NEW YORK (Reuters Health) – In select patients with American Joint Committee on Cancer (AJCC) stage II colon cancer, adjuvant chemotherapy after resection improves survival, according to a retrospective review of more than 3,700 patients treated in California.
“Our investigation suggests that adjuvant chemotherapy provides a survival advantage for select patients with stage II disease,” Dr. Joseph Kim, associate professor of surgery, City of Hope Comprehensive Cancer Center in Duarte, California told Reuters Health.
Currently, the American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN) both recommend against the routine use of chemotherapy for patients with stage II colon cancer. Likewise, Dr. Kim said his data “do not support routine use of chemotherapy for all patients with stage II disease.”
Rather, he said “clinicians must use their best judgment in identifying appropriate patients and weighing the risks and benefits. Our data do not provide specific characteristics that physicians should use, but do demonstrate that physicians are currently making those decisions,” he added.
The prognosis of patients with AJCC stage II colon cancer is good, with 5-year survival rates ranging from 72% to 85%, the study team notes in the journal Cancer. Still, about one quarter of patients with stage II disease will develop recurrent disease and most will die as a result.
The role of adjuvant chemotherapy in patients with stage II disease “remains controversial,” the investigators note. Their objective was to evaluate the role of adjuvant chemotherapy in patients with AJCC stage II colon cancer within a large, heterogeneous population.
Using the California Cancer Surveillance Program, they identified 3,716 patients who underwent curative-intent resection for pathologically confirmed AJCC stage II colon cancer (ie., T3 or T4 and N0) between 1991 and 2006. A total of 916 patients underwent surgery plus adjuvant chemotherapy, whereas 2,800 had surgery alone.
Patients who received adjuvant chemotherapy were disproportionately younger and had larger tumors ( > 5 centimeters) and their tumors were located more often in the descending or sigmoid colon. There was no difference in sex or tumor differentiation between the two groups. It is noteworthy, the researchers say, that patients who received adjuvant chemotherapy were more apt to have at least 12 lymph nodes examined.
In comparing the two treatment groups (surgery plus chemotherapy vs surgery alone), the researchers found that receipt of adjuvant chemotherapy was associated with a significant improvement in overall survival time (median survival 12 years vs 9.2 years; P < 0.001).
Five-year survival rates were also significantly better with adjuvant chemotherapy (74% vs 66%; P < 0.001).
In multivariate analysis, adjuvant chemotherapy emerged as an independent predictor of improved survival (hazard ratio, 0.88; P = 0.031).
It’s possible, write the researchers, that the observed survival difference between the two groups could have been more pronounced if contemporary systemic chemotherapy agents had been used.