Preoperative staging of rectal carcinoma using transrectal ultrasonography (Trus): experience with 30 Nigerians

Colorectal cancer is the second most common malignancy; accounting for approximately 155,000 new diagnosed cases each year in the United States. It is about the commonest Gastrointestinal Malignancy in Nigeria. For cancers specifically located in the rectum, various therapeutic options are available including local excision, total mesorectal excision, preoperative radiotherapy etc. These treatment modalities vary in morbidity and chance for cure. The choice of surgery as well as possible outcome largely depends on the depth of tumour infiltration of the rectal wall as well as extent of perirectal tissue involvement. The aim of this study was to assess local fixity clinically and also to assess the ability of transrectal ultrasound (TRUS) to fulfil staging requirements in patients with rectal cancer. The results of these findings were compared with findings at operation and subsequent findings at pathological examination. This is with the aim of evaluating the usefulness of transrectal ultrasound in selecting patients for surgical intervention especially with respect to resectability.

Thirty consecutive patients with histologically confirmed rectal carcinoma at UITH, Ilorin from January 1998 to December 2002 who underwent preoperative TRUS were prospectively studied. After clinical examination including digital rectal examination they all had TRUS, proctoscopy and sigmoidoscopy. Result of findings on clinical examination, TRUS, findings at surgery and histological findings were compared and analysed using SPSS 10.0.

There were 30 patients reviewed. Twenty per cent of patients who were thought to have fixation of the tumour on clinical examination were not confirmed on TRUS and at surgery. All the patients that TRUS diagnosed as fixed and therefore not resectable were confirmed at surgery and histopathology. Digital Rectal Examination (DRE) identified four patients with peri-rectal lymph nodes but TRUS picked six; though only five were histologically positive.

TRUS is a useful preoperative imaging technique especially where CT and MRI are not readily available. This can assist the surgeon in preoperative decision taking as to the resectability of the tumour and possible prognosis.