Provided by Dr. R P Beaney of St Thomas’ Hospital, London
Exenterative surgery is a major complex procedure for the en masse excision of most of the pelvic viscera. It is sometimes used in stage 1Va disease where the cancer has spread from the cervix or uterus to involve the bladder or bowel without more distant spread of disease. In this scenario the intent is to cure the patient. That is disease confined to the pelvis where further radiation therapy or chemotherapy is deemed inappropriate. This is usually done in an attempt to cure the patient but in rare situations may be performed to palliate distressing symptoms - e.g. fistulae.
The operation consists of a hysterectomy, pelvic lymph node dissection and removal of bladder (anterior exenteration), rectosigmoid colon (posterior exenteration) or both (total exenteration).
In the case of an anterior exenteration a segment of Ileum or sigmoid is used as a urinary diversion conduit to allow the urine to drain into an externally worn bag. Sometimes transverse colon is used if the patient has been previously irradiated. The bowel needs to empty into a bag.
In the case of a posterior exenteration faecal diversion is required in the form of a colostomy where the bowel contents empty into an externally worn bag.
In the case of a total exenteration then both diversions are required.
Historically a gynaecologist, urologist, bowel surgeon and plastic surgeon had to be available at the same time. More recently the specially trained gynaecological oncologist simply works with a plastic surgeon. Post-operative care has to be of the highest quality.
5 year survival rates are in the region 30% in those whom exenteration was completed. In the SE Thames region around 20 patients are deemed suitable each year.
Specialised Services for Cancer: Non-tumour Specific
A7 Brachytherapy
Provided by Dr. Heather Payne of University College Hospital, London
Brachytherapy or ‘short distance’ therapy is a term that is used to describe radiotherapy treatment in which a radiation source is placed within or close to the tumour. This contrasts with external beam therapy or teletherapy where the radiation focus is usually at a distance of 80-100cms from the patient.
The advantage of brachytherapy is that the radiation source gives a very high dose to the tumour but this dose decreases rapidly with increasing distance from the source and therefore has very little effect on the surrounding normal tissues.
Brachytherapy procedures can be performed with a variety of radiation sources; these radio-isotopes include irridium, iodine, gold and caesium. They can be made in several forms such as needles, seeds and ribbons.
Brachytherapy treatments can involve temporary or permanent implants. One example of a permanent implant is the insertion of low dose rate iodine seeds into the prostate.
Temporary implants involve the insertion of catheters or hollow applicators into the tumour. The radioactive sources are then inserted into these applicators and left in position to give the desired dose of radiation. At the end of the treatment time the sources and the applicators are removed.
Because this treatment approach involves radioactive sources, certain precautions must be undertaken to avoid unnecessary exposure of personnel and family members to radiation. Most temporary brachytherapy is now given with a remote control ‘after loading’ system. Gynaecological tumours such as carcinoma of the cervix and uterus are conventionally given a radiation boost using this approach after external beam radiotherapy. There are other new applications for temporary brachytherapy treatments and these include cancers of the prostate, bronchus and oesophagus; techniques for the treatment of other sites are being developed.
A8 Hyperthermia
Provided by Dr Clare Vernon of Hammersmith Hospital, London
Hyperthermia is used in the treatment of cancers as a means of sensitizing tumours to the effects of radiotherapy or chemotherapy. It is usually used for superficial tumours - e.g. breast or melanomas, or more deep-seated tumours - e.g. cervix, rectum or bladder, but whole body, interstitial or limb perfusion is also possible. The usual aim is to deliver 60 minutes of heat at 43 degrees centigrade, once per week, in combination with a fractionated course of radiotherapy or during a chemotherapy infusion. It is delivered using microwaves, ultrasound or radiofrequency.
Treatment involves the insertion of small probes under local anaesthetic into the tumourous area to monitor temperatures and is usually well tolerated by patients. Superficial hyperthermia is relatively simple to delivery, but regional or whole body treatments require more complicated equipment and a multi-disciplinary team approach. When given by skilled personnel, the side-effects are no greater than with standard therapies.
There are now over 30 randomised phase III trials demonstrating the clinical effectiveness of the addition of hyperthermia with response rates in the order of 40% for the standard arm and 60% for the combined modality treatments. The majority of these trials have involved hyperthermia and radiotherapy, and have concentrated on local control, but a recently published trial from Holland, where it is now recommended treatment, have shown a survival advantage for the addition of hyperthermia in the treatment of cervical cancers. Economic evaluation has shown hyperthermia to be a cost-effective treatment.
Facilities for treatment with hyperthermia in the UK are very limited, and there are many patients who could benefit from it, to whom it is not available. It is in much more widespread use in the USA, Europe and Asia
A9 Radionuclide Therapy
author required
A10 Specialised Palliative Services for Common Cancers
author required
A11 Photodynamic Therapy (PDT)
Provided by Professor S G Bown of the Middlesex Hospital, London
Photodynamic therapy (PDT) is a new technique for destroying small areas of malignant tissue. In many ways it is like radiotherapy, as the same treatment can be applied to diseases in many different organs, although the effect is much more localised. However, PDT has the major advantage that it does not cause the same long term effects as radiotherapy, so can be repeated multiple times at the same site, if necessary, which radiotherapy cannot. Further, the biological effect is relatively gentle as connective tissue (the “scaffolding” that holds tissue together) is largely unaffected, so treated areas in solid and hollow organs heal with excellent cosmetic and functional results. Small cancers on the skin and in the mouth can heal so well after PDT that it may be difficult to see where the original lesion was. It is effective for small cancers of hollow organs like the oesophagus, stomach and lungs that have not spread beyond their site of origin, although in the current stage of development, is only used in patients with very early cancers who are unsuitable for conventional surgery.
PDT involves giving the patient a special drug (usually by injection) which sensitises the body to light and then activating the drug in the diseased area with red light, most conveniently delivered from a laser using flexible optical fibres. As the drug has no effect in the absence of light, the effect can be localised to the area where the laser light is applied (although care has to be taken as drug in the skin may be activated by ambient light). Normal as well as diseased tissues can be affected, but this is rarely a problem as the normal areas heal so well.
The red light used for PDT only penetrates a few mm into tissue, so the depth of effect at each treatment site is small, typically less than 1cm. However, by employing ingenious light delivery systems, often with several fibres inserted through needles, which have been passed through the skin into tumours of internal organs, it is becoming possible to treat a range of internal cancers such as of the prostate and pancreas. Another promising indication is the treatment of pre-cancerous changes in hollow organs like the gastrointestinal tract and major airways as the superficial layer of the tissue (the mucosa, where the pre-cancerous changes arise) can be destroyed without damaging the underlying layers, such as muscle.
The real attraction of PDT in cancer therapy is the nature of the biological effect. It is gentle, the effects usually heal extremely well and it can be applied when other treatments like radiotherapy and surgery have failed. Increasingly, it is showing promise as the treatment of first choice for pre-cancerous conditions and for small cancers in areas where the cosmetic and functional result is particularly important (as on the skin or in the mouth). For the future, it has potential for localised cancers where surgery is not technically feasible or which are known to respond poorly to radiotherapy and chemotherapy.
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