2017 Section 7 Green Book

B. Sethugavalar et al. / Oral Oncology 59 (2016) 80–85

Chen et al. [22] reported an increased risk of late oesophageal strictures requiring dilatation (30% versus 6% for the prophylactic versus reactive approach). A recent retrospective study reported a 5-year incidence of severe late dysphagia in 30.8% of the reactive NG tube cohort ( n = 36), and 60.9% in the prophylactic PEG cohort ( n = 25) with a PEG being associated with an increased rate of sev- ere late dysphagia on a multivariate analysis [21] ; however, the prophylactic PEG cohort were a historically earlier cohort prior to a shift in the institutional approach to enteral feeding. Mekhail et al. reported a 30% versus 8% dysphagia rate at the relatively early time point of 6 months post treatment for gastrostomy versus NG feeding [30] . In a prospective study Corry [31] similarly found an increase in grade 3 dysphagia with the use of a gastrostomy (25% versus 8%) at the same 6 month timepoint post-treatment. Oozeer et al. [32] used patient-reported swallow outcomes obtained using the validated MD Anderson Dysphagia Inventory (MDADI) ques- tionnaire to perform a matched pair analysis in a group of 31 patients who completed the questionnaire at least 2 years post- treatment; the MDADI scores for all domains were significantly superior for the reactive NG group compared with the prophylactic gastrostomy group. By contrast, one prospective randomised study [18] reported that the prophylactic PEG group had a lower rate of long term grade 3 dysphagia (3% versus 9%) and a higher propor- tion of patients who resumed a normal diet (93% versus 80%) [18] . Recent systematic reviews have reported that the impact of prophylactic PEG use on swallowing and swallow-related out- comes remains unclear and an area of clinical equipoise [33,34] . This remains an area of controversy and wide variation in practice [10] . An ongoing randomised trial [35] may prove to be informative if recruitment can be successfully completed, although previous randomised studies have failed to complete recruitment [36] . We have previously reported long term patient-reported swal- low outcomes in a cohort of patients treated in the era of 3D- conformal radiotherapy [1] . However, advances in radiotherapy techniques may impact upon swallow function, and conclusions from studies performed in the 3D-conformal radiotherapy era are not necessarily applicable to the IMRT era. Advances such as the introduction of parotid sparing IMRT have reduced xerostomia [37] and may benefit swallow function; by contrast, the move from 3D-conformal radiotherapy with a matched anterior neck field with midline shielding to whole field IMRT has led to an increase in the midline neck dose, including the larynx and pharyngo- oesophageal axis. The impact of this remains unclear, with an uncertain dose response for swallow dysfunction. An alternative technique is matching IMRT with a neck field, and it remains unclear whether this has a favourable impact upon swallow func- tion compared with whole field IMRT [2] . There is currently inter- est in developing ‘swallow-sparing’ IMRT, although at present the efficacy of this approach remains uncertain [2] . Assessment of swallow outcomes is complex, with multiple potential tools, including physician assessed toxicity scores, patient reported function, and physical outcomes including stric- ture rates [2] . Patient and clinician reported outcomes may both be valuable, although it is recognised that clinicians may underes- timate dysphagia compared with patients [38] . The MDADI is a val- idated tool for assessing patient reported swallowing outcomes [25] . In addition to the method of swallow assessment, the timing is likely to be a critical factor influencing outcome. For example MDADI scores have been found to significantly improve at 12 months post treatment when compared with earlier timepoints [4] . These data suggest that swallow function is continuing to improve 12 months post-treatment and may have yet to plateau. This is consistent with the observation that salivary recovery does not plateau until two years post treatment [37] . This study has addressed the important clinical question of whether the use of a prophylactic gastrostomy or a reactive NG

Table 2 MDADI scores according to intended enteral feeding route.

Prophylactic gastrostomy ( N = 26)

NG as needed ( N = 26)

p -value

0.04 0.04 0.38

Total: Mean (SD) Global: Mean (SD) Physical: Mean (SD) Emotional: Mean (SD) Functional: Mean (SD)

59.4 (16.8) 60 (26.5) 57.1 (14.9) 60.4 (19.1) 61.7 (20.1)

68.1 (12.9) 67.7 (24.7) 59.6 (11.4) 73.5 (15.1) 75.4 (15.5)

<0.01 <0.01

Values which are statistically significant are shown in bold.

Table 3 Univariate analysis of predictors of MDADI score.

Factor

p -value Total Global Physical Emotional Functional

Age

0.34 0.78 0.5 0.71 0.83 0.74 0.11 0.42 0.06 0.37 0.39 0.52 0.11 0.45 0.33

0.53 0.52 0.09 0.44 0.16

0.22 0.68 0.16 0.26 0.05 0.11 0.30 0.03 0.06

T stage N stage

Induction chemo

No. induction chemo cycles

Conc chemo type

0.1 0.15 0.08

0.06 0.18

No. conc chemo cycles 0.19 0.84 0.27

0.02

<0.01 0.02

Pre-treatment diet Mean contralateral parotid dose

0.16

0.16 0.46 0.60

0.07

Values which are statistically significant are shown in bold.

age, sex, smoking status and baseline diet. There was a non- significant difference in the number of patients who received induction chemotherapy between the two groups, although the total number of cycles of concurrent chemotherapy delivered was similar. The difference in mean contralateral parotid dose between the two groups was not significant. Patient-reported swallowing function measured using the MDADI was superior for patients managed with an NG tube as required compared with a prophylactic gastrostomy: overall com- posite score 68.1 versus 59.4 ( p = 0.04), global score 67.7 versus 60 ( p = 0.04), emotional subscale 73.5 versus 60.4 ( p < 0.01), func- tional subscale 75.4 versus 61.7 ( p < 0.01), and physical subscale 59.6 versus 57.1 ( p = 0.38). The composite total, global and domain-specific (physical, emotional and functional) subscales for each group are detailed in Table 2 . Each domain is scored 0– 100 with higher scores indicating better swallow function. A uni- variate analysis was performed to explore the relationship between patient, tumour and treatment factors with MDADI scores ( Table 3 ). Age, T stage, N stage, and treatment factors including use of induction chemotherapy, number of concurrent chemotherapy cycles and mean contralateral parotid dose, did not correlate with MDADI scores in any domain. By contrast, the quality of pre- treatment diet according to a simple scale of consistency was found to be significantly associated with all domains of the MDADI other than the global subscale. This was confirmed on a multivari- ate analysis, with only having a more normal pre-treatment oral intake was significantly associated with higher MDADI emotional ( p = 0.02), physical ( p = 0.01), total ( p = 0.02) and possibly func- tional ( p = 0.06) scores.

Discussion

Long term swallow function is a major survivorship issue [4] . There have been conflicting reports regarding whether the use of a prophylactic gastrostomy may have a detrimental impact upon long term swallow function compared with a reactive approach.

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