Primary mucinous carcinomas of the lung: Clinical characteristics and treatment outcomes

Abstract

Introduction: Invasive mucinous adenocarcinoma (IMA) of the lung is a distinct histologic variant of adenocarcinomas comprising about 2%–10% of lung adenocarcinomas. A large proportion of IMAs carry KRAS mutations and only rarely epidermal growth factor receptor (EGFR) mutations or ALK/ROS translocations; thus, most cases are not amenable for targeted therapy at present. This study was conducted to elicit the unique clinicopathological characteristics of IMA. Materials and Methods: Medical records of patients diagnosed with IMA by needle biopsy at Kidwai Cancer Institute, Bangalore, from 2013 to 2018, were retrieved and reviewed. Statistical analysis was performed using SPSS version 23.0 (IBM Corp., Armonk, NY, USA). Results: Four hundred and ninety cases of needle biopsy of the lung were diagonosed at our institute between January 2013 and December 2018. Nine cases (1.8%) were diagnosed as IMA. The median age of presentation was 59 years. Six (66.7%) were current smokers with pack-year > 20. Three (33.3%) of the cases were initially misdiagnosed as pneumonia in view of computed tomography findings. The lung was the most common site of metastasis (77.8%). Serum Carcinoembryonic Antigen (CEA) was elevated in six cases (66.7%). None of the cases had any driver mutations in EGFR gene or ALK and ROS1 translocations. All cases were treated with pemetrexed–carboplatin doublet followed by pemetrexed maintenance till progression. The median progression-free survival (PFS) was 15 months (range: 5–18 months). Docetaxel was given as the second-line chemotherapy in all progressed patients. Best response noted was stable disease, seen in 4 (57.1%) cases. The median PFS for docetaxel was 6 months (range: 3–8 months). The median overall survival was 22 months (range: 9–27 months). Patients with initially raised CEA at progression had a serial rise in serum CEA. Conclusions: IMA is rarely diagnosed on needle biopsies due to insufficient tissue. They mimic pneumonia on imaging, thus delaying diagnosis. EGFR mutations, ALK, and ROS1 translocations are usually negative making them ineligible for tyrosine kinase inhibitors. Response to chemotherapy is modest.

Systemic immune-inflammation index predicts survival in patients with resected lung invasive mucinous adenocarcinoma

“…Because of limited reported cases, there was no significant clinicopathologic prognosticator for pneumonic-type IMA, even the recognized TNM staging. For the relationship between pneumonic-type IMA and bad prognosis, a possible explanation is that the tumor mimic pneumonia on imaging, thus delaying diagnosis and treatment [ 28 , 29 ], but it still doesn't explain those patients still had a shorter survival time who accepted an undelayed operation. Systematic inflammatory response is a common accompaniment to pneumonic-type IMA, may lead to an elevated SII.…”

Mucinous Adenocarcinoma of the Lung: A Great Mimicker of Pneumonia

“…It was formerly known as bronchioloalveolar cell carcinoma [ 3 ]. It accounts for about 5% of lung carcinomas [ 4 ]. The diagnosis can be difficult on small biopsy specimens [ 4 ].…”

“…It accounts for about 5% of lung carcinomas [ 4 ]. The diagnosis can be difficult on small biopsy specimens [ 4 ]. This type of tumor does not have a specific clinical manifestation [ 3 ].…”

Current and future role of double-lung transplantation for bilateral lung cancer

“…Furthermore, two other studies revealed that resectable and stage IV IMAs exhibited better OS than non-IMAs with similar characteristics [ 53 , 54 ]. These inconsistent results may be attributed to prognostic differences among IMA phenotypes or the presence of prognosis-related factors such as spread through air spaces (STAS) or mucin-producing characteristics [ 44 , [55] , [56] , [57] , [58] ]. Additional research on histology-related prognosis or prognosis-related factors could help identify more suitable candidates for lung transplantation and broaden the indications for this procedure.…”