New Delhi, Feb. 8: Doctors involved in the diagnosis and treatment of cancer say it would not surprise them if cricketer Yuvraj Singhs cancer had indeed initially been interpreted as a benign tumour before it was recognised as malignant.
Several medical oncologists and pathologists, who have no direct information about Yuvrajs case, say misdiagnosis is not uncommon in the domain of oncology, where diagnosis and treatment can be particularly challenging.
A New Delhi-based oncologist, Nitesh Rohatgi, who is familiar with Yuvrajs condition, has said the cricketer is under treatment for a condition called mediastinal seminoma, a rare tumour involving germ cells located between a lung and the heart.
Rohatgi declined to comment on whether there had been an initial diagnosis of a benign tumour, but a statement by Yuvrajs mother in November 2011 had said that Yuvraj was recovering from benign tumour in his lungs, the size of a golf-ball.
Medical studies suggest that benign mediastinal tumours, also called teratomas, are typically round masses that grow slowly, while malignant mediastinal seminomas are larger and grow faster.
A pathologist asked to diagnose a tumour is only as good as the sample available for examination, said Deepak Mishra, a pathologist at the Tata Medical Centre, Calcutta, and secretary of the Indian Association of Pathologists and Microbiologists.
The diagnosis of cancer requires a pathologist to screen cells on a microscope slide, looking for telltale signs of malignancy, he said. The cells are often aspirated from the suspect tissue using a fine needle to sample cells.
Sampling errors can lead to misdiagnosis, Mishra told The Telegraph. If the needle doesnt hit the right spot, it may pull out only normal tissue and a pathologist would then be compelled to label the growth as benign, he said.
The number of cells aspirated from the tissue may also influence diagnosis.
If there are plenty of malignant cells, then diagnosis is easy, said Asaranti Kar, an associate professor of pathology at the Sriram Chandra Bhanj Medical College at Cuttack in Odisha. Malignant cells are supposed to appear quite different from normal cells — they are much larger, giants compared to normal cells, dark coloured, and have special features associated with malignancy, Kar told The Telegraph.
Medical oncologists say they are entirely dependent on pathologists diagnosis.
Were constrained by what the pathologists tell us — and pathologists are constrained by the samples they are able to get, said Prakash Chitalkar, an oncologist at the Asian Institute of Medical Sciences at Faridabad in Haryana.
A research study published three years ago by doctors at the All India Institute of Medical Sciences, New Delhi, suggested that a significant proportion of lung cancer patients are initially wrongly treated for tuberculosis.
The main source of diagnostic error was a delay to investigate suspicious patches seen on lung X-rays via CT scans, and the forgotten art of reading chest X-rays in the age of CT and MRI scans, physician Randeep Guleria and his colleagues said in a research paper in the Asian Pacific Journal of Cancer Prevention.
But benign lesions may also turn malignant in some tissues, oncologists say. Two examples are the transformation of pre-cancerous lesions in the mouth or the cervix in women into cancer. Both oral and cervical cancers are common in India. A research team in the Netherlands had in 1997 documented the transformation of a benign bone tumour into malignant cancer.
Chitalkar and other oncologists said the standard treatment for mediastinal seminomas involves chemotherapy and radiotherapy. The five-year survival rate in this condition is anywhere from 60 to 80 per cent, Chitalkar said.