Introduction

Cancer is a global healthcare problem. In the year 2000, cancer accounted for 12% of approximately 56 million deaths worldwide from all causes. It is estimated by 2050 more than 27 million cancer cases per year will be diagnosed and result in 17.5 million deaths. In the UK, 1 in 3 adults will develop some form of cancer during their lifetime and 1 in 4 die from cancer.

A suspicion of cancer or diagnosis of cancer is the beginning of a difficult journey. In many ways it is like climbing a mountain for the first time; a journey filled with uncertainty and challenges which carries no guarantees (Figure 1.1). Patients often carry additional anxieties if there have been perceived delays so that a knowledge of warning signs of cancer and an understanding of referral and treatment is essential for any healthcare professional.

Figure 1.1 The diagnosis of cancer can be a lonely and challenging experience.

Patients presenting to their primary care physician with warning signs of cancer (Box 1.1) should be referred to a specialist centre for an urgent evaluation. In the UK and many parts of the World, cancer treatment is organized around a multidisciplinary team which consists of physicians, surgeons, cancer specialists, radiologists, pathologists and clinical nurse specialists. Many investigations for suspected cancer are done either in ‘one-stop’ (e.g. for breast cancer) or ‘two-stop’ clinics (e.g. lung cancer) to expedite diagnosis and treatment.

Investigations for a suspected cancer

Initial investigations are to establish a histological diagnosis of cancer, to assess the extent of local disease, and to look for metastatic disease. Further investigations are done to evaluate suitability for standard or trial treatment and to assess the severity of any co-morbid medical conditions.

Diagnostic investigations

Diagnostic investigations are undertaken in a logical order, with blood tests including relevant tumour markers and simple imaging, and proceed to the diagnostic imaging of choice for particular tumour types. Imaging helps to determine local and distant metastatic staging. Confirmation of the diagnosis can be obtained by cytology or biopsy. Many tumours require biopsy for further characterization and immunohistochemical assessment. Biopsies can be obtained by core biopsies, and guided biopsies using imaging or endoscopic visualization (Figure 1.2). All patients need a definite histological diagnosis if specific cancer treatment is contemplated. Rarely, treatment can be undertaken when the radiological appearance and tumour markers are typical (e.g. choriocarcinoma, germ cell tumours).

Figure 1.2 CT guided biopsy from vertebral body.

Staging investigations

Once the histological diagnosis is established, further investigations are undertaken to stage the cancer. The choice of investigation depends on the primary and pattern of metastasis. For example, the common sites of metastasis in lung cancer are regional lymph nodes, adrenals and liver; hence all patients with a lung cancer have CT scan of chest and abdomen (Figure 1.3). All patients who are planned to undergo curative treatment, particularly an extensive surgical resection, need additional investigations to assess their suitability for radical treatment. Functional imaging is more sensitive than anatomical imaging in detecting distant metastasis (e.g. PET scan staging alters conventional staging in up to 25% of patients). Endoscopic ultrasound and thoracoscopy and laparoscopy are also used in staging in appropriate situations (Chapters 9, 11).

Figure 1.3 CT scan abdomen shows bilateral adrenal metastasis in small cell lung cancer.

Staging

The purpose of staging is to assess the extent of disease, choose the appropriate treatment and to assess likely outcome of the disease. Staging is also important in the comparison of results between treatment centres. The TNM system has been developed for many cancers. TNM staging denotes tumour, node and metastatic status. T staging is generally based on the size of the tumour (usually according to defined size criteria, e.g. in breast cancer) or depth of invasion in hollow organs (e.g. oesophageal cancer, bladder cancer) or local spread to neighbouring organs or subsites (e.g. supraglottic cancer) (Figure 1.4). N staging is based on pattern of spread along the lymphatic chain, or number of nodes involved or size of nodes involved. It may be clinical or pathological. M1 denotes distant metastasis. Composite staging involves grouping various T, N and M combinations into 4 stages and each site has different stage grouping (e.g. see p. 80). Other descriptors of TNM staging are shown in Box 1.2. Other cancers are staged by slightly different systems such as FIGO for many gynaecological cancers (Chapters 13, p. 197).

Figure 1.4 Staging of cancer.