PERCEPCIONES SOBRE LA PRÁCTICA DE CUMPLIMIENTO DE

Accepting that Nd YAG laser presently offers an excellent treatment for palliation of oesophageal cancer we set out to assess the effect of additional external beam radiotherapy. There is a sound theoretical basis for the combination as outlined in chapter 2. However there very litde data available on the combination of laser and radiotherapy prior to these studies. A pilot study was performed initially in order to determine an appropriate radiotherapy dose regime, to assess if the combination treatment was promising and if so to provide data to allow us to estimate adequate numbers for a randomised study. The results of the pilot study were encouraging both in terms of reduced number of therapeutic procedures and possibly improved survival. The problem with a pilot study of this nature is that patients with better prognostic factors tend to be selected. Although these patients required markedly less frequent endoscopic procedures than historical controls treated with laser alone this may have been partly because the populations were different in the first place and not solely due to differences in treatment.

The subsequent randomised study confirmed that the period between therapeutic endoscopic procedures required to control dysphagia was prolonged in patients receiving external beam radiotherapy. The difference is not as great as the pilot study had suggested. The periods between therapeutic procedures required after 'check’ endoscopy were increased to 9 weeks from 5 weeks which may be a useful benefit for some patients, particularly the minority who find endoscopic procedures very unpleasant or who have to travel long distances for treatment. There was however no difference in survival between those treated with laser only and laser with external beam radiotherapy. This is an important finding and casts doubt on

the practice of giving external beam radiotherapy in the doses used to patients who are intubated for palliation of oesophageal cancer (Oliver 1990). A prolonged survival is the only conceivable benefit for such patients.

The use of endoluminal ultrasound in assessing tumour extent was useful. We demonstrated that external beam radiotherapy was probably having some effect on malignant nodes but the effect was not as great as that with chemotherapy. A reduction in node size in around 50% of similar cases treated with new chemotherapy regimes and monitored with CT scanning has been recorded (Mason 1992). Our results also showed that patients with bulky tumours or large involved nodes on endoluminal ultrasound have a poor prognosis and benefit little from this approach. Defining such patients who would not benefit from external beam radiotherapy is as important as defining those who will. To spare such patients the extra hospitalisation required for radiotherapy which encroaches on a limited prognosis is important.

We did not assess quality of life prior to laser. However the previous studies discussed do demonstrate quite an impressive improvement in scores after successful laser recanalisation. The quality of life assessments performed demonstrated a transitory fall during external beam radiotherapy. Overall there is no apparent long term difference between the two groups. It is reassuring that the more formal testing used correlates quite well with our own subjective impression of treatment outcome.

The positive correlation between the quality of life assessments used and quality of swallowing is highly significant but not strong. Overall only 18% of the variability in the QL index can be accounted for by the dysphagia grades recorded. This demonstrates that there are many other factors relevant to the quality of life. Such factors however may well be related to inexorable tumour growth and associated

symptoms may be more difficult to control. Many patients who find their diagnosis difficult to accept may suffer an impaired quality of life purely due to the diagnosis of cancer. Dysphagia is however a symptom that can be directly addressed and relieving this troublesome symptom will improve quality of life irrespective of other factors. For maximum clinical benefit concentrating our efforts on attaining the best possible swallowing is therefore appropriate.

In future studies it would be interesting to correlate other factors with quality of life scores to determine more clearly which are important. One such factor often not directly assessed is nutrition. A period of a few weeks enteral nutrition either by nasogastric feeding tube or percutaneous endoscopic gastrostomy (PEG) after initial referral for palliation may improve quality of life.

It is also possible that frequent visits to hospital for laser treatment are beneficial as the care and attention provided by Nursing and Medical staff may lift the patients morale enough to improve quality of life scores. This would be more difficult to test in the clinical setting.

The cost data demonstrates a significant extra cost of £1150 for patients receiving radiotherapy. Overall the limited benefit from external beam radiotherapy is disappointing and the significant extra cost is difficult to justify. The finding that external beam radiotherapy is having some effect on the tumour is however important. It may be possible to improve on the radiotherapy effect with simpler and cheaper regimes.

Local radiotherapy (Brachytherapy) is becoming more practicable as more units have equipment such as the 'Selectron' which can deliver high dose rate sources to the relevant organ. Prior to this development such local treatment with a low dose rate source would have taken 2-3 days but can now be applied in 10 minutes. The

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operator only has to pass a nasogastric tube and programme the machine to deliver the dose required (usually lOGy at a distance of 1 cm from the source) at the appropriate area. This approach delivers a high dose to the tumour but the dose rapidly falls off with distance from the source. Thus systemic effects should be minimal. There is however some doubt that large nodes will be adequately treated as they may be several centimetres from the source. This problem may be partly addressed by a second treatment after a few weeks.

Day case treatment with Brachytherapy costs no more than the equivalent of 2 or 3 days hospitalisation. If it is as effective as external beam treatment in reducing the necessity for further endoscopies the cost saving on follow up procedures equal the costs of brachytherapy. Early data from our unit in 15 patients with adenocarcinomas of the cardia (Spencer 1994) indicates that this approach may be more effective than external beam radiotherapy and further work is justified. Other promising approaches include shorter external beam radiotherapy regimes (Bleehan

1991) or combination of external beam radiotherapy and brachytherapy (Agrawal 1992).