Preoperative adjuvant radiation with chemotherapy for rectal cancer: its impact on stage of disease and the role of endorectal ultrasound.
BACKGROUND
Preoperative adjuvant radiation combined with chemotherapy is a recent development in the management of patients with rectal cancer invading perirectal tissue and regional lymph nodes. This study was performed to assess the impact of preoperative adjuvant therapy in patients judged by endorectal ultrasound to have extramural invasion of rectal cancer and/or regional lymph node involvement on tumor regression in bowel wall and lymph nodes. The predictive value of ultrasound in staging wall penetration and lymph node involvement after preoperative adjuvant therapy was also assessed.


METHODS
Patients (n = 43) were selected by ultrasound to have preoperative irradiation (4,500-5,040 cGy over 5-6 weeks). In 30 patients this was combined with 5-fluorouracil, 370 mg/m(2), for 5 days in the first and last weeks of irradiation. Pretreatment ultrasound was compared with pathologic findings in the resected specimen in all patients. Twenty-one were assessed by ultrasound after adjuvant therapy and findings compared with histology.


RESULTS
Downstaging was seen in 23 (53%) patients with wall invasion and in 23 (72%) of 32 patients with lymph node involvement. Overall, downstaging was achieved in 30 (70%). Positive predictive values of ultrasound after irradiation were 72% and 56% for wall penetration and lymph node status, respectively. Negative predictive values of ultrasound after irradiation were 100% and 82%, respectively.


CONCLUSIONS
In the majority of patients with rectal cancer invading perirectal tissues or lymph nodes, lesions may be downstaged by preoperative adjuvant therapy. Endorectal ultrasound after adjuvant therapy for rectal cancer is of a lesser predictive value chiefly because of overstaging.
Bernini
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Department of Surgery, University of Minnesota Medical School, Minneapolis, USA.
Deen
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Madoff
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Wong
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005472:Fluorouracil / Q000627:therapeutic use*; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011300:Preoperative Care; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D012007:Rectum / Q000000981:diagnostic imaging*; D014463:Ultrasonography
D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil