Oxford American handbook of oncology. Second Edition. Oxford University Press (2015)
For some tumor types (such as colorectal cancer, renal cell carcinoma, or sarcoma), patients with a single site or limited number of metastases may be considered for resection. Resection of the so-called oligometastatic disease is most commonly performed when the liver or lung are involved.
The diagnosis of metastatic disease may be recognized either synchronously or metachronously with the primary tumor. Some patients with limited secondary deposits in lung, liver, or brain may have prolonged survival, but the patients should be carefully assessed at a multidisciplinary team meeting to consider fitness for major surgery, likely benefit, potential complications, and patient and family wishes.
Indications for metastasectomy of the lung or liver include the following:
- The primary tumor is controlled (or controllable).
- There is no other evidence of metastatic disease.
- The metastases are completely resectable, allowing enough normal tissue for normal organ function.
- There is no medical therapy that would be superior to surgery.
For patients with liver metastases that are not surgical candidates, other therapies may be used:
- Radiofrequency ablation
- Injection of alcohol
Presentation usually is that of a pathological fracture. Breast and prostate are the most common primary sites followed by lung, thyroid, and renal cancer. Mean survival is 3 months for lung cancer to over 2 years for breast cancer.
- Investigations: MRI and PET scanning are the most accurate investigations, followed by bone scanning.
Internal fixation is useful if:
- There is weight-bearing bone, especially if a lesion is >2.5 cm or involves circumference
- Painful secondary after radiotherapy
- It will improve mobilization and nursing care
- Patient is fit
- Bone quality will support fixation
Considerations in spinal secondary:
- Stability of spine
- Spinal cord compression
- Treatment options
- Hormone manipulation
- Surgery: stabilization preceded by bone tumor biopsy (occasionally it is possible to excise the secondary deposit)
- Internal fixation techniques include plates, intramedullary nails, and prosthetic replacement of metaphyseal lesions.
- Occasionally cast or brace immobilization or external fixation is used for patients with extensive localized disease that cannot be immobilized by internal methods. Rarely is amputation appropriate, except for fungating tumors, recurrent infections, and intractable pain.
- Minimally invasive treatment of metastatic bone lesions with radiographically guided percutaneous injection of bone cement is currently used in selected cases, for example, in the spine.
- Common: Up to 10% of cancer patients have brain secondaries.
- The 5-year cumulative incidence of brain metastases is 16%, 10%, 7%, 5%, and 1% for patients with lung cancer, renal cell cancer, melanoma, breast cancer, and colorectal cancer, respectively. Lung and breast are the most common primary sites.
- Blood-borne: The distribution of brain metastases reflects blood flow—80% of lesions are found in the cerebrum, 15% in the cerebellum, and 5% in the brainstem.
- Presentations include headache, focal weakness, altered mental status, and epilepsy.
- Hemorrhage within brain metastases may cause an acute neurological state.
- Diagnosis is by CT or MRI (the latter picks up smaller secondaries).
- Mean survival without therapy is 2 months, 3 months with steroid therapy, and 6 months with radiotherapy.
- Surgery is useful to confirm diagnosis, relieve pressure effects, and improve local control and survival.
- Survival is poor in patients with systemic uncontrolled disease, poor general medical condition, tumors lying infratentorially, poor neurological status, and a short interval from the diagnosis of the primary tumor to the diagnosis of the brain metastases.
- Tumor deposits in the thalamus, brainstem, and basal ganglia are usually irresectable because of the associated morbidity and mortality.
- Resection of a single secondary can lead to prolonged survival (melanoma 7 months, lung cancer .2 months, renal cell cancer 10 months, breast cancer 1 year, and colon cancer 9 months).
Occasionally, resection of multiple metastases is worthwhile:
- Good palliation
- Occasionally curative
- Postoperative radiotherapy helps
- Anatomical site is important
Malignant pleural effusion
Management may include thoracentesis, tube thoracostomy with or without pleurodesis, thoracoscopic drainage with pleurodesis, or placement of an indwelling pleural catheter.
Chemical pleurodesis may be performed with talc, bleomycin, or doxycycline. Talc is considered the most cost-effective agent, but side effects such as fever and malaise may limit its use in some patients. Rarely, talc may induce an adult respiratory distress syndrome (AR DS)-like syndrome.
Pleurectomy and decortication may be performed in selected patients with malignant mesothelioma.
Malignant pericardial effusion
In patients with a history of cancer, the development of a pericardial effusion is usually related to metastases, although it may be related to the treatment itself.
Except in patients in whom treatment of the primary tumor would be expected to improve the effusion, such as some patients with lymphoma, small cell lung cancer, and breast cancer, pericardial effusions are managed with surgical procedures.
Although pericardiocentesis may be effective, the recurrence rate is high and most patients with malignant pericardial effusion are managed with a pericardial window. A surgical pericardial window may be performed using a subxiphoid or thoracoscopic approach, with equivalent efficacy.
Although most patients with malignant ascites can be treated medically, peritoneal-venous shunting (Denver shunt) or the use of an indwelling catheter (Pleurx) may be useful in those with a reasonable life expectancy. Shunt occlusion and coagulopathy are limiting factors.