Cancer medicine: principles of treating malignant disease Part one: surgical oncology
Carlo Palmieri and Anjana Singh discuss the surgical option available in managing malignant disease
Malignant disease can be managed surgically, medically or both. Medical treatments include chemotherapy, radiotherapy, endocrine therapy, immunotherapy, and monoclonal antibodies.
Our next article will deal with the medical aspects. Here we talk about the surgical options.
Surgery plays a central role in managing malignant tumours and surgeons are often the first to see patients with symptoms and signs suggestive of malignancy. Surgical oncology has a broad remit and includes the following.
Prophylaxis
Surgery can be used to prevent cancer in patients with an inherited predisposition to certain malignancies. Examples include:
- Proctocolectomy to prevent colorectal cancer in people with familial adenomatous polyposis coli.
- Women with known genetic mutations predisposing to breast cancer--for example, BRCA1/2 mutations can benefit from prophylactic mastectomy.
Screening
This involves looking for early signs of cancer in high risk population groups and currently there are two well established screening programmes in Britain for breast and cervical cancer. In addition surgeons run clinics for those at high risk of breast cancer.
Family history and high risk clinic
Women with a strong family history of breast cancer or with known predisposing genetic mutations are regularly reviewed in these clinics.
Diagnosis
Surgeons are involved in making the initial clinical diagnosis through the process of history, examination, and special investigations, which includes tissue biopsies that can provide the essential pathological diagnosis.1
Staging
This involves investigations that include blood tests, chest radiograph, liver ultrasound, and bone scan to look for any evidence of distant metastases. This is clinical staging and these tests are usually arranged in the clinic after diagnosis.
Further staging information is provided from the operation when the primary tumour and the regional lymph nodes are removed and given to the pathologist for histological examination. This is pathological staging. Pathological staging provides important prognostic information. Examples include the TNM classification and Dukes's classification.
TNM classification system
Most staging systems are based on an assessment of the size of the tumour (T), the presence of lymph node metastases (N), and the existence of distant metastases (M).
T and N are accurately assessed by pathological staging and M is assessed
by clinical staging. TNM classification provides information about prognosis and guides further treatment decisions.
For example, in breast cancer the presence of axillary lymph node metastases is the biggest risk factor for predicting relapse and death. This directly influences decisions regarding administration of chemotherapy.
Dukes's classification
In colon cancer, the classical Dukes's classification is still referred to and has prognostic importance.
- Dukes's A: invasion of cancer into the bowel wall (no spread beyond muscle layer).
- Dukes's B: invasion through the bowel wall.
- Dukes's C: involvement of local lymph nodes.
- In practice, a modified Dukes's classification is used, which includes Duke's D--that is, presence of distant metastases and is more like the TNM classification.
Treatment
Curative
Surgery is a curative treatment for solid tumours if carried out before metastasis has occurred. Treatment ranges from a wide local excision of the cancer to the removal of the whole organ. Examples include nephrectomy for renal cell cancer and wide local excision or mastectomy for breast cancer.
Surgery can be used to treat in the metastatic setting to remove localised metastasis, which may result in cure. Examples include solitary hepatic metastasis in colorectal cancer and retroperitoneal lymph node dissection in testicular cancer.
Adjuvant therapy
Surgery has been used in the past in adjuvant setting for tumours known to be dependent on hormones for growth--that is, breast and prostate cancer. In addition, surgery has a supportive role in the delivery of adjuvant chemotherapy. Examples include oophorectomy in breast cancer or orchidectomy in prostatic cancer (now generally superseded by the development of LHRH analogues) and insertion of Hickman lines for administration of adjuvant chemotherapy.
Palliative
In this context, surgery may be used to debulk the tumour and so improve response to subsequent chemotherapy, to provide symptomatic relief, or to prevent complications due to metastatic disease. It can:
- Improve response to subsequent treatment--for example, debulking of advanced ovarian cancer.
- Relieve gastrointestinal obstruction--for example, resection of advanced gastric or colonic carcinoma or a surgical bypass procedure to relieve obstruction.
- Prevent or deal with complication due to metastatic disease--for example, orthopaedic intervention to prevent fractures or treat fracture secondary to bone metastases.
- Relieve symptoms--for example, insertion of shunts: Denver shunt for ascites and oesophageal stent to relieve dysphagia in oesophageal cancer.
Plastic and reconstructive surgery
This is used to modify and reduce the functional, cosmetic, and psychological morbidity that can occur after radical surgery to remove a tumour. Examples include breast reconstruction after mastectomy and reconstructive surgery of face after excision of oral tumours, skin cancers, and head and neck tumours.
Question:
A 52 years old woman presents with a breast lump. How would you arrive at a diagnosis?
Answer:
History. Take a history of the lump and any associated symptoms--for example, pain, nipple discharge. Secondly, take a history for risk factors--for example, family history of breast cancer, early menarche, late menopause, lack of parity and breast feeding, and use of oral contraceptive pill and/or hormone replacement therapy.
Physical examination. This would include examination of the involved breast and in particular the lump as well as the contralateral breast and the axillary lymph nodes. In addition, a general examination should be performed. A hard, irregular lump fixed to the skin or underlying muscle with distortion of the breast is likely to be a carcinoma whereas a mobile, smooth, regular lump is more likely to be benign.
Special investigations.Imaging in the form of a two view mammography of the affected and the normal breast is the next step. (Ultrasound scanning is used to investigate the premenopausal breast, which is glandular and therefore considerably denser.) As well as demonstrating the lump, imaging also allows detection of any additional impalpable lesions.
Following imaging a biopsy (FNA or core biopsy) of the lump is performed for pathological examination, which provides the definitive diagnosis.
Triple assessment is the term given to the key combination of physical examination, imaging, and biopsy in the diagnosis of a breast lump.
Definitions
Neoadjuvant: refers to any treatment given before definitive local treatment, usually surgery. Such treatment is given when complete surgical resection is not initially possible--for example, in breast cancer chemotherapy or hormonal therapy may be given before surgery. In addition, at surgery neo-adjuvant treatment can allow sparing of normal tissue with important function--for example, anal sphincter. AIM: to reduce tumour bulk and allow complete surgical resection--that is, to downstage tumour.
Adjuvant: is literally a treatment given in adjunct to another treatment modality, usually in the curative setting--for example, in colon cancer chemotherapy can be given as adjuvant treatment to surgical excision. AIM: to destroy any early, undetectable disseminated cancer cells (micrometastases) and thus improve survival or prevent local recurrence of the disease.
Curative: as the name suggests such treatments are provided with the aim of curing the disease and surgical, medical, or a combination of treatments may be used including the two types mentioned above. AIM: to cure!
Palliative: is treatment given to locally advanced or metastatic disease, which is incurable. AIM: to control and reduce tumour bulk, to relieve symptoms, and to prevent and treat tumour related complications.
Question:
What are the surgical options for this woman if her lump turns out to be a cancer?
Answer:
In general, the options are wide local excision (breast conserving surgery); quadrantectomy (removal of the affected quadrant of the breast); simple mastectomy (removal of entire breast tissue as well as skin, nipple, and areola).
The choice will depend on the size of the lump in relation to the size of the breast, the position of the lump, and whether there is any additional disease in the breast which may be multifocus--for example, ductal carcinoma in situ (DCIS). Therefore a small lump with surrounding normal tissue is amenable to treatment by WLE, while mutiple tumours, a single large tumour, or multifocus DCIS usually require a mastectomy to ensure complete clearance.
An axillary lymph node dissection is also usually performed to treat any lymph node metastases and provide prognostic information which will guide further treatment.
If a mastectomy is to be carried out the patient is usually offered an immediate or delayed reconstruction of the breast. Reconstruction of the breast can be carried out using prosthetic implants (usually either silicone or the saline filled Becker implants) and/or a muscle flap--for example, latissimus dorsi flap.
Question:
What is the role of surgery in the management of colorectal cancer?
Answer:
Surgery has a role in the prevention, diagnosis, treatment, and staging of colorectal cancer.
Prevention. This includes prophylactic proctocolectomy in patients with familial adenomatous polyposis coli and the screening of other patients with a strong family history using faecal occult blood samples and colonoscopy.
Diagnosis. This involves reviewing patients with suspicious symptoms in clinic where an examination that includes digital examination of the rectum, proctoscopy and rigid sigmoidoscopy, and investigations in the form of blood tests are carried out. A colonoscopy may be arranged. Biopsies of any suspicious lesions can be taken at proctoscopy, sigmoidoscopy, or colonoscopy.
Treatment and staging.This involves removal of the tumour and a margin of normal bowel. At laparotomy, the liver is also inspected to exclude any obvious metastatic disease. This is performed in addition to liver ultrasound. If the tumour is unresectable and is causing obstructive symptoms, a bypass procedure may be performed. In addition, surgery can be used to insert a Hickman line for the administration of chemotherapy.
The resected colon along with pericolic and mesenteric lymph nodes are reviewed by a histopathologist who will note, among other things, how far the tumour has invaded through the bowel wall and if the lymph nodes contain metastatic disease (Dukes's classification).
Carlo Palmieri, CRC clinical research fellow, and Anjana Singh, surgical research fellow, Department of Cancer Medicine, Imperial College School of Medicine, London
Email: c.palmieri@ic.ac.uk
studentBMJ 2001;09:305-356 September ISSN 0966-6494
- Palmieri C, Singh A. Cancer medicine. studentBMJ 2001;9:137-8. (April 2001..)
