Maximal cytoreductive surgery for advanced ovarian cancer

Early symptoms of ovarian cancer can be similar to those of other pelvic or abdominal conditions and include persistent bloating, pain in the pelvis and lower abdomen, urinary frequency and urinary urgency. Ovarian cancer is usually at stage 3 or 4 when it is diagnosed and the outcome is generally poor. The overall 5‑year survival rate for ovarian cancer is about 43%, and is lower for people with more advanced disease. The stage of the disease at diagnosis is the most important factor affecting outcome and is defined by the International Federation of Gynecology and Obstetrics (FIGO) system:

• Stage 1 (A to C): the tumour is confined to the ovary.

• Stage 2 (A, B): the tumour involves 1 or both ovaries and has extended into the pelvis.

• Stage 3 (A to C): the tumour involves 1 or both ovaries with microscopically confirmed peritoneal metastasis outside the pelvis, or regional lymph node metastasis (if cancer cells are found only in fluid taken from inside the abdomen the cancer is stage 2).

• Stage 4 (A, B): there is distant metastasis beyond the peritoneal cavity (if ovarian cancer is only found on the surface of the liver and not within the liver itself, then the cancer is stage 3).

The FIGO stage does not fully take into account the tumour load and disease extent in advanced disease.

NICE's guideline on the recognition and initial management of ovarian cancer describes the initial management options. The main treatments for advanced ovarian cancer are surgery to remove all macroscopic residual disease (residual disease is cancer left behind at the end of cytoreductive surgery; this type of surgery is also known as debulking) and chemotherapy. Standard surgery usually involves, as a minimum, bilateral salpingo-oophorectomy, total abdominal hysterectomy and omentectomy. Maximal cytoreductive surgery uses additional surgical procedures, including upper abdominal surgery, with the aim of achieving no residual disease. The most important factors affecting outcomes after surgery are responsiveness to platinum-based chemotherapy and the amount of residual disease.

Conventional imaging techniques cannot accurately predict the distribution or volume of disease before surgery. Therefore, the only definitive assessment of the distribution or volume of disease found in the abdomen and pelvis is done at the time of surgery. Currently, no objective tools exist to select people for surgery and a decision for surgery will depend on many factors, including fitness, patient choice, availability of surgeons with appropriate expertise and resource levels.

The aim of maximal cytoreductive surgery for advanced ovarian cancer is to safely remove all identifiable disease, to improve survival, compared with surgery that leaves residual disease. It is a development and extension of standard surgery for ovarian cancer.

The precise differences between standard, radical and maximal cytoreduction procedures are not well defined. Surgical complexity scores, such as the Aletti system, have been developed to try to quantify the complexity of surgery. Each procedure that is done during the surgery is allocated a score:

• total hysterectomy and bilateral salpingo-oophorectomy: 1

• omentectomy: 1

• pelvic lymphadenectomy: 1

• para-aortic lymphadenectomy: 1

• pelvic peritoneum stripping: 1

• abdominal peritoneum stripping: 1

• rectosigmoidectomy anastomosis: 3

• large bowel resection: 2

• diaphragm stripping or resection: 2

• splenectomy: 2

• liver resection: 2

• small bowel resection: 1.
  
  The total score can then be used to categorise the surgery into low complexity (1 to 3), intermediate complexity (4 to 7) or high complexity (8 and above).