Use of surgical procedures and adjuvant therapy in rectal cancer treatment: a population-based study.

OBJECTIVE: To assess the use of surgical procedures by tumor location and compliance with adjuvant therapy recommendations by tumor stage. The study was conducted in a population-based setting to identify target patient groups for improved care. SUMMARY BACKGROUND DATA: Rectal cancer therapy potentially involves similar patients receiving different treatments. Low anterior resection (LAR), sparing the anal sphincter, and abdominoperineal resection (APR), ablating the anal sphincter, offer equivalent local recurrence and survival rates but may differ in quality of life measurements. The 1990 NIH Consensus Conference recommended that patients with stage II and III rectal cancer receive radiation and chemotherapy in conjunction with surgical resection, but this is not uniformly applied. To interpret the use of these therapies, information on tumor location in the rectum, which is rarely known in population-based studies, is necessary. Patient, hospital, or surgeon characteristics may influence which procedure is performed and whether adjuvant therapy is given.
METHODS: Information about primary, invasive rectal adenocarcinomas diagnosed between 1994 to 1996 in 13 California counties was obtained from the regional cancer registry. Tumor location, determined from abstracted medical text, was divided into the upper, middle, and lower rectum. Hospitals were characterized by teaching status, number of beds, and cancer center designation. Surgeons were categorized as general or colorectal surgeons. Factors associated with a higher use of LAR versus APR in patients with middle and lower rectum tumors and factors associated with a higher use of NIH-recommended therapy in patients with stage II and III disease were separately analyzed.
RESULTS: Among 637 eligible patients, APR was used in 22% of those with middle rectum tumors and 55% of those with lower rectum tumors. Factors significantly associated with a higher use of LAR included female gender, middle rectum location, and treatment in a major teaching hospital versus a nonteaching hospital. Recommended therapy was received by 44% of patients with stage II disease and 60% of those with stage III disease. Factors significantly associated with higher compliance with NIH recommendations included age younger than 60 versus older than 75, age 60 to 75 years versus older than 75, tumor location in the middle or lower rectum versus the upper rectum, stage III disease, and treatment at a teaching hospital versus a nonteaching hospital.
CONCLUSIONS: Patients with similar rectal cancers receive different treatments independent of tumor stage or location. This may result in more APRs performed for middle and lower rectum tumors than necessary and less adequate treatment for stage II and III tumors than recommended.