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Journal of Cancer Research and Therapeutics, Vol. 7, No. 4, October-December, 2011, pp. 391-392 Editorial Resurecting brachytherapy from brink of oblivion Anusheel Munshi Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, India Code Number: cr11108 DOI: 10.4103/0973-1482.9199 From too much zeal for the new and contempt for what is old Good Lord, deliver us. - Sir Robert Hutchison Brachytherapy is a unique form of radiotherapy involving science, skill, and judgment. This technique is useful in approximately 5-10% of all cancer patients. [1] Sometimes it needs to be reiterated that brachytherapy was the first radiotherapy modality to be used for treatment on cancer patients, much before the first teletherapy machine was invented. [2] In early 20th century this fine art evolved under the astute guardianship of stalwarts like Madam Curie, Paterson, Parker, Fletcher, Deutrix, to name a few. With painstaking effort, Paterson and Parker established norms for uniform dose rate at a point, designated point A in carcinoma cervix patients. [3] This constant dose rate held true for various combinations of tandem and ovoid loading patterns and was thus a remarkable feat indeed in that era. Calculations and rules for other systems followed, including the famous rules of the Paris system. [4] The concept of brachytherapy was appealing. One put the radioactive source close to the patient, often in the tumor itself, took advantage of inverse square law in getting a low dose to the normal structures, and kept the treatment "inside out" (as opposed to outside in treatment for teletherapy). [5] The decades of 30's to 70's in the 20th century could be easily regarded as the golden period of brachytherapy. During this period, radiation oncologist and physicists developed newer treatment techniques and patterns for brachytherapy care. It became the dominant mode of treatment in superficial and accessible tumors. Low-dose rate techniques were established, with the evolution of the iridium wire, cesium needle, various seeds, and pellets. [6] This was also the time when the teletherapy machines had just been conceived. Consequently, teletherapy treatment was simple, often consisting of square or rectangular portals. Naturally, brachytherapy provided the only means for a "conformal treatment or conformal boost." Clinicians and physicist therefore spent considerable time and attention to fine tuning this technique and took justifiable pride in the outcomes of this technique. But a series of events in the past decades have lead to a severe decline in interest in the art of brachytherapy. Its first cousin, teletherapy has made phenomenal strides which have seemingly buoyed radiation oncology to a superfast and supersonic era. Orthovoltage and telecesium machines have become curiosities for present day residents and trainees. Contouring-based treatment, akin to surgical resection of the tumor and lymph nodes with sparing of the normal structures has become the norm in most centers. Intensity-modulated radiotherapy has allowed radiation oncologists to give integrated and highly conformal treatments or avoidance, as the case may be, a capability hitherto confined to brachytherapy treatment. [7] Teletherapy has attempted to make inroads even the brachytherapy stronghold of carcinoma cervix. Advancements such as proton therapy have shown the ability to give near zero dose distal to the desired area. [8] Feasibility studies have been done to see the role of superfine rotational therapy and arc therapy techniques as a substitute for brachytherapy in cervical cancers. [9],[10] Features such as image guidance, gating, and 4D techniques lead to a natural decline in doing brachytherapy procedures because in hand was a noninvasive technique which fulfilled the dosimetric wish list of the radiation oncologist. These were welcome advancements for many oncologists wary over the issue of summation of doses to a given region by teletherapy and brachytherapy. This had always been a vexed issue, with its complexities of matching doses and dose rates by converting them to a "teletherapy equivalent." [11] Ostensibly, the High Dose Rate (HDR) treatment system brought in various welcome changes in the form of exposure protection, shortened treatment time, and patient convenience. It seemed a clean and effective way of delivering Brachytherapy. The advantages and uniqueness of HDR planning systems for brachytherapy include possibilities for the differential loading of applicators in an attempt to produce an ideal dose distribution. [12] Practically however, radiation biologists, physicists, and radiation oncologists could never decide, besides other issues, on a specific model for Low Dose Rate (LDR) to HDR conversion. These conversion factors varied for various sites and various dose fractionations. Even after application of some models, radiation oncologists were uncertain about the late sequelae from use of this much higher dose rate. [13],[14] To add to the list, further challenges to brachytherapy were posed by poor reimbursement patterns for this treatment. Typically, Brachytherapy in HDR is delivered in dose per fractions varying from 3-9 gray (compared to 1.8 to 2 Gy per fraction for the external radiotherapy) depending on site and surrounding organs at risk. Fewer fractions translated into lesser reimbursements (owing to a commonly followed per fraction reimbursement pattern). This trend of poorer reimbursements was visible in the western nations and the sentiment has been duly echoed in private Indian hospitals as well. [15] Taking the argument further, even academic organizations such as ESTRO, ASTRO, and AROI have kept brachytherapy out of the focus area. As an example, of the 35 courses listed in the ESTRO calendar for 2012, only 3 directly address the topic of brachytherapy. [16] Further, and of note, brachytherapy is a technique involving hand skills. Hands on workshops for young impressionable minds are the need of the hour. Contemporary brachytherapy experts have played their bit in not having disseminated this art to their pupils and perhaps failed to make this field exciting and continuously evolving. As a result, for the present, IMRT, IGRT, 4D treatment, and proton beams are ruling the roost. Among this picture of gloom, some silver linings do flash. Mammosite/Mammasphere/SAVI for breast cancers, Magnetic resonance imaging (MRI)-based cervical/parametrial implants, and gliasite for brain tumors are modern innovations of brachytherapy. [17],[18],[19],[20] Intravascular and intraluminal therapies too have been innovatively used. Where does brachytherapy go from here? Rekindling the flame of brachytherapy may well require a Herculean effort. We need to use this fine art wherever possible, remembering that as of now, this technique still remains unmatched in its sharp fall off and precision in its treatment delivery. For brachytherapy and its future, the call could be close. Is Sir Robert Hutchison (and Madam Curie) hearing? References
Copyright 2011 - Journal of Cancer Research and Therapeutics |
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