Current American Joint Commission on Cancer (AJCC) Guidelines Upstage Patients with Synchronous Bilateral pM1a Pulmonary Adenocarcinomas
Ann E Walts, Trista K Leong, Alberto M Marchevsky. Cedars-Sinai Medical Center, Los Angeles, CA
Background: The American Joint Commission on Cancer Staging Manual (AJCC 7th ed) recommends that separate tumor nodules in the contralateral lung without distant metastases be staged pM1a (anatomic stage/prognostic group IV; pStage IV). Criteria to distinguish synchronous primaries from intrapulmonary metastases are not provided by AJCC. We sought to test the clinical validity of this recommendation in patients who underwent resection of synchronous bilateral pulmonary adenocarcinomas (PAC).
Design: Data from our hospital Cancer Registry were used to evaluate 5-year overall survival (OS), 5-year disease free survival (DFS) and median disease free survival (MDFS) in 18 consecutive pM1a patients who underwent resection of synchronous (defined as within 6 mos) bilateral PAC at our hospital. Patients with malignant pleural or pericardial effusions and/or distant metastases were excluded. Results were compared with those in a cohort of 573 consecutive patients (201 pStage I, 64 pStage II, 17 pStage III, 291 pStage IV) who underwent resection of PAC at our hospital during the same time period.
Results: The 18 pM1a patients (10 females, 8 males) ranged from 57 to 83 years in age (median 69.5 yrs) at operation. Their PACs ranged from 0.2 to 5.0 cm in diameter (median 1.3 cm). 17 (94.4%) of these 18 patients had invasive PAC; 1 had minimally invasive PAC. Only 5 (27.8%) patients received chemo- and/or radiation therapy; the remaining 13 received neither. The 5-year OS, 5-year DFS, and MDFS for the 18 pM1a patients were 64.5%, 94.4%, and 646 days, respectively. The 5-year OS, 5-year DFS, and MDFS for the 291 pStage IV patients in the registry cohort were 13.0%, 2.7%, and 0 days, respectively. When compared to results in pStages I-IV of the registry cohort, results in the pM1a study group best approximated those in the pStage I group (5-year OS, 5-year DFS, and MDFS were 69.0%, 27.5%, and 488 days, respectively).
Conclusions: In our patient population, synchronous bilateral pM1a PAC should not be staged as pStage IV in the absence of malignant effusion. Survival statistics for these pM1a patients were far superior to those for pStage IV and appear similar to those for patients with pStage I PAC. Our findings suggest that these pM1a lesions represent synchronous primary lung cancers. There is a need for future AJCC guidelines to include criteria that enable reliable distinction between multiple synchronous primary PACs and intrapulmonary metastases.
Monday, March 4, 2013 1:00 PM
Poster Session II # 294, Monday Afternoon