MESOTHELIOMA-GENERAL INFORMATION

General Information About Malignant Mesothelioma Treatment

·         Diagnosis and Prognostic Factors

o    Prognostic Scoring Systems

·         Follow-up and Survivorship

·         Carcinogenesis

Diagnosis and Prognostic Factors

Prognosis in malignant mesothelioma is difficult to assess consistently because there is great variability in the time before diagnosis and the rate of disease progression. In large retrospective series of pleural mesothelioma patients, important prognostic factors were found to be:[1,2][Level of evidence: 3iiiA]

·         Stage.

·         Age.

·         Performance status.

·         Histology.

Prognostic Scoring Systems

Two prognostic scoring systems have been developed for advanced unresectable mesothelioma and are used to stratify patients enrolling in clinical trials: the Cancer and Leukemia Group B (CALGB) index and the European Organization for the Research and Treatment of Cancer (EORTC) index.

CALGB index

The CALGB index was developed retrospectively using the clinical characteristics of 337 patients treated on clinical trials of chemotherapy for advanced mesothelioma during a 10-year period.[3][Level of evidence: 3iiiA] These characteristics were used collectively to define six prognostic groups with median survivals ranging from 13.9 months (Eastern Cooperative Oncology Group [ECOG] performance status [PS] = 0, age <49 years; or PS = 0, age ≥49 years and hemoglobin ≥14.6g/dL) to 1.4 months (PS = 1 or 2 and white blood cell [WBC] count ≥15.6 × 109/L).

The prognostic value of the CALGB index was evaluated retrospectively in a phase II clinical trial of 105 patients.[4][Level of evidence: 3iii] Median survival in this study for patients in the best CALBG prognostic group was 29.9 months compared with 1.8 months for patients in the worst prognostic group. However, the intermediate groups 2 to 4 overlapped in their survival times.

EORTC index

The EORTC index was also developed retrospectively using the characteristics of 181 patients from five phase II clinical trials of chemotherapy during a 9-year period.[5][Level of evidence: 3iiiA] In a multivariate analysis, the following characteristics were associated with poorer survival:

·         WBC count >8.3 × 109/L.

·         ECOG PS ≥1.

·         Unconfirmed histology on central review.

·         Nonepithelioid histology.

·         Male gender.

Patients were allocated a numerical prognostic score based on each of these variables (+0.55 if WBC >8.3 × 109/L, +0.60 if ECOG PS ≥1, +0.52 if unconfirmed histology, and +0.60 if male gender). Subsequently, patients were classified into two prognostic groups that included low-risk patients with a prognostic score of ≤1.27 (0–2 risk factors) and high-risk patients with a prognostic score of >1.27 (3–5 risk factors). High-risk patients had a relative risk of death of 2.9 compared with low-risk patients, P < .001; the 1-year survival rate was 40% for the low-risk group compared with 12% for the high-risk group.

Follow-up and Survivorship

Multimodality therapy incorporating radical surgery (extrapulmonary pneumonectomy or radical pleurectomy with decortication) with or without chemotherapy, administered with or without radiation, may be considered for patients with limited disease and has been associated with a relatively long survival in observational series.[6][Level of evidence: 3iiiA] For patients treated with aggressive surgical approaches, factors associated with improved long-term survival include the following:[7,8][Level of evidence: 3iiiD]

·         Epithelioid histology.

·         Negative lymph nodes.

·         Negative surgical margins.

For those patients treated with aggressive surgical approaches, nodal status is an important prognostic factor.[7] Median survival has been reported as 16 months for patients with malignant pleural disease and 5 months for patients with extensive disease. In some instances, the tumor grows through the diaphragm making the site of origin difficult to assess. Cautious interpretation of treatment results with this disease is imperative because of the selection differences among series. Effusions, both pleural and peritoneal, represent major symptomatic problems for at least 66% of the patients. (Refer to the PDQ summary on Cardiopulmonary Syndromes for more information.)

Carcinogenesis

A history of asbestos exposure is reported in about 70% to 80% of all cases of mesothelioma.[1,9,10]

References

1.     Ruffie P, Feld R, Minkin S, et al.: Diffuse malignant mesothelioma of the pleura in Ontario and Quebec: a retrospective study of 332 patients. J Clin Oncol 7 (8): 1157-68, 1989. [PUBMED Abstract]

2.     Tammilehto L, Maasilta P, Kostiainen S, et al.: Diagnosis and prognostic factors in malignant pleural mesothelioma: a retrospective analysis of sixty-five patients. Respiration 59 (3): 129-35, 1992. [PUBMED Abstract]

3.     Herndon JE, Green MR, Chahinian AP, et al.: Factors predictive of survival among 337 patients with mesothelioma treated between 1984 and 1994 by the Cancer and Leukemia Group B. Chest 113 (3): 723-31, 1998. [PUBMED Abstract]

4.     Mikulski SM, Costanzi JJ, Vogelzang NJ, et al.: Phase II trial of a single weekly intravenous dose of ranpirnase in patients with unresectable malignant mesothelioma. J Clin Oncol 20 (1): 274-81, 2002. [PUBMED Abstract]

5.     Curran D, Sahmoud T, Therasse P, et al.: Prognostic factors in patients with pleural mesothelioma: the European Organization for Research and Treatment of Cancer experience. J Clin Oncol 16 (1): 145-52, 1998. [PUBMED Abstract]

6.     Flores RM, Pass HI, Seshan VE, et al.: Extrapleural pneumonectomy versus pleurectomy/decortication in the surgical management of malignant pleural mesothelioma: results in 663 patients. J Thorac Cardiovasc Surg 135 (3): 620-6, 626.e1-3, 2008. [PUBMED Abstract]

7.     Sugarbaker DJ, Strauss GM, Lynch TJ, et al.: Node status has prognostic significance in the multimodality therapy of diffuse, malignant mesothelioma. J Clin Oncol 11 (6): 1172-8, 1993. [PUBMED Abstract]

8.     de Perrot M, Feld R, Cho BC, et al.: Trimodality therapy with induction chemotherapy followed by extrapleural pneumonectomy and adjuvant high-dose hemithoracic radiation for malignant pleural mesothelioma. J Clin Oncol 27 (9): 1413-8, 2009. [PUBMED Abstract]

9.     Chailleux E, Dabouis G, Pioche D, et al.: Prognostic factors in diffuse malignant pleural mesothelioma. A study of 167 patients. Chest 93 (1): 159-62, 1988. [PUBMED Abstract]

10.                       Adams VI, Unni KK, Muhm JR, et al.: Diffuse malignant mesothelioma of pleura. Diagnosis and survival in 92 cases. Cancer 58 (7): 1540-51, 1986. [PUBMED Abstract]