MINI LAPAROTOMY FOR ASSESSMENT OF TUMOUR RESECTABILITY IN OVARIAN CANCER
Dr S Sircar, Mr FA Sefre, Glasgow Royal Infirmary
Introduction: Ovarian Cancer is a ‘silent killer’, with over 600 new cases diagnosed every year in Scotland, with a 5 year survival rate of 30%. Computed Tomography (CT) scan is used to determine preoperative disease extent and prediction of tumor respectability, which determines the candidacy for effective cytoreductive surgery. First line treatment is surgery followed by chemotherapy. Neo adjuvant chemotherapy is considered if optimal de-bulking is not possible at first instance. However, cases deemed resectable based on CT scan can be deemed unresectable during laparotomy. This leads to delay in future chemotherapy. The aim of this pilot study was to compare mini laparotomy to CT scan to assess resectability.
Methodology: This pilot study was carried out in a Gynaecological Oncology centre in Glasgow. Data was collected prospectively from 50 cases of ovarian cancer all deemed suitable for optimal cytoreductive surgery by CT scan. Patient’s weight, height, abdominal girth and tumour markers were measured. Prior to laparotomy, a mini laparotomy was performed through a midline incision. The size of incision would be enough to introduce surgeon’s hand. A thorough systemic palpation of abdomen and pelvis was carried out. Size of initial incision was measured. Time needed to enter the abdomen and to complete the exploration was also noted. The decision about resectibility was classified as ‘resectable’, ‘unresectable’ or ‘unsure’. Formal laparotomy was then carried out and at the end the surgeon would comment on the cytoreduction as either being ‘optimal’ or ‘suboptimal’.
Result : Results from 45 cases were analysed as 5 cases did not have enough information. The average BMI and abdominal girth was 27.24 kg/m2 (25-42kg/m2) and 94.33 cm (42-125cm) respectively. The average size of incision was 8.78cm (5-12cm). The time to enter the peritoneal cavity and to finish exploration was averaged to 5.15 minutes (1-15) and 7.65 minutes (2-30minutes) respectively. Out of 45 cases 27 were deemed resectable by mini laparotomy, out of which 24 had optimal debulking on laparotomy. 10 were commented upon as ‘unsure ‘and only 3 had optimal debulking carried out. 8 were classed as ‘unresectable’ and none of them had optimal debulking surgery upon laparotomy. The only noted complication was bleeding in 2 cases (4%)
Analysis: The specificity of mini laparotomy to predict optimal debulking was around 67%. The sensitivity was 100% with PPV of 85.7% and NPV of 100%. When ‘unsure’, 70% was sub-optimally debulked at the end of surgery. Factors like tumour marker level, BMI, abdominal girth had no significant effect in predicting the resectibility.
Discussion: Optimal debulking remains the gold standard of treatment for ovarian cancer. The modality to stage the disease is mainly by CT scan. Current high-resolution multi-detector CT scanners are known to have around 63% sensitivity, 100% specificity. When using multi-planar reconstruction it reaches 100% positive predictive value (PPV) and 52% and negative predictive value (NPV). In this study, mini laparotomy has a PPV of 86% and NPV of 100%. It was concluded that mini laparotomy would be useful in a sub group of patients, where CT san is ambiguous. It can act complimentary to CT scan and would prevent unnecessary laparotomy if mini laparotomy is suggestive of unresectable tumour. By avoiding laparotomy, patients will have quicker recovery time, quicker initiation of chemotherapy, reducing patient morbidity and hospital stay.The most important limitation of CT scan is its inability to detect small implants, especially on bowel surface, mesenteric or peritoneum in the absence of ascites, which can be reliably detected by mini laparotomy, therefore complimenting each other.
The limitation of the study lies is small numbers, perhaps leading to Type 1 error in statistical analysis. A bigger prospective study could be undertaken to overcome this.