Carcinomatosis

Carcinomatosis is described as a condition in which multiple carcinomas develop simultaneously usually after dissemination from a primary source. It implies more than spread to regional nodes and even more than just metastatic disease. The term is usually taken to mean that there are multiple secondaries in multiple sites.

Strictly, it should be used only for epithelial cancers or carcinoma and not sarcomas or lymphomas, but has been extended to include all types of cancer which have spread. The word is now used to describe conditions with more limited spread as in:

• Leptomeningeal carcinomatosis - involvement of leptomeninges through seeding via the cerebrospinal fluid which occurs either by direct spread or via bloodstream. Any cancer can cause this but adenocarcinomas are most commonly involved.¹
• Lymphangitic carcinomatosis - diffuse infiltration of the lungs with obstruction of the lymphatic channels.²
• Peritoneal carcinomatosis - spread of metastases into the peritoneum usually from ovarian and colorectal cancers.³

Carcinomatosis may be a progression of known disease. It may be the presentation of recurrence or it may be the primary presenting feature. Presentation will depend upon where is affected.

• In the lungs it may present as shortness of breath and haemoptysis.²
• In the liver it often presents as jaundice.⁴
• In the brain there may be headaches, vomiting and neurological features.⁵
• In bones there may be pain or pathological fracture.⁶

When these features present the question is whether this is part of the known disease or something else. For example, is jaundice due to metastatic carcinoma in the liver or gall stones?

When carcinomatosis is the presenting feature it is usual to seek a primary tumour. In 5% of patients, none is found.⁷ Histology may be anaplastic and give no help, although improvements in investigative technology are helping to narrow the differential diagnosis (see below).⁸

The purpose of investigations are to confirm the nature of the disease and to assess its severity extent.

• In cases of unknown primary, FBC may show iron deficiency suggestive of gastro-intestinal malignancy, microscopic haematuria may reveal occult genitourinary malignancy, and occult blood may point to a colorectal cause. In cases where the primary is known, FBC, urea, electrolytes and creatinine and liver function tests may indicate severity.
• Modern imaging techniques such as ultrasound, CT and MRI as well as older investigations such as chest Xray provide very good information and an exploratory laparotomy is rarely required nowadays.
• It may be desirable to obtain tissue for histology. Techniques now employed to assist with differential diagnosis include:⁸
  • Light microscopy
  • Immunohistochemistry - perioxidase-labelled antigen is used to identify specific tumour markers (e.g. PSA)
  • Electron microscopy
  • Chromosome studies - these are occasionally helpful (e.g. DNA amplification of Epstein Barr virus in suspected occult nasopharyngeal carcinoma)

Usually there is no realistic hope of curative therapy although chemotherapy and radiotherapy may have a palliative effect. Surgery may be palliative and "debulking" of tumour before chemotherapy may be helpful.
There are some subgroups of patients who do relatively well with treatment:

• Multi-modality treatment (intrathecal chemotherapy, intravenous chemotherapy, whole brain radiotherapy and radiotherapy to the spinal leptomeninges) has been seen to improve survival rates in patients with leptomeningeal metastases secondary to breast cancer.⁹
• Lymphatic carcinomatosis can sometimes be stabilised or at least the progression reduced by chemotherapy.¹⁰
• Peritoneal carcinomatosis can occasionally be treated with intraperitoneal and/or intravenous chemotherapy. Treatment can be started post-operative or chemotherapy drugs can even be instilled in the abdominal cavity during surgery. These approaches have resulted in demonstrable improvements in survival rates.³

For patients who are incurable, a frank and honest discussion must take place. This may require more than one session and the skills for breaking bad news are required. Other considerations may be dying at home and dyspnoea in palliative care. Pain control in terminal care and nausea and vomiting in palliative care may also warrant attention.

Palliative care should not be seen as a failure. It is a very demanding and very rewarding aspect of medical practice.¹¹