Malignant pleural effusions: Differentiating pelvic malignancies.

Sir,

We would like to compliment Agrawal et al.[1] on their informative study on malignant pleural effusions in the tertiary care set up. In this regard we would like to emphasize some pertinent aspects.

Cancer of the female genital tract in the aforementioned study accounted for 9.74% of all cases of carcinomatous pleural effusions. The importance can be gauged from the fact that they amounted to 33.7% of all the malignant pleural effusions seen in the female sex (30 of the 89 female patients). Malignant pleural effusions associated with carcinoma ovary constitute a significant subset of these patients. In many studies including Agrawal et al. (as well as several studies[23] quoted by the authors), the significance of this subgroup has been overlooked and the incidence of such cases has not been quoted. Though the general outlook for patients with malignant pleural effusions has been seen to be dismal and the mean survival has been seen to be 3 to 12 months as mentioned in the study. The median survival for patients with this specific subgroup of patients has been seen to be much better i.e 2 years[4] after taxane, platin based chemotherapy. The identification of such patients is readily aided by serum (as well as pleural fluid) Ca 125 levels though specificity remains on the lower side. Thus such patients with better outlook need to be separately identified in such studies.

Also, in the reference study a definitive diagnosis was eluded in 40% of the pleural fluid cytology specimens. Another important subgroup of patients with malignant pleural effusions remains the category of unknown primary malignancies which accounted for 12% of the total patient load. Perhaps immunocytology can be of help in such patients. The application of this technique can be helpful in characterising such patients and the benefit of targeted treatment can be passed on to the ailing patients. Immunohistochemical markers can aid in both differentiating malignant effusions from reactive effusions in cancers as well as differentiating various cancers. Various molecular markers like calretenin, CEA, Ca19-9, Ca 125, CK 5/7, TTf1, Ber-EP4, PSA etc have been found to be helpful though these remain to be standardized.[5] It has been seen to be a simple economical method, which markedly boosts the diagnostic yield of tumorous effusions with cytology. Though in the emerging developing countries problems remain regarding its availability, the use of such a technique can help in improving the grim outlook seen such patients.