Introduction

Core needle biopsies (CNB), with or without vacuum assistance, have become the gold standard for the diagnosis of palpable breast lumps.[1] The advantages of core needle biopsy are well documented in many meta-analyses and retrospective studies over fine needle aspiration or surgical excision biopsies. In the era of individualistic therapy and with the greater use of neoadjuvant, and immunotherapy based on Immunohistochemistry, pathologists are more contributary in deciding treatment protocol for the surgeons.[2]

For precision of core needle biopsy diagnosis, CNB is safe and economical especially among rural populations, more over CNB can also be used for preoperative axillary staging and tumour markers.[3] CNB has no absolute contraindication, but there should be caution while in patients who have coagulation disorders or are on anticoagulants with suitable precaution, with seeding of malignant cells not being of any concern.[4]

CNB may be used preferably in palpable masses, along with mammographic units, under ultrasound guidance, or Magnetic Resonance Imaging (MRI). The cutting core biopsy (CCB) is a 12–14-gauge spring-loaded device that fires a cutting needle into the breast tissue. Multiple insertions are needed for sampling the target. Vacuum Assisted Biopsy (VAB) is increasingly becoming useful in both diagnostic and therapeutic approaches, though it is mainly used for microcalcification sampling, whereas CCB is preferred for mass-forming lesions.[5] For patients with malignant lesions, both CCB and VAB are equally helpful and allow for complete pre-operative diagnosis, improving multidisciplinary patient decision-making.

CNB has certain limitations, such as some technical difficulties in deeply located lesions, small or central lesions in large dense breasts and resistance to trucut needles, with complications including pain and hematoma formation.[6] Technical expertise and experience of the surgeons and pathologists help in fruitful outcomes.[7] The present study was undertaken to assess the impact of CNB as a diagnostic tool in patients with palpable breast lumps.

Methods:

In this cross-sectional prospective study, female patients with palpable breast lumps who presented to the surgery outpatient of our tertiary teaching hospital between October 2022 to September 2023 were included. This study had the approval of our Institutional Ethics Committee. Tru-Cut biopsy needle (12-14 gauge) was used for all CNBs and performed under local anaesthesia in the outpatient department. No.11 blade was used to make the skin incision to permit easy entry of the trucut needle into the breast lump. The lesion was held steady with the nondominant hand while the biopsy needle was advanced into the breast lesion to obtain the sample. A minimum of two samples that filled the needle gap were considered adequate. Based on the histopathology report treatment was planned, if malignancy, staging investigations were done and taken up for surgery with no further confirmation tests dependent on the staging. The tissue diagnosis made from CNB was compared with the final histopathology report of the operated specimen. Those with benign pathology reports were followed by mammography every year, and then annually for up to 2 years for patients above 40 years. Breast self-examination procedure was taught to all the study population, and instructed to do breast self-examination and report the notice any changes.

Results:

A total of 102 female patients with palpable breast mass underwent CNB using TRUCT Needle size 14. The procedure had to be repeated in 7 (8.1%) (95% CI, 3-13%) patients because the samples obtained at the first attempt were found inadequate. Tumour homogeneity was equal in breast lesions in terms of size. Of the cases, 44 (41.1%) tumours were in the upper outer quadrant of the breasts and 6 (8%) tumours were central. In 76 patients (69.6%) (95% CI, 61.1- 78.2%) CNB indicated malignancy, including 49 (43.8%) (95% CI, 34.6- 52.9%) cases of invasive ductal and 5(19.5%) (95% CI, 6.4-82.9%) cases of invasive lobular carcinoma. (Table 1) In this group, 49 patients (67%) had other findings at physical examination and imaging that were also in favour of malignancy.

Malignant histopathologic diagnoses made at the CNB sample were in concordance with those of surgery specimens in all (100%) of these cases. Thirty-two (30.4%) (95% CI, 21.8-38.9%) CNB reports indicated benign lesions. On yearly follow-up for 3 years, 25 of those patients (73.5%) (95% CI, 58.7-88.4%) had open biopsy and led to the detection of one malignant case (2.9%) (95% CI, 0-8.6%). This patient underwent an open biopsy within less than one year after her benign CNB report, because of enlargement of breast mass and mammography findings suggestive of malignancy. The remaining 9 patients (26.5%) developed no suspicious changes. Since CNB missed one malignant case (out of 76), according to the gold standard defined as positive surgical biopsy or positive follow-up, its sensitivity for the diagnosis of malignancy was calculated as 98.7% (95% CI, 94.1-100%) and the specificity of the CNB procedure was 100%. CNB sensitivity was calculated as 100% for benign lesions and its specificity was 98.7% (95% CI, 94.1-100%). Overall CNB accuracy was 99.1% (95% CI, 97.4-100%) (Table 2)

Discussion:

Palpable breast lumps are commonly seen in the female rural population as many women do not come for the screening in the early stages due to social reasons, lack of awareness, and ignorance about complications[7]. However, of late, screening cases started coming up due to initiatives taken by government and non-government organizations to create awareness, but this too has a long way to go, especially among rural populations.

Though cytological diagnosis may be obtained using fine-needle aspiration (FNA), CNB provides more clarity regarding the infiltration of the basement membrane, and immunohistochemistry felicitates in decision-making[8]. Over the past decade, CNB has become the golden standard in the diagnosis and management of palpable breast lumps. Since CNB provides an accurate preoperative diagnosis of palpable breast lumps with histopathology, and hormone receptor status, it should be the first line of diagnosis[9], particularly for rural women who cannot make multiple visits to the hospital for obvious reasons like loss of work days, or family issues.

CNB is an economical, reliable outpatient procedure, which gives a diagnosis with a competent skilled team of surgeons, and experienced pathologists. CNB is considered a highly accurate method compared to FNAC in diagnosing breast carcinoma with a sensitivity of approximately 95% to 97 %.[10] Though FNAC, costs low, is safe, easy to perform, and less invasive, it may need further evaluation of HPE in deciding the mode of treatment as mere confirmation alone is not sufficient. For CNB, as with FNA biopsy, the false positive rate is very low. False negative rates are significantly lower than for FNA biopsy, but higher with needles smaller than 14 gauge, with freehand rather than image-guided biopsy, and with less experienced operators.[11]

Most authors do not recommend definitive treatment based on FNAC. The presence of malignant cells in cytology cannot differentiate between in situ and infiltrating breast cancer. However, CNB provides all the necessary information for decision-making in the management of breast cancer with an accuracy quite higher than that of FNAC.[12] The meta-analysis by Ivan et al documented an excellent correlation between the histopathology report of CNB and excisional biopsy in the diagnosis of benign and malignant breast lesions, compared to cytological study.[13]

A false negative rate is very crucial to the accuracy of tissue sampling. We reported a FNR of 1.2% which is comparable to previous reports, ranging from 1.1 to 39%. In this study, the concordance rate between CNB pathology and final pathology for malignant lesions was 100 % (false positive rates: 0%).

CNB has some issues like inadequate sampling, inconclusive reporting, post-procedure haematoma, and pain[12]. The inadequacy rate for CNB in our patients was 7%, comparable to recent other similar research, and meta-analyses done by Verkooijen HM, Peeters PH et al. (2-10 %).[14]

Compared to studies of image-guided CNB, we report higher sensitivity for CNB in breast cancer diagnosis (98.7% versus 96.3%). This may be largely attributed to our inclusion criteria (only palpable masses) and may be in part explained by the experience of the surgeon and pathologist on CNB. Recent studies have documented that, core needle biopsies, with or without vacuum assistance, have become the gold standard for diagnosis of palpable and non-palpable breast lumps[15].

At present with the greater use of neoadjuvant treatment, the pathology reports and mammograms are critical in guiding the decision-making of breast lumps.[16] However, diagnostic inaccuracies may happen due to the small size of the sample and accurate radiological and histopathological correlation is needed for optimal patient management. Core needle biopsy is preferred to an excision biopsy, especially in patients over 40 years of age as this will sufficiently reduce waiting time and cost among the rural populations, with early confirmatory diagnosis.[17] This can also be considered the procedure of choice for accurate pre-operative diagnosis of palpable breast lumps.

Conclusion:

Core needle biopsies can potentially spare patients with benign breast lumps from unnecessary surgery, although we must be cautious about false-negative results. For patients with malignant lumps, preoperative diagnosis by core needle biopsy allows definitive diagnosis, and treatment plans, for better surgical outcomes. In the present study, the accuracy of CNB for malignancy was 99.1% (CI 95%, 97.4- 100%), in addition to high sensitivity, excellent specificity and zero false positive rate. The results of the current investigation, when combined with findings from previous studies, demonstrate that CNB can be reliably used for the preoperative diagnosis of palpable breast lesions as the first diagnostic step with high sensitivity, specificity, and accuracy for both malignant and benign lesions. However, benign lesions, diagnosed this way, must be followed by frequent examinations. Future large-scale studies may substantiate our conclusion.

References:

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