The importance of patient selection for adjunctive postoperative radiation therapy for cancer of the rectum. Patient selection in adjunctive therapy.
BACKGROUND
Clinical stage of disease is an important selection criterion for choice of primary treatment and strategies for adjunctive therapy for most cancers. For adenocarcinoma of the rectum, strategies for adjuvant treatment are based primarily on pathologic stage alone, without consideration of presenting clinical factors. This analysis was undertaken to assess the effect of patient selection on results of adjunctive therapy.


METHODS
Three groups of patients with Astler-Coller Stage B2 and C rectal cancer were compared to assess the effect of patient selection factors on outcome of treatment after adjuvant postoperative radiation. Thirty-two patients in Group 1 received only 5 Gy preoperatively; 54 patients in Group 2 received low-dose (5 Gy) preoperative and high-dose (45 Gy) postoperative radiation; and 53 patients in Group 3 received high-dose (45 Gy) postoperative radiation. All patients have a minimum follow-up of 5 years. Whereas Group 1 and Group 2 patients were similar in distribution by clinical tumor characteristics, Group 3 had more patients with poor clinical features: higher median age, more men, and a higher proportion of tumors in the distal rectum. Group 3 also had a slightly higher percentage of C2 tumors compared with the other two groups.


RESULTS
Treatment was well tolerated with minimal side effects. Patients in Group 1 had no long-term complications. Four percent of patients (2 of 54) in Group 2 and 6% of patients (3 of 53) in Group 3 experienced major small bowel complications. The incidence of local recurrence was 34% (11 of 32) in Group 1, 9% (5 of 54) in Group 2, and 21% (11 of 53) in Group 3. The incidence of distant metastasis was 28% (9 of 32), 22% (12 of 54), and 38% (20 of 53), respectively. Absolute 5-year survival rates were 54%, 72%, and 41% in these three groups, respectively.


CONCLUSIONS
Low-dose preoperative adjunctive radiation alone (Group 1) resulted in a high incidence of local recurrence and poor survival compared with patients treated more appropriately with low-dose preoperative plus adjunctive postoperative irradiation (Group 2). In spite of postoperative radiation, patients with clinically unfavorable rectal cancer (Group 3) did worse than carefully selected patients, although both were nominally Stage B2 and C. Careful patient selection before surgery, histopathologic stage of disease postsurgery, and adequate adjunctive therapy are all important factors in obtaining the best results from adjunctive therapy.
Lingareddy
V
V
Department of Radiation Oncology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107.
Mohiuddin
M
M
Marks
G
G
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary / Q000601:surgery; D000368:Aged; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007415:Intestinal Obstruction / Q000209:etiology; D007421:Intestine, Small / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011182:Postoperative Care; D011300:Preoperative Care; D011878:Radiotherapy / Q000009:adverse effects; D011879:Radiotherapy Dosage; D012004:Rectal Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D016019:Survival Analysis; D015996:Survival Rate