Kamis, 12 Maret 2009

Gyn --onko

Basic Principles in
Gynecology Oncology Surgery

Obstetrics and Gynecology Department University of Gadjah Mada/Sardjito Hospital Yogyakarta

Back Ground
Surgery is the mainstay of treatment for most patients with solid tumours. Surgery is most effective when cancer is localized, and substantial number of long term survivors can be achieved with some tumors types that show metastatic disease at presentation.
Surgery has the three main roles in the management of cancer patients :
- diagnosis and staging
- curative
- palliative
The goal of the lecture is understanding towards the roles of surgery in the management of gynecologic cancers.

Tumor behaviour
An understanding of tumour biology is essential to the planning of surgical treatment for cancer.
The behaviour of solid tumors is diverse and the implications for surgery are often paradoxical. The three principal methods of spread are :
- Direct infiltration
- Lymphatic
- Blood borne
Most cancers disseminate by all three methods, although one method of spread maybe predominant. Breast and colorectal cancer exhibit both blood and lymphatic spread. Cervical cancer and ovarian cancer exhibit predominantly by direct infiltration to nearby organs. Even cancers arising from the same cell type behave differently – papillary and follicular tumours of the thyroid give rise to lymphatic and haematogeneous metastases respectively. Different surgical approaches will be required depending on tumour type.
Surgery is often more successful in the treatment of cancers with haematogenous spread compared to those with more developed local and lymphatic metastases.
Growth rates of cancers vary enormously. Patients with breast cancer may relapse many years after primary treatment while those with upper gastrointestinal tumours usually die within two years of diagnosis. There are real differences in growth rate. Endocrine related cancers often have very slow growth rates and metastases may appear years after initial resection. Repeated excision of metastatic disease may lead to long term survival in such tumours but this approach would be futile for gastric and oesophageal cancer.

The development of cross sectional radiology, ultrasound, CT, and MRI – together with radiologist’s ability to perform core biopsies or fine needle aspiration cytology combined with use of endoscopy and biopsies or cytological brushing, allows pre-operative diagnosis to be made in most cases.
A significant advance in reducing unnecessary suffering for patients has been the use of these procedures to stage accurately cancers prior to surgery. This has been most important where surgical treatment carries significant morbidity and mortality, such as in major resection ot the stomach or oesophagus. But such procedures would not be appropriate for diagnosis and staging of ovarian cancer and endometrial cancer. The staging of both those gynecologic cancers should be based on surgery. At the same time, we could do both staging and curative surgery.
The approach should be to establish a histological diagnosis by endoscopic biopsy with radiological staging, using a combination of endoscopic ultrasound, cT, or MRI. Laparascopy, has been used instead of laparatomy to detect small peritoneal or liver metastases and is helpful in determining fixation. Using these methods, we could reduce ‘open and close’laparatomies for unresectable cancer by <5%, avoiding unnecessary surgery for patients at a disease’s terminal stage.

The long term outcome after cancer surgery depends on tumour type, tumour differentiation (well, moderate or low differentiation), spreading of the tumour to lymphatic vessels/nodes or blood vessels and the stage at presentation.
Survival rates for some cancers have improved due to earlier presentation following public awareness and screening programmes e.g. pap smear for cervical cancer screening.
Long term tumour control can only be expected if all the cancer is removed at the operation. Such operations would be beneficial for ovarian cancer. In fact, the operation for ovarian cancer considered adequate if we could removed most of the tumor (only < 1 cm of tumour tissue is left).
Conservation surgery is important approach for gynecology cancer patients who are still in childbearing age, We should carefully select patients to whom we could do conservation surgery.
With the development of high quality radiological imaging and more accurate staging, more localized, low morbidity operations can be performed.

Palliative surgery
Surgical palliation falls into several different categories, requiring a broad range of expertise and knowledge. A patient’s life expectancy may vary from weeks to years depending on their condition, and the surgeon must know when not to operate and to utilize palliative care teams and interventional radiology, as well as to decide when and what operation is required.

Bowel obstruction
Patients with colon or ovarian cancer make up the bulk of those developing small or large bowel obstruction. In colon cancer patients, confirmation of incurability will usually made at laparatomy, following a decision to treat a large bowel obstruction. Where possible, these patients should have the primary anastomosis. Management of the obstructed ovarian cancer patient is usually more difficult as the key decision is often whether or not the patient should have the operation.
Many patients will have multiple obstruction sites, with their small and large bowel studded with tumours on the serosal surface. Such patients are not suitable for surgical palliation. Others will have 1 or 2 sites of obstructions e.g. a segment of terminal ileum embedded in pelvic tumours. They can benefit from debulking, resection and anastomosis or bypass surgery.
Differentiating these categories of patient can usually be done by a history of crampy abdominal pain, clinical examination revealing a distended tympanitic abdomen (as opposed to an adomen with multiple sites of palpable tumours and ascites), plain x rays revealing many loops of distended bowel with air fluid levels and CT evidence of pelvic or other single site tumour deposit.
Laparascopy will sometimes be helpful in the obstructed patient who has not had previous abdominal surgery.

Fistulas caused by pelvic tumours or post radiotherapy include
§ rectovaginal
§ enterovaginal
§ colovesical
§ vesicovaginal
§ combination of above
A proximal end sigmoid colostomy is the treatment of choice for most rectovaginal fistulas. Patients with combined rectovaginal and vesicovaginal vistula may need an end colostomy and ileal conduit. A covered stent, delivered endoscopically or at x ray, should be considered for patients with a colovesical fistula. Patients with an enterovesical fistula will require laparatomy resection of small bowel segment and anastomosis.

Ascites has become the major complication for ovarian cancer patients. Peritoneal venous (Leveen) shunts can be inserted to relieve ascites in selected cases. Careful preoperative assessment should be undertaken to ensure that ascites is not loculated and that the tumour is not mucinous, otherwise the shunt will become blocked. These are usally inserted using local anaesthetic and sedation, with >50% of patients achieving long term palliation.

There are a number of options open to oncological surgeons to help patients with pain :
§ Surgical debulkinb of large slow growing tumours (e.g. intraabdominal, soft tissue sarcomas in otherwise fit patients where expected morbidity is low)
§ Stabilization of pathological fractures and bone metastases involving > 50% of cortex
§ Neurosurgical approaches for pain control including cordotomy

Gastrointestinal bleeding
A wide array of endoscopic and radiological techniques are available to stop bleeding from benign and malignant causes in incurable cancer patients, including injection sclerotherapy (benign ulceration), laser coagulation (neoplastic ulcers), and radiological embolization. Surgery should be reserved for those with a life expectancy of 3 months or more for whom these methodes fail.

Palliative resection of the primary tumours
Resection of primary tumor to achieve locoregional control may improve patients quality of life, preventing fungation or uncontrolled axillary metastases. In those in whom unresectable liver metastases are identified, primary tumours resection should still be considered to minimize the risk of bleeding, perforation, or obstruction, which may subsequently occur.

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