ASSESSMENT OF TUMOUR VASCULARITY BY TRANSVAGINAL COLOUR DOPPLER ULTRASOUND: A NOVEL PROGNOSTIC FACTOR OF CANCER CERVIX

Background: Ransvaginal Color Doppler Ultrasound is proposed as a novel prognostic tool in women with cervical cancer. We evaluated the assessment of tumour vascularity as a prognostic factor and its correlation with other well-known prognostic factors such as tumour size, parametrial invasion and lymph node status determined by MRI. Method: Transvaginal Colour Doppler Ultrasound (TVCDUS) was used to assess vascularity of tumour among 56 patients with histologically proven cervical carcinoma. A visual analyzing system of 1 to 5 was used to grade vascularity. Correlation between the visual grading of vascularity and size of lesion, lymphadenopathy and stromal invasion were studied. Result: All patients who had a tumour volume of >0.1cm3 had abundant vascularisation (a vascularity of 4 or more on visual grading). Thirteen out of 15 patients who had lymphadenopathy had a visual grading of vascularity of 4 or more. Out of 45 patients who showed parametrial invasion 20 had a visual grading of vascularity of ≥ 4. Conclusion: The vascularity of tumour as assessed by TVCDUS correlated very well with well established prognostic factors of cancer cervix such as lymphadenopathy, parametrial invasion and size of tumour mass lesion. Transvaginal colour Doppler ultrasound is a useful non-invasive method to assess tumour vascularity, which has some value in predicting prognosis.


BACKGROUND
Cervical cancer is the second most common cancer diagnosed among women after breast cancer. Almost 70% of the global burden falls in areas with lower levels of development and more than one fifth of all new cases are diagnosed in India 1 . As per estimates of 2012, around 122,844 new cases of cervical cancer are diagnosed every year in India 2 .
Timely and cost effective assessment of such patients is essential for proper treatment. The factors, which are important to determine the extent of cervical carcinoma, include the size of tumour, its extension, histopathology, invasion of vascular space and the lymph node status. Of these, the growth of new blood vessels or angiogenesis has been known to be a very important factor in the growth and spread of any cancer 3 . Previous studies have shown this to be a very good prognostic factor in a variety of cancers including cutaneous melanoma 4 , breast cancer 5,6 , and cervical carcinoma 6 . But majority of these have been done retrospectively on tissue specimens obtained after surgery.
It was hypothesised that a noninvasive method like transvaginal colour Doppler which can be used to assess tumour vascularity, may help to determine the growth and invasive potential of a tumour. This study was conducted to evaluate the role of transvaginal colour Doppler ultrasound in assessing vascularity of the tumour as a prognostic factor and to study its correlation with the other well-known prognostic factors such as tumour size, parametrial invasion and lymph node status determined by magnetic resonance imaging (MRI).

MATERIALS AND METHODS
This cross-sectional study was carried out at the Gynae-oncology unit, Department of Obstetrics & Gynaecology, in SMS medical college and hospital, Jaipur, Rajasthan, from January 2009 to January 2010. A total of 56 patients with histologically proven locally advanced carcinoma of cervix were included in the study. Staging of cervical carcinoma was carried out on the basis of FIGO Staging System 2009 by examining the spread of lesion by pelvic examination and MRI. Initially a general grey scale transabdominal ultrasound scan assessment was undertaken with a full urinary bladder. The uterus, bilateral adnexa, cervical region and adjacent bladder wall were visualised. With the patient placed in lithotomy position, the transvaginal ultrasound probe was introduced and cervical region was brought in focus and examined for the size of the mass, echotexture, and contour of lesion. Presence or absence of free fluid, lymphadenopathy, and stromal invasion were also noted. An average of 5 recordings were taken from within the cervix. In addition, the flow velocity waveforms of blood vessels in and around the tumour were recorded. All measurements were taken with an angle of insonation <60• and the sonograms were evaluated by a single observer in order to eliminate inter-observer variation.
All the data was entered in an Excel database and analysed using XL Stat and Stat Cal Software. The analysis included the assessment of correlation between the visual grading of vascularity and size of mass lesion, lymphadenopathy and stromal invasion. Informed consent was obtained from all subjects prior to inclusion in the study. Patients were free to make a decision whether to participate in the study and study participation did not alter the usual clinical management. The study was approved by the institutional ethics committee.

RESULTS
The age and FIGO staging of patients included in the present study has been shown in table 1. The majority of cases were over the age of 50 years. There were 31 patients with stage II disease, of which 11 were with stage IIa and 20 with stage IIb disease. 25 patients were with stage III disease, where IIIa and IIIb each constituting 4 and 21 patients respectively.
In this study population, 27 patients had a tumour volume of <0.04 cm 3 . Out of these 15 had a visual grading of vascularity less than 3. Only 7 (25.93%) out of these had a visual grading of 4 or more. Interestingly all patients who had a tumour volume of >0.1cm 3 had abundant vascularisation giving a visual grading of 4 or more (

DISCUSSION
Neovascularisation or development of new blood vessels is a well known factor in the growth and progression of cancers. It is associated with tumour growth, resistance to chemotherapy and the development of invasive and metastatic ability 7 . Reliable non-invasive procedures such as Colour Doppler ultrasound, which enables us to assess the tumour vascularity, would thus be very valuable in the prognostic characterization of patients since the extent of vascularity measured by Doppler correlates well with other markers of tumour growth and metastasis.
Previous studies indicate that the induction of angiogenesis can occur in two ways.
It is either through mutations which activate oncogenes or through mutations inhibiting the functions of tumour suppressor genes 8,9 . It is known that in larger tumours, the blood supply is compromised as the tumour increases in size. Cellular hypoxia is one of the major factors initiating the mechanism of angiogenesis. Low oxygen concentration induces the synthesis of angiogenic factors, including HIF (hypoxia-inducible factor), within the cell 10 . It is also associated with an increase in the activity of the gene encoding vascular endothelial growth factor (VEGF), which is considered the strongest and a key promoter of angiogenesis 11 . This probably may There have also been studies that showed tumour vascularity to be much more significant than lymph node status in determining the survival of patients with cancer cervix 18 . Interestingly, it was found that patients with positive lymph nodes and low tumour vascularity had a better prognosis than patients with negative lymph nodes and high tumour vascularity. Therefore, tumour vascularity seems a significant determinant of outcome similar to the lymph node status or even more. .There have also been numerous studies on whether this tumour vascularity can be used to assess the response of patients to chemotherapy or radiotherapy. Pirhoen et al 19 showed that a decrease in tumour vascularisation during radio therapy

Original PaPers
www.slcog.lk/sljog was associated with a better treatment outcome, whereas persistence of high vascularity was associated with a poor response, thus concluding that colour doppler ultrasound might be useful in early assessment of therapeutic response during radiotherapy.
Our study however had certain limitations. Firstly, the visual grading of vascularity used was observer dependent, making it a subjective measurement. Secondly, the sample size chosen was small to make any definite recommendation. Further studies with larger sample sizes are needed to throw more light on the subject. Whether or not this noninvasive and cost effective means of predicting prognosis can be used in clinical practice, in preference to other prognostic factors needs further study.

CONCLUSION
Transvaginal colour Doppler ultrasound is a useful non-invasive method to assess tumour vascularity. The vascularity of tumour correlates well with the prognostic factors of cancer cervix and this has the potential to be developed in to an independent prognostic factor.