at our institution were recalled to enable a detailed prospective assessment. This included a group of 64 patients previously studied for their hair cortical cell in vitro radiosensitivity during prostate irradiation [11]. All 284 patients who responded to the recall invitation had their treatment planned using CT and carried out
Analytical methodology
To determine whether different rectal symptom patterns exist within the study population a technique known as K-means clustering analysis (Statistica, Statsoft, Tulsa) was employed. In this process the six most common rectal symptoms graded by each patient (according to the grading scales presented in Table 2) have been examined to establish whether these symptoms are randomly distributed amongst the study group. K-means clustering is an iterative technique where the program starts with k
Results
A total of 244 patients with a median follow up of 2.9 years (range 1.3–9.0) responded to the invitation to recall assessment representing an 86% response rate. The median age of these patients was 73 years at the time of treatment and the stage breakdown and various technical treatment parameters are summarised in Table 3.
Discussion
Although late radiation effects in this study were assessed in detail in a prospective and systematic way a number of limitations need to be acknowledged. It is important to note that the sample population can not be regarded as representative of the entire population of patients treated. Firstly, of course, only living patients were available for recall. Secondly, even although 86% of our patients responded to the recall invitation, it is likely that the patients who respond to a recall study
Conclusions
There may be more than one late (chronic) radiation proctitis syndrome, which may be linked, in greater or lesser degrees with symptoms of acute proctitis that occur during treatment. Faecal urgency is a common late symptom which often has an important impact on normal daily life and which deserves recognition in late normal tissue scoring systems. Confirmatory and explanatory studies are necessary.
Acknowledgements
We thank Joelle Bear for assistance in compiling the data, Keith Dear for statistical advice and Deborah Wright for preparing the manuscript. Dr Jorgen Johansen was supported by the Danish Medical Research Council.
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