SAN ANTONIO – The literature is somewhat checkered over who can claim bragging rights for improved breast cancer outcomes, but the overall trend has favored surgical oncologists over general surgeons.
What’s driving the improved outcomes isn’t entirely clear, but a new analysis suggests that a key mechanism is that patients treated by surgical oncologists participate in clinical trials at dramatically higher rates, lead author Dr. William Dooley said during a plenary session at a symposium sponsored by the Society of Surgical Oncology.
Dr. William Dooley
Among 1,220 women analyzed for the period of 2001-2008, 56% of 777 patients treated by a surgical oncologist participated in a clinical trial, compared with only 7% of 443 general surgery patients (P value = .000).
Patients in a clinical trial were more likely to stay connected with the system and followed by their treating physician, said Dr. Dooley, the G. Rainey Williams Professor and chair of surgical breast oncology at the University of Oklahoma Breast Institute, Oklahoma City. The average follow-up was 44.6 months for the 468 trial participants vs. 38.5 months for the 752 nonparticipants (P = .000).
Participation in a clinical trial was associated with a significant survival advantage, increasing overall survival from 26% to 31% at 5 years (P = .000).
The benefits of clinical trial involvement cut across the entire health care team, Dr. Dooley said. Radiologists and pathologists receive outside review of and feedback for their work, while outside monitoring tracks the actions of the treatment team, patient progress through the treatment plan, and adherence of all elements of care to the system.
"When we begin to think about clinical trials and groups like ACOSOG [American College of Surgeons Oncology Group], we need to bring forth the spectrum of clinical trials to cover the whole spectrum of breast disease and encourage all surgeons in the country to be involved," he said. "This may be a very dramatic way that we can improve the quality of breast cancer care nationally."
The entire analysis included 2,191 women who received primary breast cancer treatment from 1995 to 2008 at the Breast Institute, with 752 under the care of a surgical oncologist and 1,439 cared for by a general surgeon. The average age of the women was 54 years and 57 years, respectively.
When the researchers compared their outcomes using standardized measures, the case mix included 25% more late-stage disease than the national population. General surgeons performed right at the national average, while additional oncologic training for surgeons provided a 28% improvement in workup and treatment.
But most significantly, the additional training reduced deaths for stage I-III breast cancer from 39% for stage IIIb disease to 57% for stage I disease, Dr. Dooley said.
Another mechanism driving the improved outcomes is that patients treated by a surgical oncologist are far more likely to complete National Comprehensive Cancer Network guideline–compatible therapy in a timely fashion, he said. In all, 77% of stage I-III patients treated by a surgical oncologist completed chemotherapy or hormonal adjuvant therapy, compared with 68.5% of general surgery patients (P less than .02).
Breast conservation rates were significantly higher for surgical oncology patients than for general surgery patients overall (53% vs. 38%, P less than .001), and for stage 0-II disease (66% vs. 54%, P less than .01).
Radiation therapy for breast conservation was completed by 97% of patients treated by a surgical oncologist and 67% of general surgery patients, and by 99% vs. 74% for stage III disease (P less than .001 for each), Dr. Dooley said.
"Good intentions don’t get us very far," he said. "The Commission on Cancer is starting a program to help us monitor initiation of treatment. It’s not the initiation that counts. It’s whether the patients actually finish that treatment completely."
There were no survival differences for women with stage 0 or IV disease, and their data were excluded from the presentation.
During a discussion of the study, an audience member questioned the presence of comorbidities in each group, observing that patients enrolled in clinical trials tend to be healthier. Dr. Dooley responded that details on comorbidities were limited, but that Charlson Index scores were similar in both groups. In addition, he noted that the same beneficial effect of clinical trial participation has been observed even in trials with just tissue banking.
Rates of stage I, IIA, and IIB disease were similar at 20.5%, 30.5%, and 17% in the surgical oncology group and 19.6%, 32%, and 24% in the general surgery group. Chemotherapy, however, was significantly more common among patients treated by a surgical oncologist than among those in the general surgery group (69% vs. 56%).