The national practice for patients receiving radiation therapy (RT) for carcinoma of the rectum (RC): Comparative analysis of treatment from the 1992–1994 and 1988–1989 patterns of care studies by academic (AC) vs. non-academic (NAC) centers

Abstract

Listen

Translate article

This retrospective analysis was performed on the PCS 1988–89s1992–94 RC datasets to determine if significant differences exist in the treatment approaches among patients (pts) managed at AC vs. NAC centers. Two PCS national RC surveys were conducted using a 2-stage stratified sampling technique. Information was collected on 406 pts (weighted sample size=11,846)s515 pts (21,676) with RC who received adjuvant pelvic RT at 69 and 57 facilities within the ’88–89s’92–94 survey periods, respectively. 12% of pts were treated at AC in both surveys. AC were defined as an NCI-comprehensive cancer center (CCC) or had 2 or more radiation oncology residents in the ’88–89 PCS, and as a CCC or primary teaching hospital of a medical school in ’92–94. Pts were staged according to 1988 AJCC TNM criteria. Eligibility criteriasstatistical methodology per SUDAAN software, to accurately reflect PCS sampling technique, has been previously described. For comparisons within groups (i.e. AC ’88–89 vs. AC ’92–94) or between groups (i.e. AC vs. NAC), tests for associations were performed using Pearson chi-square statistics. In treatment comparisons between ACsNAC for all pts from both surveys, AC were significantly more likely to use preop chemoradiation (CRT) [22% vs. 7%, p < 0.0001], while NAC displayed a preference for postop CRT (52% vs. 41%, p = 0.0003). AC were significantly more likely to use chemotherapy (CT) [71% vs. 63%, p = 0.002], concurrent CRT with 5-FU (93% vs. 78%, p < 0.0001),sinfusional 5-FU (54% vs. 36%, p = 0.0001). There was a significant increase in the use of bowel-sparing RT techniques at AC (prone position, belly board, 3-field plans, > 6 MV energy, small bowel contrast; all p values < 0.01). Surgical procedure types were similar amongst both groups. Comparisons between survey periods (’88–89 vs. ’92–94) demonstrated a significant decline in the use of RT without CT, most notably at AC (preop RT 13% vs. 2%, p < 0.0001; postop RT 45% vs. 8%, p < 0.0001) in ’88–89 vs. ’92–94 respectively. The use of preop CRT significantly increased (4% ’88–89 vs. 32% ’92–94, p < 0.0001) in AC, with an increase in the use of postop CRT at NAC (41% ’88–89 vs. 58% ’92–94, p < 0.0001). A dramatic change in the role of CT occurred, with a marked increase in the use of any CT (39% ’88–89 vs. 89% ’92–94, p < 0.0001) in AC, and a significant increase in the use of concurrent CRT with 5-FU (54% vs. 96%, p < 0.0001) at NAC. Surgical procedures also changed, as local excision rates were significantly increased at AC over the survey periods (4% ’88–89 vs. 19% ’92–94, p = 0.0009). Additionally, a significant increase in the use of bowel-sparing RT techniques was demonstrated between survey periods for both AC and NAC (prone position, 3-field plans, daily treatment of all fields, belly board; all p values < 0.01). Interestingly, the proportion of pts receiving a total dose (TD) < 54 Gy increased in AC (71% vs. 81%, p = 0.005), while the TD > 54 Gy increased (20% vs. 31%, p < 0.0001) at NAC. Treatment center comparisons from these two PCS RC datasets suggest: 1) only AC have significantly endorsed CT and preoperative CRT-based strategies over the survey periods. This increase in use of CRT strategies may have limited the ability for North American cooperative groups (NSABP R-03, RTOG-9401/INT-0147) to successfully define the optimal CRTssurgery sequence for T3/4 and/or N+ RC; 2) Sphincter-sparing local excision procedures were significantly increased at only AC; 3) AC > NAC have significantly increased the use of bowel-sparing RT planning and delivery techniques; however, 4) delivery of > 54 Gy RT was more common at NAC. [Supported by NCI Grant CA 65435]